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Case Disaster


prospex44

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Hi guys,

Well I had a disaster this afternoon while working on my 5513.

I had a 5513 Cartel watch from Perfect Clones.

I was planning on modding it fully.

I was drilling the lugs out to accept the gen size bars, when I was having real difficulty with one of the lugs in particular.

The drill bit snapped off inside the lug and I feared the worst, but after some banging about I managed to get it out. While there was a small "hole" after this, going all the way the lug, it was way too thin. So I put in a fresh drill bit and re-drilled the hole. The drill was literally red hot and when I took it out, it seems to have fused with the case (lug).

Anyway, I used a dremmel with 1.3mm tungsten bits, I ending up going through about 9 bits, all of which were destroyed while trying to drill this lug. The result is a complete mess and a totally destroyed and useless case.

I am totally gutted to say the least! Just don't understand what I did wrong! I used a little oil as I thought this would stop any sticking, could it be this has heated up too much? Would I have been better using nothing. What drills should I use?

Anyway, I feel like a complete idiot now, and really sick at the money I have now lost with this project.

Here is the nasty result of my butchered case....

f31d2456f2dfce4c1e659bd8c6232dea.jpg

035a2ad222bc1cdf57d222f2bc40cff4.jpg

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So my question is guys, would anyone be able to point me in the direction of a suitable case I could buy? I would like to try and salvage something out of this.

Mine had the 21j 2813 movement, and I have Yuki insert and Athaya crown and tube, etc.

I just need to find a replacement case.

Thanks guys.

Sent from my iPad using Tapatalk

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I drilled mine without difficulty. I used one cobalt drill bit and drill oil. The key is to drill a little at a time and don't force to not heat the bit. Drill a little, stop to cool the bit, drill... And don't hesitate to use a lot of oil.

I know Josh sell case only.

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Thanks, perhaps it was an incorrect drill bit I used, I should have used Cobalt bits!

I'll send Josh an email and see if I can buy a case from him!

Thanks

Sent from my iPhone using Tapatalk

I think it could be salvageable. See if a local engineering firm can spark erode it out for you

Thanks for you answer also, I live in a small town, so no engineering firms local I'm affraid!

What is spark erode?

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36 minutes ago, Bart Cordell said:

I drilled mine without difficulty. I used one cobalt drill bit and drill oil. The key is to drill a little at a time and don't force to not heat the bit. Drill a little, stop to cool the bit, drill... And don't hesitate to use a lot of oil.

I know Josh sell case only.

emoji632.png

This ^

Low speed, fairly firm feed, lots of oil. Use cobalt as mentioned. STOP 3 or 4 times during each hole to let the bit cool down. You did overheat and fuse the metals!

 

B

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I've drilled many cases. Usually non-lug holed cases, which is much more difficult than just enlarging existing 1mm holes.

First of all, are you seriously drilling with a dremel? Are you at least using a dremel press? Or are you hand holding the dremel?

You really should use 1.25mm bits with a proper drill press at as high a speed as possible. Clamping the case with a two axis vice is also recommended. 1.3mm is not gen spec. Cobalt, tungsten, hss... Really doesn't matter much if you keep the bit reasonably cool.

Luckily, cartel cases are relatively cheap. These things happen and I'm sure your next attempt will be significantly better. Good luck.

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Sorry to hear this.

I use my dremel for a lot of stuff but would not try and drill lug holes with it.

May want to try a different set up. I will do some shaping and other work with a dremel but generally will have someone with a good press and clamp do lug holes.

JMB does them for reasonable price.

Good luck.

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Im 100%sure this happens more often than people would admit it..

if you can get the sword out of the stone, I could possibly laser weld you're case and drill it so it looks acceptable to use :)

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If you broke off a carbide bit they are extremely brittle and you should be able to hit the inside with a center punch.  Since you have royally buggered up that particular hole you could go ahead and drill all of them bigger, install solid lug bars, and make a MILSUB...  I would say to soak the lug tip in a strong citric acid solution but I don't know if that will eat tungsten/carbide...

When drilling into existing "divots" you need to drill at the highest speed your equipment can provide or you will likely snap a bit when it breaks through into that "divot."

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JMB is the lug drilling expert, but coming from an engineering background myself I can vouch for using the high speed low feed approach to stainless steel. I would use a drilling and tapping fluid rather than oil as oil tends to heat up. Beginners including me when I was an apprentice tend to put pressure on the drill to force it through. This is pretty much guaranteed to screw up. Let the cutting edge do the work and stop at the first sign of heat build up. Stainless is tough, buy the best drill bits you can get.

As to engineering firms, spark erosion and welding. Well it's only metal and can be repaired, but cost is a factor as a cartel watch is only just over a hundred Bucks. Maybe just take the loss as a learning experience. Worse and more costly mistakes have been made and you have some useful spare parts now.

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Thanks for the responses guys, I just feel like a complete $#%€!! How could I have been so stupid!

I suppose if anything good can come out of this, hopefully it'll save some other poor soul doing this to their case!

I have a dewalt battery drill, do you think I should use that rather than the dremmel next time? Along with some cobalt bits!

I have emailed Josh about possibly buying another case, so just waiting to hear back from him.

Thanks again

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Most stainless watch cases including the reps are 316 stainless which is very prone to work hardening. Chatter on the bit is a problem and was probably pretty bad with the Dremel. People have had great success with hand drills, but ideally a pillar drill and a substantial one is best. If you don't have access to the tools sending the case to JMB is a good option. I don't think he charges much, but you could PM him and ask.

Don't beat yourself up over this. The man who never made a mistake, never made anything.

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14 hours ago, Sogeha said:

Not to rubbish your input, but does the aircraft industry use much stainless? I would have imagined more aluminium and light alloys which I wouldn't be using high speed on

The center portions of cherry locks and high lock mechanical fasteners are steel. The centers need to be drilled out when removing the fastener. We used #30 cobalt split-tips (heavy pressure/fairly low speed). Also, don't kid yourself there is plenty of steel on aircraft...especially nacelles.

 

B

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I'm interested in light aviation, but not knowledgable about the engineering side. I imagined everything would be metal alloys and fancy stuff. Most of the planes I'm really interested use birch ply :-)

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