mdocod
Flashaholic
This is a start to finish picture story with commentary of the building of the PhD-M6 adapter. I should warn, there are over 100 pictures here and this may take some time to load. I've compressed them down really good though so if you are on broadband it shouldn't take any longer to load this thread than it would take to download and MP3.
For those not familiar, this is a 3x17670 adapter for the SureFire M6 built in collaboration with CPF member WQuiles (Will). Will has been working on a regulator and I have been building the adapter to support that regulator and cells. The project has been in the works with the help of several other CPF members for a long time now. We are coming close to releasing units and this is a picture story line that covers the building of the adapters themselves. After these adapters are completed, they will be sent to Will to have the drivers built, installed, programmed and calibrated. You can see that proccess in this thread here!
The PhD project was actually what motivated me to get a Mill. I really wanted to be a part of this project, and while it has been a long time coming, that time has not been a waste at all. It has given me the time to practice on the machine and develop other products on it and get a feel for what can be done. This adapter represents the "latest and greatest" of my abilities with the equipment I have.
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The adapters are made primarily from acetyl plastic round rod stock. Here I am cutting pieces of 1.5" diameter to the appropriot length plus some over-size for the main portions of the body. Each adapter consists of 3 pieces cut from 1.5" rod, and a single small piece cut from 1.25" diameter rod to make the "tailcap" thumb nut.
A 10" 15Amp miter saw with a finishing blade (normally for use on wood) works great in most non-reinforced plastics. I've been using this same blade on this same miter saw since I started Odd Mods over 2 years ago. Still cuts like a champ. As many of you know, I often look for bargains on tools, sometimes it bites me but usually it works out pretty well. The miter saw was purchased on "Black Friday" at Lowes for $60 (marked down from $100).
For the first batch of PhDs, I am just doing 10 units. Best to start with small batches to work out any hitches in production before moving on to larger batches. Next thing on my list of things to get is some decent stack-able plastic bins to put parts like this in. I have been using small boxes like this for a long time. I keep getting more boxes as I order supplies and tools so there is a never ending supply of them it seems.
Before I get started machining parts. I like to figure out all of the cutting tools I am going to need for the project and pre-load as many as possible into the ER25 collet holders. Doing this now before chips and plastic "dust" starts flying means a lot less hassle. I give all the mating surfaces of the collet and collet holder a quick wipe with my hands to remove any debris.
All of the plastic pieces that were cut on the saw are over-sized in all dimensions from what I actually need. The saw does not cut to precision anyways, and it's rarely a perfectly straight cut. The Mill will be used with the 2" 6 flute end mill to square up and size up the parts before they start to take shape. Whacking off the top and bottom of each piece to first square it up, followed by a final cut to size is the proceedure I often use. However, this means a ton of cranking the hand wheel on the X-axis of the mill. I was going to buy the Power Feed for the X3 series of Mills, but after reading about them, I've decided against it. (apparently, they do not disengage the motor from the lead screw when turned off, so precision manual work on the X-axis becomes very difficult). For now, I've custom cut a "driver-bit" of sorts from delrin that fits in the 1/2" chuck of the Ryobi cordless drill. It's essentially a big flat-head/block drive.
It works really well by the way! I run about half throttle on the drill in high gear with the mill turning at about 2kRPM. About 50-60IPM by my calculations.
Using the Ryobi works so well for my purposes that I have decided to build a power feed from a cordless drill and computer power supply. I picked up a Dewalt 12V cordless without any working batteries from craigslist for $10 the other day. This project will have to wait till another day, but I think it will work very well when it's all said and done. I'll probably just use the transmission that is attached to the motor and basically just build up a mount for the guts of the drill to hold it out off the end of the table. The clutch will be set a few notches down from "drill" mode to act as a sort of safety measure (since I probably won't bother with kill switches on stops).
Sorry, I'm getting a little off topic there....
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Here we are removing some plastic off and showing it who's boss.
When tightened, the jaws "straighten up" the part to within about a thou across the surface. I don't need it absolutely perfectly square, but within a thou or 3 from the thickest to thinnest part of the "wafer" is nice.
The thinner parts pictured below can't sit down deep in the jaws. I have a shallow step cut out of these jaws just for this type of part size. Since the diameter also will need to be taken down, these thinner parts will only be squared up for now. I need enough material remaining to be able to flip the part and mill down the diameter from both sides. (there are other ways this could be done but so far I like this one)...
These shots we taken with the flash, so the exposure time is very short, the mill is spinning pretty fast, but it looks like I've managed to catch it "in it's tracks" on these shots.
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Now that we have squared up these parts. It's now time to take down the diameter. The top part will be "turned" down to about 1.435"
Before I tell you this next part. Do as I say, not as I do:
I say the following: For turning down parts on a Mill like this, buy a rotary table with a worm drive or at least some kind of hand-crank wheel.
