Tritium slot machining

[precisionworks]

Received a TnC titanium P60 host, V1 head & anti roll tail. The light came with six 1.5x5mm slots in the tail & eight 1.5x5mm in the head. I emailed the owner to let him know that I was about to start installing his fourteen trits & he asked if there might be room for fourteen more

It's a good sized host so there's lots of room. He also decided to add three more 2x6mm vials in the raised section of the tail.

Finishing up one of the tail slots. Tail is mounted on a 5C expanding arbor that grips from the inside. When carefully machined these arbors have less than 0.01mm run out & that means all the slots are identical in depth, +/- 0.01mm:



Dry fitting a 2x6mm vial to make sure the slot depth is correct - 2.0mm for the vial plus 0.2mm more so the vial seats slightly below flush:

[Mattaus]

I need better lights so I can get this sort of work done to them...but I also need more cash

One day

[precisionworks]

Snapped my last 1.5mm end mill during test cuts yesterday but Red Label (early delivery) UPS came to the rescue

IMO the most interesting slotting jobs are those that involve matching existing slots. One has to reverse engineer the setup used by the prior machinist & then exactly duplicate those parameters. Let's see ... hang out the "closed" sign, lock the shop door, select a good station on internet radio & go to work. A friend of mine is a sky diver & says that the most exhilarating moment is not the free fall but rather the milliseconds that elapse between pulling the ripcord & waiting for the chute to deploy. That's how I feel when making the very first touch off cut

This complex method is used to keep track of indexing moves:



Finishing the first slot (the other two slots were already milled at TnC):



Testing for depth & fit (slot with trit is the "new" one):



Looks to me like it was there all along & that's what has to happen. Total time to set up & mill the first slot - 120 minutes. The remaining five slots will not take as long.

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UPDATE: Laced up my running shoes and blitzed through the last five slots in only 75 minutes. Counting setup time that comes out to 32.5 minutes/slot. I need to raise my rates

[dbleznak]

That is incredible !!!!!

[precisionworks]

That is incredible !!!!!

Thank you for your kind words Dan

Had planned to set the tail trits in Norland after dinner but SWMBO had other ideas. Trits go in first thing tomorrow but here's the finish milled tail:



Same setup with slightly different lighting:



IMO the additional slots add more visual balance to the tail. Always a pleasure to work with anything TnC, whether aluminum or titanium, as the machining is so well executed.

[jhanko]

This complex method is used to keep track of indexing moves:

That's funny. I used to do a very similar thing. I got tired of it, so I made a simple spreadsheet that I printed out and taped it on the wall next to the mill. It's really convenient and saves time. You're welcome to it if interested. It prints out on 2 landscape pages, then tape them together. This way it's big enough to see at a distance. I stopped at 16, as I figured if someone wants more than 16 vials on a flashlight's circumference, they need a Psychiatrist, not a machinist...

[precisionworks]

... I figured if someone wants more than 16 vials on a flashlight's circumference, they need a Psychiatrist, not a machinist...

ROFLMAO

I am interested in your Excel spreadsheet - would you email that?

The most interesting one in recent memory is the Haiku sent in by Henk Lu.



The owner requested nine slots at the tail & the challenging part of that was figuring out how many slot positions are taken by the clip. IIRC the spacing ended up at 25.7°

[jhanko]

ROFLMAO

I am interested in your Excel spreadsheet - would you email that?

A download link is in the post. Just click on the words "simple spreadsheet".

[mohanjude]

A download link is in the post. Just click on the words "simple spreadsheet".

What I find quite challenging is on the SVM V10r there are the dreaded 4 holes for a key chain. So when indexing you have to accomodate those holes as well. I had a system where I used to space 3 slots between the 90 degree holes on the bottom shoulder but find it cumbersome as it is difficult to estimate the centre of the holes.

1st slot 20 degrees from hole
2nd slot move 25 degrees - 45 degrees
3rd slot move 25 degrees - 70 degrees
20 degree slot to next hole

total 90 degrees.

