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New Mod To My Frankensub


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get that testing started buddy :) these small lugholes are killing me......

I was hesitant to do it myself, but the lug hole mod really IS easy.

Based on Edge and Ziggy's wonderful tutorials (and after some supplemental discussion), I used a 1.3mm Cobalt drill bit (which never jammed or broke), an inexpensive Black & Decker hand drill and some 3-in-1 oil. I wrapped the (unopened) watch in Viva papertowels (to keep the oil from seeping into the case) and held it in my hand. Then, with the other hand, I lined up the drill bit with the first hole and ran it through at moderate speed. I stopped a couple of times on the way through to clear out the metal shavings, re-oil and then continued all the way through. The first hole took about two minutes, if that much. And, as my experience level increased, each subsequent hole took even less time than the previous one. I probably sailed (carefully) through the last hole in less than 30 seconds. Just be sure to keep the drill pointed directly into the hole so you don't "oval" it.

Then I cleaned the small amount of burring around the hole with a Dremel "Stainless Steel" wire brush attachment. This took about a minute for each hole.

Then I used the Dremel white cloth wheel attachment with some green rouge to buff/polish the outside of each lug to return it to its original shine. About five or six minutes for each side of the case. (I had some experience buffing watch cases when I was a kid, so it might take you a bit more time here...but not much more.)

Finally (and this did take a bit of time), I had to grind down the portion of each end piece that fits against the case, because the new (20mm long, 2mm diameter) springbar pins wouldn't quite line up with the lug holes. This took the most time, probably around 15 minutes of trial-and-error grinding and test-fitting until everything snapped together again. In fact, I was quite surprised at how easy this procedure actually is and how well the finished product turned out. The lug holes look absolutely genuine (for a vintage Sub/SD case):

post-3175-1162400571_thumb.jpg

I don't think I spent more than an hour on the entire operation. Cleaning up the green rouge (that covered EVERYTHING in the room) was another story....

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@freddy333...

you kinda missed the whole point here. as yor lugholes indeed look great, we were dicussing how to rebias misplaced lugholes, some cases have the lugholes to far off center, which doesnt leave much clearence for drilling the hole bigger cause it might end up coming right up to the top end of the lug.

so, we're trying to figure out how to solve this issue without destroying a very difficult to find case.

cheers :)

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lionsandtigers,

Oops, I guess I missed that. My apologies.

Other than welding the holes closed and then redrilling (with a drill press) entirely new holes, I can't see how to move or rebias an existing hole. I used to restore cars and this was a fairly common problem.

And I hope you don't mind my asking, but why is this case so revered if the lug holes are off-center? I would think that would immediately preclude it from any kind of serious consideration.

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no problem buddy, andi agree, you would think that it would interfere with the desire for this case, but the case itself, other then the lugholes, is pretty much perfect in every other way.

i wasnt aware that this was such a common thing with the tw classic cases, personally, i probably would have gone for one without the lugholes if i knew...

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well, i can report progress on the drilling project......i bought a drill press and press vice this weekend!!! :D

now i am waiting for the 1.3mm cobalt bits to arrive. :whistling::whistling:

i also bought some diamond tipped bits that have varying tip geometries. my plan is to use one of the long conical ones to grind/make a starter edge on the existing hole to act as a guide for when i use the cobalt bit. this should allow me to bias the hole away from the edge and more towards the inner portion of the lug.

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...and thats my Franken,do you see the difference?

144834-15901.jpg

The differnce that i can't work on it is the crownposition....

But hey,it's a rep ;)

The bezel is a little different. And either your case is thinner making your lugholes look bigger than the gen, or your lughold *are* bigger than the gen. Hard to say which, but I'd bet on the case thickness.

These difference are extremely minor. Your franken is a winner!!

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well, i can report progress on the drilling project......i bought a drill press and press vice this weekend!!! :D

now i am waiting for the 1.3mm cobalt bits to arrive. :whistling::whistling:

i also bought some diamond tipped bits that have varying tip geometries. my plan is to use one of the long conical ones to grind/make a starter edge on the existing hole to act as a guide for when i use the cobalt bit. this should allow me to bias the hole away from the edge and more towards the inner portion of the lug.

Interesting, but I don't think the grinding will help because that effect will be gone as soon as you drill past it. My guess is that the bit is going to jump like crazy, and might break. I just don't think you can get a clean through hole.

I think the best tool is not a drill bit, but a milling machine end mill. Here's one in 1.5mm - http://www.cuttingtoolsource.com/endmills_...ic_ballnose.htm

Here are some more - http://drillcity.stores.yahoo.net/endmills1.html

I'd call a couple of these places and try to find a 1.3mm end mill. Run that at a very slow speed on the press. I think that'll yield better results. I'm just guessing of course, but that's what I'd try.

Good luck!

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no problem buddy, andi agree, you would think that it would interfere with the desire for this case, but the case itself, other then the lugholes, is pretty much perfect in every other way.

i wasnt aware that this was such a common thing with the tw classic cases, personally, i probably would have gone for one without the lugholes if i knew...

Is "tw" Andrew? If so, then it must be a case-specific problem because the lug holes on the DRSD I recently received from him (which is next to be modded after I finish the Newman Daytona) are in the same locations as the vintage 5514 Comex I referred to in my initial response to you.

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@freddy- no, these are older cases that came out of Taiwan 3-4 years ago. they were sold by river, eddie, and a few other dealers.

@chief - thanks for the end mill links. here's my logic regarding my original methodology. the current hole is off-bias and is smaller than the required 1.3mm. if i mill with a diamond tip, the new lower edge that the bit should take, the carbide tip should fit into this new starter hole and then mill/bite to follow the rest of the way through creating the new path/hole. i'm conceptually thinking of viewing the current hole and the new hole as concentric circles from a top-down view....the new hole will be larger than the current hole just the center moves. if i widen the existing hole in the direction the new hole needs to go, then the fixed nature of case lug in the drill press vise and the fixed head lowering slowly (with the cobalt bit shortened to minimize flex) should allow it to follow the new hole and not drift back to follow the path of the current hole. how would a end mill bit work better? is it designed to minimized tip flex? :unsure:

Edited by haveblue
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@chief - thanks for the end mill links. here's my logic regarding my original methodology. the current hole is off-bias and is smaller than the required 1.3mm. if i mill with a diamond tip, the new lower edge that the bit should take, the carbide tip should fit into this new starter hole and then mill/bite to follow the rest of the way through creating the new path/hole. i'm conceptually thinking of viewing the current hole and the new hole as concentric circles from a top-down view....the new hole will be larger than the current hole just the center moves. if i widen the existing hole in the direction the new hole needs to go, then the fixed nature of case lug in the drill press vise and the fixed head lowering slowly (with the cobalt bit shortened to minimize flex) should allow it to follow the new hole and not drift back to follow the path of the current hole. how would a end mill bit work better? is it designed to minimized tip flex? :unsure:

End mills are meant to withstand lateral force and resist bending. They are made for CNC machines. Drill bits are not.

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