I do the following: The indexing table is turned by hand. This is quick and easy but requires that you pay attention to what the heck is going on. Keeping fingers clear of the zombie killer (nick name for 2" end mill) is absolutely critical and I would never advise that anyone perform this operation. I happen to trust myself and have been turning down plastic parts like this for over a year without a single close call.
Now the larger pieces...
Flip the part, repeat..
As I had mentioned before. I require the additional thickness be left behind on these thinner pieces to have enough available to turn them down and still have material to clamp on to. So now I come along and take that final cut to size up the part.
After sizing up all of the parts. I have a nice pile of plastic wafers that still look pretty baron.. Time to give them some character!
Carefully put the zombie killer away!
Usually after running the X-axis back and forth that many times, I'll put the center finder in the machine and make sure that my zeroed out center position of the indexing table is still in tune.
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Time to take the first cut.
Insert 17mm center-cutting 2 flute end mill into machine. (plunging operations work best with 2 flute cutters in my experience).
Touch off on surface and "zero" out the drop-down indicator.
Move Y axis into position for the first cut.
Plunge cut to the proper depth (minus a bit)
After plunging the cutter every 120 degrees about the part, the Y axis is moved out a little further and the plunging is repeated in each position. This relieves enough material from what will be the battery slots to perform a final plunge and side-milling operation to clean out the slot.
After those steps are complete, we have a part that is starting to look like something....
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Now I install a 5/16" solid carbide center-cutting 2 flute end mill into the machine.
Then I touch down and zero out down in the pockets I milled previously.
Sorry about the over-exposed shots here...
This end mill is used to both clean out the center "tower" of plastic that was left behind by the large cutting operation of the 17mm cutter. after which point, it is moved into position to make a shallow slot cut that the copper "bridge" used for completing the series electrical path between the batteries can be countersunk into.
The battery contacts in the adapters are made from (primarily) 6-32 brass screws located in the center of each "pocket." Holes are drilled (to be tapped later) to accommodate these screws. After cutting the slow pictured above, I re-find center on the X-axis and then move the Y axis out to the position where these holes need to be drilled.
Since I am working on the end of the adapter that the regulator sits on, one of those holes is actually drilled to accommodate a 4-40 size screw. The regulator needed every bit of space available on it, so moving down to a 4-40 there to complete that part of the circuit was necessary.
Now it's time to drill blind clearance holes for the 3/16" support rods that keep the unit in alignment....
Y axis is moved into position followed by another touch-off and zeroing of the drop-down indicator before drilling.
I have found that for whatever reason, the USA made cobalt drills sold at enco cut the smoothest in acetyl compared with other reasonably priced cutters. One would think that any HSS cutter would work great, but after having experimented with many different drill bits, I've come to the conclusion that that there is something "different" about the way that these bite the plastic. I doubt it has anything to do with it being cobalt, probably more to do with the way the tip is ground.
Here we are plunging to the proper depth for these blind holes under high RPM and feed. Lots of quick "pecking" of the drill to pull out material works best.
The regulator is held in place, given room for surface mount parts, and makes electrical contact to the top plate through 4-40 male-female stand-off screws. These are positioned in alignment with the support rods of the adapter. A through-hole is drilled in down through the remaining plastic in the bottom of each of the support-rod holes.
That same drill is then used to drill a center hole and that one battery contact I mentioned previously.
This part is basically finished!
Another 9 part just like this one are made, and then 10 parts for the other side are made. The other main body part of the adapter is very similar to this as far as the operations go so I didn't take any more pictures for that.
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During operations on each part, numerous tool changes are often required. Each tool is loaded into a collet holder on a straight shank that is held into the machine by a common size collet loaded into the spindle of the machine. The collet in the machine stays the same for all of the tool change operations here. A Length of 2x4 that has holes drilled from the side has been attached to the front of the table where the mill sits. Tools are loaded from right to left in the order I will be using them (they aren't really in order in the picture below but you get the idea). I use my left hand to fetch and return tools from this tool "tray" and my right hand to operate the draw bar tool. I've converted the draw bar tool into a combination socket driver and soft hammering instrument with a sleeve of delrin.
This type of tool changing ability is crucial to production work.
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After using the zombie killer to size up all those parts, and then using the 17mm end mill to remove the majority of the plastic, the area around the mill starts to look like one of those snow globes just before you shake it up...
Air compressor, combined with one of THESE (see below) is absolutely ideal for blasting off the table and getting all of those chips up and out of the indexing table and mill table.
After the chips are all on the floor I hit it with the shop-vac. I have one of those little 8 gallon shop-vacs, milling a good 20-40 parts will pretty much fill it up with chips.
Milling operations tend to leave a bit of "fray" around the edges. It's hard to get it all cleaned up in the pockets, but I take about a minute or two per piece with the razor and get it cleaned up as best as possible.