Anybody have a simple method to accomodate the holes, clip holes ?

[precisionworks]

it is difficult to estimate the centre of the holes.

For the slots to space out exactly the hole center cannot be estimated. Centering doesn't have to be dead on but it does need to be no more than 0.025mm in any direction from exact center. More more than that & the error is easy to detect by people who have 20/20 vision.

The traditional way to find exact hole center is to touch off the inside of the hole with the tip of a dial test indicator. Rotate the spindle 180° & note the reading, adjust the table to split the diff, rotate 180° again, split again, etc. Then repeat by turning the spindle 90° and going back & forth. When done the indicator can be rotated around the entire inside of the hole & will not move more than 0.025mm. An optical centering microscope is a little easier to use & most run no more than about $200 USD. Hemingway Kits in the UK makes a nice one.

You may want to post that question in the Machining Forum & will certainly get more suggestions.

[precisionworks]

Posted a terrible image earlier & it bothered me all afternoon. Deleted that one & these are much more representative:





My wife came out to the shop to let me know that dinner was ready. I sort of think she pops in to see if there are any new tools that I might have forgotten to tell her about. As we walked out the door she said "you left a bright green light on in that room." What could I say

[Silgt]

I think you've just persuaded me to order an anti-roll tail from TnC...not good...not good at all!

[mohanjude]

For the slots to space out exactly the hole center cannot be estimated. Centering doesn't have to be dead on but it does need to be no more than 0.025mm in any direction from exact center. More more than that & the error is easy to detect by people who have 20/20 vision. The traditional way to find exact hole center is to touch off the inside of the hole with the tip of a dial test indicator. Rotate the spindle 180° & note the reading, adjust the table to split the diff, rotate 180° again, split again, etc. Then repeat by turning the spindle 90° and going back & forth. When done the indicator can be rotated around the entire inside of the hole & will not move more than 0.025mm. An optical centering microscope is a little easier to use & most run no more than about $200 USD. Hemingway Kits in the UK makes a nice one. You may want to post that question in the Machining Forum & will certainly get more suggestions.

Thanks for that. I will look at the hemingway kit.

[precisionworks]

Thanks for that. I will look at the hemingway kit.

You're certainly welcome.

... you've just persuaded me to order an anti-roll tail from TnC...not good...not good at all!

LOL

TnC sells the entire light for $398, making it one of the best values available today. Seems like he's often back ordered on these & that's no surprise. Most people look at the outside of a light & focus on fit & finish. The inside of those lights is equally as well done. Smoothly bored, slick threading, very solid construction.

If you don't plan to use a lanyard the tail can be requested without the lanyard hole, leaving room for a fourth trit. The hole is close enough to the surface that even the smaller 1.5mm slot would break through into the hole.

[precisionworks]

Just finished installing three trits in existing slots in a Peter Atwood stainless steel tumbler. First image shows the size of the tumbler relative to the TnC tail:





As any tritaholic will notice there's plenty of room for another vial or two

IMO the finish was just a bit too reflective so the tumbler got a quick (eight hour) stone wash.

[precisionworks]

Just finished milling slots in a C2 for my friend Matt in Brisbane. The light was bored for 18650 & I'd planned to slot it & ship it out ... in April The good news is that it ships in the morning

C2 slotting is always a challenge since the locations at the center of the corner intersections aren't at 90° or 45° to any reference flat. That means rotate the light in one direction, locate the exact corner edge, note degree reading on the indexer, rotate back to the other corner, note second reading, split the difference. Even then the indexer often has to be tweaked half a degree one way or the other.

These slots are for a 2.5x25mm vial and the width of the narrow edges is roughly 2.1mm. The slots overlap the edges by .2mm on each side.



The wide edges are big enough to land a 747 so those are not so hard.



