10x 18650 in a 6D Mag

[B30wuLF]

i am planning a 3xP7 Mag with wichtel´s kit.

putting just 5 18650 in a 6D Mag seems like a waste of space to me. is it possible to bore out the tube to fit 2x 18650 side by side? i ve seen this done with shorter mags here (thread) but it this possible with a 6d tube? and how?

 

[precisionworks]

One method come to mind, but I've have not tried it

Set the tube vertically in the mill & bore each of the three partial circles. To make this work on a long, thin, flexible part (like a Mag tube) would require boring a set of soft jaws to support the tube. A piece of aluminum square stock, 3"x3" and as long as the tube, would be bored to the OD of the Mag tube & split on the long dimension.

Bolt an angle plate to the mill table, one that's as tall as the tube, and clamp the tube-in-soft jaws to the angle plate with step clamps. Center the tube under the spindle & move the table so that the cutter engages the correct amount of the wall. An extra length solid carbide end mill, .750" diameter, will give a radius just slightly larger than the 18650. Plunge mill one slot & move the table as needed for the second & third slot (either by trigging out the moves or using the bolt circle calculator in a DRO).

If the tube is longer than the total end mill projection, the tube will need to be inverted to complete each cut - if the soft jaws are clamped to the tube before inverting it, there should be no registration problem.

This is not a fast job :nana:

 

[Benson]

I've never seen an endmill long enough to do halfway down a 6D Mag -- I'd have to go with a between-centers boring-bar, if I were to try it.

But assuming you want to do a Mag body in a Bridgeport, I'd drop the angle plate and just bolt the jaws+flashlight assembly to the front of the table, using the travel stop T-slot. Slew the head over, and you're good to go -- I've used this trick a couple times with a V-block to do end work on long shafts.

 

[precisionworks]

I'd have to go with a between-centers boring-bar

+1

A large diameter, solid carbide boring bar would be another option, using either a positive rake free machining insert or a negative rake high positive aluminum insert. Boring bars are readily available in 3/4" diameter, which allows boring roughly 7.5" (10 diameters), but cheap they are not ... roughly $500 retail, although there are a few on eBay for around $200:

http://cgi.ebay.com/ws/eBayISAPI.dl...f75474e&itemid=270507967769&ff4=263602_263622

Even though the bar will allow boring 7.5", no mill that I know of has more than 5" of down travel in the quill. Which means setting this up on a knee mill, snugging down the knee gibs, tramming the head dead nuts, bringing the quill down until the boring bar starts to cut, and raising the knee until the boring head almost touches the end of the Mag tube. Some Bridgeports (newer ones especially) do a decent job when raising the knee into the cutter, but the knee is almost always less accurate than the quill - it's a case of gibs versus ABEC-7 bearings, and the bearings always win

I've used this trick a couple times with a V-block to do end work on long shafts.

+1

I've done that also, using my largest V-blocks (4" or 5" length of V).

 

[precisionworks]

never seen an endmill long enough to do halfway down a 6D Mag

Quite a few companies make them and they have about the same reach as a boring bar of equal diameter. Price is always an issue in solid carbide, this one is "only" $297

http://www.harveytool.com/products/...0&category_id=1&product_family=Ball+End+Mills

 

[alpg88]

that sounds like an awesome light in the making.
i'm making 6 18670 light from Der Wichtel kit, myself.
i sent 4d mag for dualborring to j. Hernandez, he did a great job.
i build a holder for 3s2p 18650, but i wont be using his driver, cuz voltage is too low for it to work, it'll be direct drive and possibly i'll use diode, or not, i think my holder has enough resistance not to use, (my 20w mr 16 pulling 1,5 amp at the tail) i'm still waiting on p7's, for now i use 20w mr16, it is temp solution just to test my holder.

as for borring if you don't have equipment, my advice sent it to someone that does, it will cost you but it will be worth it,
18650 you can fit only 2 side by side, 17670 you can fit 3.

 

[65535]

Might be a job for broaching.

 

[B30wuLF]

this was my initial idea too.
bulding a tool from a rod that fits the id of the mag tube and has a round indexable insert on one end. then the rod has to be cut and fit with some kind of mechanism to make the cut wider => pressure on the indexable insert.

fyi: i did a quick and dirty ProE model of the 10x18650 assemly.
the red parts are made from copper. the plate at the negative terminal has two aa light springs (yellow) and a wire directly to the driver.

 

[gallonoffuel]

+1

A large diameter, solid carbide boring bar would be another option, using either a positive rake free machining insert or a negative rake high positive aluminum insert. Boring bars are readily available in 3/4" diameter, which allows boring roughly 7.5" (10 diameters), but cheap they are not ... roughly $500 retail, although there are a few on eBay for around $200:

http://cgi.ebay.com/ws/eBayISAPI.dl...f75474e&itemid=270507967769&ff4=263602_263622

Even though the bar will allow boring 7.5", no mill that I know of has more than 5" of down travel in the quill. Which means setting this up on a knee mill, snugging down the knee gibs, tramming the head dead nuts, bringing the quill down until the boring bar starts to cut, and raising the knee until the boring head almost touches the end of the Mag tube. Some Bridgeports (newer ones especially) do a decent job when raising the knee into the cutter, but the knee is almost always less accurate than the quill - it's a case of gibs versus ABEC-7 bearings, and the bearings always win

+1

I've done that also, using my largest V-blocks (4" or 5" length of V).

I wish I knew what any of that meant. That was all in English, right?


I have a lot to learn

 

[StrikerDown]

Outside the box and probably a silly idea, but I wonder if cutting flutes could be milled or ground into a sufficiently long shaft of drill rod or HSS, run the new cutting shaft inside the tube between centers on a lathe and use the cross slide with the tube clamped to if for controlling the feed?

:huh:

 

[gadget_lover]

That is similar in concept to line boring. It is easily done with a cutting bit in the middle of a long (and stiff) rod that is between centers.

Daniel

 

[Fred S]

I am with gadget on this one. Clamp the mag body to the cross slide or tool post. Put a single point bit in the middle of a bar that is about 2 x as long as the body. run the bar between centers and run the carraige left/right with the power feed. Move the cross slide in to increase depth of cut.

 

[precisionworks]

I wish I knew what any of that meant. That was all in English, right?

I really do try to keep it simple, but some operations require more than a quick & dirty set up. I said (sort of) that there is not enough down travel in the spindle to bore as far as needed. The other option - on a knee mill - is to use the spindle to lower the boring bar to the part & then feed the knee upward into the boring bar. A Bridgeport milling machine has 16" of knee travel (aka Z axis), which would allow boring a part 16" long if the boring bar was longer than that.