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Here's how I make the tailcap "thumb nut" assembly.....
The 1.25" diameter wafer of plastic is mounted up, and then I use that handy favorite 2 flute 5/16" carbide cutter to plunge a hole right through the center, then use the X-axis to go off center a bit, then rotate the table around to get just the right size hole. (about 0.350). You might ask; "why not just use the right size bit?" That would be a great question! The answer is of course obvious: I keep forgetting to order that size bit (up until now, this process has more than sufficed for making prototypes). Good news is, I've ordered the proper size bit, it will be here before I do the next batch.
Now I'm just going to take some knurled brass thumb nuts, and press fit them into that hole very gently with a very hard smack of the hammer! I use that short piece of delrin scrap as a punch tool
Pretty nifty eh?
Now lets give these modified thumb nuts some grip:
It's a pretty simple plunge operation.
Razor knife used again to clean these up.
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On the main body part opposite the one that holds the regulator; the one that the thumb nut assembly shown above fits into, I have to mill a pocket for the thumb nut and electrical connection to the pack termination.
In order to perform a cutting operation on the other side of a part (part flipping), the part must be re-indexed. I use a center finder (wiggler) and one of the holes that was previously drilled for the battery contacts to get the part into position.
You can see the goal of this operation in the part that is more in the foreground in this picture.
Now that all of the milling and drilling operations on the main body parts are completed, I can go ahead and tap the holes for screws and standoffs and the center rod and such...
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For the next set of operations, I need the other side of the soft jaws... I'll explain in a moment....
Removing the jaws and turning them around...
When tightening, I try to go back and forth from one to the other bolt that holds them down. The jaws shimmy there way down into place with the least possible wear this way.
A final snugging up of the socket drive bolts is performed with the same tool that I use on the draw bar. (neat coincidence eh?)
After any time I swap jaws or swap the way they are mounted, I always like to double check that zero is still zero....
Nice and smooth on the side of the center finder, zero is still zero. Good stuff.
The reason I need the other side of the jaws for this next operation has to do with the way that the bottom shelf is cut with these reliefs that allow for a cutting tool to be very close to the jaw face on a through-hole there.
Drilling a center hole:
A finished part can be seen sitting to the side there.
touch-off and zero out with that very popular carbide cutter:
cutting the slot.
Drilling clearance holes for the screws that hold this top piece down onto the standoffs. The one screw in the slow makes up part of the circuit, the other 2 are just to keep things in place.
The other 2 holes just need to be countersunk so that the screws that hold this part down are not exposed above the surface. I'm using a 1/4" center cutter for this.
Zero it out first... Then plunge to proper depth.
(looks like the end mill is touching the jaw, I assure you, there is at least 0.020" clearance! hehe)
The next operation is sort of a neat trick. I need a hole cut out to give access to the dip switches that allow the user to adjust the voltage settings.
Carbide 3 flute center cutting 1/8" tool here....
The part is about 0.180 thick. I do 2 separate passes for the cutout to split up the load between cuts.
After the second pass, I come back and do a third finishing pass taking off a few more thou to clean up the hole.
The part is now flipped and re-indexed. Several countersinks are required on the bottom side here. (as pictured)
This is why I don't like using 4 flute cutters for plunge milling.... (I have a 2 flute carbide coming in the mail, along with that bit mentioned above!)
At this point, pretty much all of the important plastic machine work is done. Time to populate these parts with brass and copper.
Electrical contacts are cut and punched from copper sheet.
Have to pull back the protective plastic.....
I then mark and draw lines where I want cuts and punches to take place..
The lines remaining on these pieces represent the location that holes need to be punched.
Using the calipers, I scribe the position on the end of the strip where I need to cut again.
Scribe, Cut, Scribe, Cut, etc etc....
Punching holes is tricky. Hard to see where the punch is going to land without plenty of light. I usually wear my headlamp for this. Wow, looks like I spent a lot of time on my hair there eh?
Myself intently focusing on landing that hole!
The results:
Some of the copper part need a little crescent shape cut out of the side of them so they don't short against the center rod of the adapter. I have a trick for this, but need to swap the jaws again...
This is one of the punch inserts for those hand tools being installed in the collet/tool holder.
The female portion of the punch is clamped into the hard jaws.
This makes this part of the operation pretty painless..
You can see here where that little cutout comes into play.
Now the copper parts need to be sized down and trimmed up nice to fit in the various recesses and pockets around the adapter....
Doing the top (regulator cover) part first. The 6-32 x 5/16" brass nut will serve as the negative output of the adapter. The slot is purposely cut 5/16" wide so that the nut is held firmly in place as a screw is driven in from the other side.
Moving on to the bottom piece of the adapter, same method is used here. The nut is 5/16" and the slot is as well.
All done!
Now installing the contacts that connect the cells in series within the pack.