PLEASE NOTE: If possible it is always best to send your trits with your light. Trits have a wide variation in sizing - my skinny 2.5mm vial measure only 2.47mm while the fat vial measures 2.51mm. That sounds like not a lot but I guarantee that a 2.51mm vial will not go into a 2.47mm slot. Some members like slots that barely allow a vial to slip in & I have no issue making the slots whatever size is desired. Just be sure to include the trits so they can be accurately matched to the slots.

[Mattaus]

Woo!

I never had a clue that so much work went into milling a simple set of straight lines, especially when you appear to have edges to guide you. I guess that's what separates us plebs from the masters like you Barry

Looks amazing and I can't wait to get my grubby hands on it. I have some of my own triple drop-ins that need a test host and this will be perfect!

Thanks again,

- Matt

[precisionworks]

Thank you for your kind words Matt

never had a clue that so much work went into milling a simple set of straight lines, especially when you appear to have edges to guide you.

The edges are a mixed blessing. On a round light the trit slots have few visual references & there is less measuring & center finding. Because the C2/C3 have two very narrow edges any location error is glaring. Imagine how the image below would look if the slot were over to one side or the other by 0.1mm.



To get a nice tight slot these were cut with an undersized tool measuring 2.38mm (.0938"). The "middle" or main slot is milled out first. It's measured for width and the required step over is dialed into the mill table - half of the step over goes on either side of the main slot. It would go a little faster using a 2.5mm tool but tools sometimes cut over sized & it's really hard to put metal back into the slot once it's gone.

[precisionworks]

Finally got back to the TnC Ti host this evening & started slotting the head. It's going to look pretty cool with 16 green trits



Hard to tell the factory slots from the new slots unless there's a magnifier handy. The factory slots are very slightly chamfered (or beveled) & the new ones are not:



Detail view of one slot:



After capturing the above image I felt pretty cocky Absolute perfection thought I. So the camera was set up today after finishing the head & a really really close image was taken ... which shows that nothing is perfect if you have enough magnification. Slot is 1.5mm wide by 5mm long (plus the two rounded ends):



Look closely & you'll see a number of horizontal lines, each one representing one milling pass at a depth of cut of 0.1mm (.004"). A total of seventeen passes were taken to reach final depth of 1.7mm.

[precisionworks]

All done & trits installed

[Mattaus]

hmmm....the GITD rings kinda kill the look in my personal opinion. They look out of place and it's exacerbated by the fact the 2 rings are not the same thickness. Trits look even and like they belong - the rings? Not so much.

Each to his own though! I'm sure the new owner will love it.

[dbleznak]

I like your feedback on the rings Matt! I'm so glad Barry didn't use norland!! HaHa. For real, the rings are temporary. Sometimes, too much GITD is visually overwhelming. I think in this case, your right. Now, this stunner needs to marry your drop-in.

And Barry, your work is always pristine !!!

All I can say is - get home safe my beautiful trit Queen!!

[precisionworks]

I like your feedback on the rings Matt!

I saw that last night just before turning off the lights. Happy that you took it in the spirit in which it was intended

A row of trit dots at each end might be more pleasing

[tobrien]

I saw that last night just before turning off the lights. Happy that you took it in the spirit in which it was intended

A row of trit dots at each end might be more pleasing

Hollllly cow

[precisionworks]

Hollllly cow

LOL

Of course I'm not serious. But it looked like a fun thing to do.

[tobrien]

LOL

Of course I'm not serious. But it looked like a fun thing to do.

so that pic isn't real?

[dbleznak]

I LOVE IT!!!

[precisionworks]

I LOVE IT!!!

Somehow that doesn't surprise me

I blacked out the GITD rings & tried to pick a really bright green for the dashed line. Sorry for the confusion, I should have been more clear.

[Mattaus]

I saw that last night just before turning off the lights. Happy that you took it in the spirit in which it was intended

haha yes...i'll never be critical without being constructive! And like I said - each person has their own opinions on what does and doesn't look good. The world would be very boring if everyone liked and hated the same things...

[dbleznak]

How does that song from the 60's go...."free to be you and me"?