On the other end of the pack, the regulator interfaces with the pack via this 4-40 screw.
The rest of the contacts are installed (not pictured) and we are moving along....
Swapping back to the soft jaws again...
So we can do THIS!
The screw heads are milled down to a nice looking "contact" pad.
I used to side-mill this operation, until I found an end-mill that would plunge it without having problems. Had to be carbide, but now that I found it, these contacts are coming right off the cutter with a neat finish that looks great.
All of the battery contact pads have now been milled down. Don't they look beautiful?
The part that covers the regulator and has one of the final external contacts for the adapter also needs some touch up work....
The Bottom piece of the adapter, where the thumb nut rides on, also need to have the excess screw there whacked off so that the thumb nut can spin freely without interference.
Things are starting to take shape here nicely eh....
Now I need to cut the center threaded rod that holds the unit together, and also acts as the V-sense circuit path for the regulator.
Picked up these cutters on a grand opening sale at a new Ace Hardware store that opened up a few months back. 50% off. $8 IIRC. Very handy tool.
After the cut, the end is pretty smeared up so to speak and the threads at the tip are destroyed.
The bench grinder is used to clean up both ends of each rod.
After spinning the rods between my fingers as they are gently pressed into the grinding wheel, I'll often give it a quick touch to the wire wheel while spinning in the fingers. This will remove any significant burs left behind by the grinding wheel.
Check for length, then do additional grinding if it's too long. (I always cut slightly over-size).
Even after grinding and cleaning, the first thread is always very slightly distorted and can cause a bit of binding on a nut. I gently clamp it into the vise...
Then just spin this die over the tip of both ends of the rod by hand. Pushing and pulling on the die a little as I go. This shapes up those last few threads pretty well.
When the rod is ready, I install it into the body part that the regulator sits on top of. The center hole is purposely only tapped part way through, the last few threads will bind into un-threaded plastic. This is by design and prevents the rod from being inadvertently spun out of position by any friction in the thumb nut assembly. I use a pair of plyers to hold the rod and then spin the body part by hand over the rod.
I need enough rod sticking up for the thickness of the regulator, a washer, and a stainless steel small pattern nut. This should do just fine...
The threaded rods are now all installed:
Another milling operation is needed here. On the top piece that covers the regulator, we need a recessed pocket for a serial number to be put on the unit for future identification. Will is coming up with a method to label each unit so that in the future, there will be a way to track which regulator setting are programmed on that particular unit.
Clamp the part in place (these are just eye-balled, no need for this to be located about the axis with any great precision) Start with running the Y axis out from center into position. Then the X axis off center to the appropriate position. Touch-off and zero out the Z axis DRO.
About to fire it up in this photo. You can see the intended results in the part sitting to the side.
Plunge to the proper depth, crank hand-wheel...
I go one direction for each part to save on time. Where the cut ends on one part, it begins on the next part.
All done with that now.
The adapter is supported by 3 rods that run the length. They are 3/16" diameter delrin. These rods keep the ends of the adapter in alignment at all times. Also, they give the unit natural rigidity whether the cells are loaded or not. Here I'm getting lined up to cut a bunch of them. The piece of scrap 2x4 is pushed against the rods during the cut right up next to where the cut is taking place to prevent the rods from vibrating and just breaking rather than cutting smoothly.
Install the rods and check for proper length (I test fit cells at this point).
Below are some of the fasteners that Will is going to use to attach the regulator and cover piece for the regulator.
Install rods in all units....
Then install the bottom body piece, being careful to align it properly to produce a series connection between the cells. Then spin on the thumb nuts for each unit..
Since Will would have to remove the top cover piece in order to install the regulator, I'm not going to install that on all of the units. I'll just do one here to show as an example. (I'll be sending a baggy full of the top pieces and fasteners for him to play with there)...
Each point of contact with the regulator has a small stainless steel washer, this reduces the chance of damaging the regulator with the hex fasteners.
Standoffs are installed around the perimeter. A SS nut is used in the center (there is no current flow here, this connection is purely for the regulator to measure the voltage), and a brass nut is used on the negative contact to the pack. The brass will have lower resistance, this is a current carrying contact.
Stainless Steel button top hex drive machine screws are used to hold the top cover in place. One of them completes the circuit from one of the stand-offs to the center output of the adapter.
Pretty neat eh?
Still not done. We need to mark the slots for polarity so that cells get installed correctly....
This operation is done with a small center cutting end mill, I just eye-ball a position on the side of the adapter at the end of each slot and plunge a little flat bottom hole there. The adapter isn't even clamped down. This cutting operation is very low load, Using the milling vise with the jaws opened up just enough for the unit to sit down in there (but not all the way down) helps keep 2 axis of motion held in place plenty well. I just hold the end of the unit with my fingers and push down during the cut.
The goal of the operation can be seen in the left most unit in this picture. Fine point sharpies are used to fill in the little holes with color to indicate polarity.
All Done!!!
For those not familiar, this is a 3x17670 adapter for the SureFire M6 built in collaboration with CPF member WQuiles (Will). Will has been working on a regulator and I have been building the adapter to support that regulator and cells. The project has been in the works with the help of several other CPF members for a long time now. We are coming close to releasing units and this is a picture story line that covers the building of the adapters themselves. After these adapters are completed, they will be sent to Will to have the drivers built, installed, programmed and calibrated. You can see that proccess in this thread here!
The PhD project was actually what motivated me to get a Mill. I really wanted to be a part of this project, and while it has been a long time coming, that time has not been a waste at all. It has given me the time to practice on the machine and develop other products on it and get a feel for what can be done. This adapter represents the "latest and greatest" of my abilities with the equipment I have.
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The adapters are made primarily from acetyl plastic round rod stock. Here I am cutting pieces of 1.5" diameter to the appropriot length plus some over-size for the main portions of the body. Each adapter consists of 3 pieces cut from 1.5" rod, and a single small piece cut from 1.25" diameter rod to make the "tailcap" thumb nut.
A 10" 15Amp miter saw with a finishing blade (normally for use on wood) works great in most non-reinforced plastics. I've been using this same blade on this same miter saw since I started Odd Mods over 2 years ago. Still cuts like a champ. As many of you know, I often look for bargains on tools, sometimes it bites me but usually it works out pretty well. The miter saw was purchased on "Black Friday" at Lowes for $60 (marked down from $100).
For the first batch of PhDs, I am just doing 10 units. Best to start with small batches to work out any hitches in production before moving on to larger batches. Next thing on my list of things to get is some decent stack-able plastic bins to put parts like this in. I have been using small boxes like this for a long time. I keep getting more boxes as I order supplies and tools so there is a never ending supply of them it seems.
Before I get started machining parts. I like to figure out all of the cutting tools I am going to need for the project and pre-load as many as possible into the ER25 collet holders. Doing this now before chips and plastic "dust" starts flying means a lot less hassle. I give all the mating surfaces of the collet and collet holder a quick wipe with my hands to remove any debris.
All of the plastic pieces that were cut on the saw are over-sized in all dimensions from what I actually need. The saw does not cut to precision anyways, and it's rarely a perfectly straight cut. The Mill will be used with the 2" 6 flute end mill to square up and size up the parts before they start to take shape. Whacking off the top and bottom of each piece to first square it up, followed by a final cut to size is the proceedure I often use. However, this means a ton of cranking the hand wheel on the X-axis of the mill. I was going to buy the Power Feed for the X3 series of Mills, but after reading about them, I've decided against it. (apparently, they do not disengage the motor from the lead screw when turned off, so precision manual work on the X-axis becomes very difficult). For now, I've custom cut a "driver-bit" of sorts from delrin that fits in the 1/2" chuck of the Ryobi cordless drill. It's essentially a big flat-head/block drive.
It works really well by the way! I run about half throttle on the drill in high gear with the mill turning at about 2kRPM. About 50-60IPM by my calculations.
Using the Ryobi works so well for my purposes that I have decided to build a power feed from a cordless drill and computer power supply. I picked up a Dewalt 12V cordless without any working batteries from craigslist for $10 the other day. This project will have to wait till another day, but I think it will work very well when it's all said and done. I'll probably just use the transmission that is attached to the motor and basically just build up a mount for the guts of the drill to hold it out off the end of the table. The clutch will be set a few notches down from "drill" mode to act as a sort of safety measure (since I probably won't bother with kill switches on stops).
Sorry, I'm getting a little off topic there....
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Here we are removing some plastic off and showing it who's boss.
When tightened, the jaws "straighten up" the part to within about a thou across the surface. I don't need it absolutely perfectly square, but within a thou or 3 from the thickest to thinnest part of the "wafer" is nice.
The thinner parts pictured below can't sit down deep in the jaws. I have a shallow step cut out of these jaws just for this type of part size. Since the diameter also will need to be taken down, these thinner parts will only be squared up for now. I need enough material remaining to be able to flip the part and mill down the diameter from both sides. (there are other ways this could be done but so far I like this one)...
These shots we taken with the flash, so the exposure time is very short, the mill is spinning pretty fast, but it looks like I've managed to catch it "in it's tracks" on these shots.
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Now that we have squared up these parts. It's now time to take down the diameter. The top part will be "turned" down to about 1.435"
Before I tell you this next part. Do as I say, not as I do:
I say the following: For turning down parts on a Mill like this, buy a rotary table with a worm drive or at least some kind of hand-crank wheel.
I do the following: The indexing table is turned by hand. This is quick and easy but requires that you pay attention to what the heck is going on. Keeping fingers clear of the zombie killer (nick name for 2" end mill) is absolutely critical and I would never advise that anyone perform this operation. I happen to trust myself and have been turning down plastic parts like this for over a year without a single close call.
Now the larger pieces...
Flip the part, repeat..
As I had mentioned before. I require the additional thickness be left behind on these thinner pieces to have enough available to turn them down and still have material to clamp on to. So now I come along and take that final cut to size up the part.
After sizing up all of the parts. I have a nice pile of plastic wafers that still look pretty baron.. Time to give them some character!
Carefully put the zombie killer away!
Usually after running the X-axis back and forth that many times, I'll put the center finder in the machine and make sure that my zeroed out center position of the indexing table is still in tune.
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Time to take the first cut.
Insert 17mm center-cutting 2 flute end mill into machine. (plunging operations work best with 2 flute cutters in my experience).
Touch off on surface and "zero" out the drop-down indicator.
Move Y axis into position for the first cut.
Plunge cut to the proper depth (minus a bit)
After plunging the cutter every 120 degrees about the part, the Y axis is moved out a little further and the plunging is repeated in each position. This relieves enough material from what will be the battery slots to perform a final plunge and side-milling operation to clean out the slot.
After those steps are complete, we have a part that is starting to look like something....
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Now I install a 5/16" solid carbide center-cutting 2 flute end mill into the machine.
Then I touch down and zero out down in the pockets I milled previously.
Sorry about the over-exposed shots here...
This end mill is used to both clean out the center "tower" of plastic that was left behind by the large cutting operation of the 17mm cutter. after which point, it is moved into position to make a shallow slot cut that the copper "bridge" used for completing the series electrical path between the batteries can be countersunk into.
The battery contacts in the adapters are made from (primarily) 6-32 brass screws located in the center of each "pocket." Holes are drilled (to be tapped later) to accommodate these screws. After cutting the slow pictured above, I re-find center on the X-axis and then move the Y axis out to the position where these holes need to be drilled.
Since I am working on the end of the adapter that the regulator sits on, one of those holes is actually drilled to accommodate a 4-40 size screw. The regulator needed every bit of space available on it, so moving down to a 4-40 there to complete that part of the circuit was necessary.
Now it's time to drill blind clearance holes for the 3/16" support rods that keep the unit in alignment....
Y axis is moved into position followed by another touch-off and zeroing of the drop-down indicator before drilling.
I have found that for whatever reason, the USA made cobalt drills sold at enco cut the smoothest in acetyl compared with other reasonably priced cutters. One would think that any HSS cutter would work great, but after having experimented with many different drill bits, I've come to the conclusion that that there is something "different" about the way that these bite the plastic. I doubt it has anything to do with it being cobalt, probably more to do with the way the tip is ground.
Here we are plunging to the proper depth for these blind holes under high RPM and feed. Lots of quick "pecking" of the drill to pull out material works best.
The regulator is held in place, given room for surface mount parts, and makes electrical contact to the top plate through 4-40 male-female stand-off screws. These are positioned in alignment with the support rods of the adapter. A through-hole is drilled in down through the remaining plastic in the bottom of each of the support-rod holes.
That same drill is then used to drill a center hole and that one battery contact I mentioned previously.
This part is basically finished!
Another 9 part just like this one are made, and then 10 parts for the other side are made. The other main body part of the adapter is very similar to this as far as the operations go so I didn't take any more pictures for that.
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During operations on each part, numerous tool changes are often required. Each tool is loaded into a collet holder on a straight shank that is held into the machine by a common size collet loaded into the spindle of the machine. The collet in the machine stays the same for all of the tool change operations here. A Length of 2x4 that has holes drilled from the side has been attached to the front of the table where the mill sits. Tools are loaded from right to left in the order I will be using them (they aren't really in order in the picture below but you get the idea). I use my left hand to fetch and return tools from this tool "tray" and my right hand to operate the draw bar tool. I've converted the draw bar tool into a combination socket driver and soft hammering instrument with a sleeve of delrin.
This type of tool changing ability is crucial to production work.
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After using the zombie killer to size up all those parts, and then using the 17mm end mill to remove the majority of the plastic, the area around the mill starts to look like one of those snow globes just before you shake it up...
Air compressor, combined with one of THESE (see below) is absolutely ideal for blasting off the table and getting all of those chips up and out of the indexing table and mill table.
After the chips are all on the floor I hit it with the shop-vac. I have one of those little 8 gallon shop-vacs, milling a good 20-40 parts will pretty much fill it up with chips.
Milling operations tend to leave a bit of "fray" around the edges. It's hard to get it all cleaned up in the pockets, but I take about a minute or two per piece with the razor and get it cleaned up as best as possible.
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Here's how I make the tailcap "thumb nut" assembly.....
The 1.25" diameter wafer of plastic is mounted up, and then I use that handy favorite 2 flute 5/16" carbide cutter to plunge a hole right through the center, then use the X-axis to go off center a bit, then rotate the table around to get just the right size hole. (about 0.350). You might ask; "why not just use the right size bit?" That would be a great question! The answer is of course obvious: I keep forgetting to order that size bit (up until now, this process has more than sufficed for making prototypes). Good news is, I've ordered the proper size bit, it will be here before I do the next batch.
Now I'm just going to take some knurled brass thumb nuts, and press fit them into that hole very gently with a very hard smack of the hammer! I use that short piece of delrin scrap as a punch tool
Pretty nifty eh?
Now lets give these modified thumb nuts some grip:
It's a pretty simple plunge operation.
Razor knife used again to clean these up.
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On the main body part opposite the one that holds the regulator; the one that the thumb nut assembly shown above fits into, I have to mill a pocket for the thumb nut and electrical connection to the pack termination.
In order to perform a cutting operation on the other side of a part (part flipping), the part must be re-indexed. I use a center finder (wiggler) and one of the holes that was previously drilled for the battery contacts to get the part into position.
You can see the goal of this operation in the part that is more in the foreground in this picture.
Now that all of the milling and drilling operations on the main body parts are completed, I can go ahead and tap the holes for screws and standoffs and the center rod and such...
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For the next set of operations, I need the other side of the soft jaws... I'll explain in a moment....
Removing the jaws and turning them around...
When tightening, I try to go back and forth from one to the other bolt that holds them down. The jaws shimmy there way down into place with the least possible wear this way.
A final snugging up of the socket drive bolts is performed with the same tool that I use on the draw bar. (neat coincidence eh?)
After any time I swap jaws or swap the way they are mounted, I always like to double check that zero is still zero....
Nice and smooth on the side of the center finder, zero is still zero. Good stuff.
The reason I need the other side of the jaws for this next operation has to do with the way that the bottom shelf is cut with these reliefs that allow for a cutting tool to be very close to the jaw face on a through-hole there.
Drilling a center hole:
A finished part can be seen sitting to the side there.
touch-off and zero out with that very popular carbide cutter:
cutting the slot.
Drilling clearance holes for the screws that hold this top piece down onto the standoffs. The one screw in the slow makes up part of the circuit, the other 2 are just to keep things in place.
The other 2 holes just need to be countersunk so that the screws that hold this part down are not exposed above the surface. I'm using a 1/4" center cutter for this.
Zero it out first... Then plunge to proper depth.
(looks like the end mill is touching the jaw, I assure you, there is at least 0.020" clearance! hehe)
The next operation is sort of a neat trick. I need a hole cut out to give access to the dip switches that allow the user to adjust the voltage settings.
Carbide 3 flute center cutting 1/8" tool here....
The part is about 0.180 thick. I do 2 separate passes for the cutout to split up the load between cuts.
After the second pass, I come back and do a third finishing pass taking off a few more thou to clean up the hole.
The part is now flipped and re-indexed. Several countersinks are required on the bottom side here. (as pictured)
This is why I don't like using 4 flute cutters for plunge milling.... (I have a 2 flute carbide coming in the mail, along with that bit mentioned above!)
At this point, pretty much all of the important plastic machine work is done. Time to populate these parts with brass and copper.
Electrical contacts are cut and punched from copper sheet.
Have to pull back the protective plastic.....
I then mark and draw lines where I want cuts and punches to take place..
The lines remaining on these pieces represent the location that holes need to be punched.
Using the calipers, I scribe the position on the end of the strip where I need to cut again.
Scribe, Cut, Scribe, Cut, etc etc....
Punching holes is tricky. Hard to see where the punch is going to land without plenty of light. I usually wear my headlamp for this. Wow, looks like I spent a lot of time on my hair there eh?
Myself intently focusing on landing that hole!
The results:
Some of the copper part need a little crescent shape cut out of the side of them so they don't short against the center rod of the adapter. I have a trick for this, but need to swap the jaws again...
This is one of the punch inserts for those hand tools being installed in the collet/tool holder.
The female portion of the punch is clamped into the hard jaws.
This makes this part of the operation pretty painless..
You can see here where that little cutout comes into play.
Now the copper parts need to be sized down and trimmed up nice to fit in the various recesses and pockets around the adapter....
Doing the top (regulator cover) part first. The 6-32 x 5/16" brass nut will serve as the negative output of the adapter. The slot is purposely cut 5/16" wide so that the nut is held firmly in place as a screw is driven in from the other side.
Moving on to the bottom piece of the adapter, same method is used here. The nut is 5/16" and the slot is as well.
All done!
Now installing the contacts that connect the cells in series within the pack.
On the other end of the pack, the regulator interfaces with the pack via this 4-40 screw.
The rest of the contacts are installed (not pictured) and we are moving along....
Swapping back to the soft jaws again...
So we can do THIS!
The screw heads are milled down to a nice looking "contact" pad.
I used to side-mill this operation, until I found an end-mill that would plunge it without having problems. Had to be carbide, but now that I found it, these contacts are coming right off the cutter with a neat finish that looks great.
All of the battery contact pads have now been milled down. Don't they look beautiful?
The part that covers the regulator and has one of the final external contacts for the adapter also needs some touch up work....
The Bottom piece of the adapter, where the thumb nut rides on, also need to have the excess screw there whacked off so that the thumb nut can spin freely without interference.
Things are starting to take shape here nicely eh....
Now I need to cut the center threaded rod that holds the unit together, and also acts as the V-sense circuit path for the regulator.
Picked up these cutters on a grand opening sale at a new Ace Hardware store that opened up a few months back. 50% off. $8 IIRC. Very handy tool.
After the cut, the end is pretty smeared up so to speak and the threads at the tip are destroyed.
The bench grinder is used to clean up both ends of each rod.
After spinning the rods between my fingers as they are gently pressed into the grinding wheel, I'll often give it a quick touch to the wire wheel while spinning in the fingers. This will remove any significant burs left behind by the grinding wheel.
Check for length, then do additional grinding if it's too long. (I always cut slightly over-size).
Even after grinding and cleaning, the first thread is always very slightly distorted and can cause a bit of binding on a nut. I gently clamp it into the vise...
Then just spin this die over the tip of both ends of the rod by hand. Pushing and pulling on the die a little as I go. This shapes up those last few threads pretty well.
When the rod is ready, I install it into the body part that the regulator sits on top of. The center hole is purposely only tapped part way through, the last few threads will bind into un-threaded plastic. This is by design and prevents the rod from being inadvertently spun out of position by any friction in the thumb nut assembly. I use a pair of plyers to hold the rod and then spin the body part by hand over the rod.
I need enough rod sticking up for the thickness of the regulator, a washer, and a stainless steel small pattern nut. This should do just fine...
The threaded rods are now all installed:
Another milling operation is needed here. On the top piece that covers the regulator, we need a recessed pocket for a serial number to be put on the unit for future identification. Will is coming up with a method to label each unit so that in the future, there will be a way to track which regulator setting are programmed on that particular unit.
Clamp the part in place (these are just eye-balled, no need for this to be located about the axis with any great precision) Start with running the Y axis out from center into position. Then the X axis off center to the appropriate position. Touch-off and zero out the Z axis DRO.
About to fire it up in this photo. You can see the intended results in the part sitting to the side.
Plunge to the proper depth, crank hand-wheel...
I go one direction for each part to save on time. Where the cut ends on one part, it begins on the next part.
All done with that now.
The adapter is supported by 3 rods that run the length. They are 3/16" diameter delrin. These rods keep the ends of the adapter in alignment at all times. Also, they give the unit natural rigidity whether the cells are loaded or not. Here I'm getting lined up to cut a bunch of them. The piece of scrap 2x4 is pushed against the rods during the cut right up next to where the cut is taking place to prevent the rods from vibrating and just breaking rather than cutting smoothly.
Install the rods and check for proper length (I test fit cells at this point).
Below are some of the fasteners that Will is going to use to attach the regulator and cover piece for the regulator.
Install rods in all units....
Then install the bottom body piece, being careful to align it properly to produce a series connection between the cells. Then spin on the thumb nuts for each unit..
Since Will would have to remove the top cover piece in order to install the regulator, I'm not going to install that on all of the units. I'll just do one here to show as an example. (I'll be sending a baggy full of the top pieces and fasteners for him to play with there)...
Each point of contact with the regulator has a small stainless steel washer, this reduces the chance of damaging the regulator with the hex fasteners.
Standoffs are installed around the perimeter. A SS nut is used in the center (there is no current flow here, this connection is purely for the regulator to measure the voltage), and a brass nut is used on the negative contact to the pack. The brass will have lower resistance, this is a current carrying contact.
Stainless Steel button top hex drive machine screws are used to hold the top cover in place. One of them completes the circuit from one of the stand-offs to the center output of the adapter.
Pretty neat eh?
Still not done. We need to mark the slots for polarity so that cells get installed correctly....
This operation is done with a small center cutting end mill, I just eye-ball a position on the side of the adapter at the end of each slot and plunge a little flat bottom hole there. The adapter isn't even clamped down. This cutting operation is very low load, Using the milling vise with the jaws opened up just enough for the unit to sit down in there (but not all the way down) helps keep 2 axis of motion held in place plenty well. I just hold the end of the unit with my fingers and push down during the cut.
The goal of the operation can be seen in the left most unit in this picture. Fine point sharpies are used to fill in the little holes with color to indicate polarity.
All Done!!!
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