Filling and retapping 00-90 holes?

[mike_lawyer]

I have a 00-90 hole in metal that has gotten worn down or stripped.  What is the best way to fill and retap it?  I was thinking of filling it with JB Weld, letting it fully set, then redrilling and tapping.  Anyone know of a better way?

[BCR 570]

I have done this procedure with styrene, where I have enlarged the hole, filled it with styrene rod, and re-drilled once dry.  I would not know hte best solution for re-drilling a hole tapped in metal.

Tim

[Chris333]

I've read you can set something like a small steel ball bearing in the hole and tap it with a hammer to close the hole up, but I never tried it and don't know how well it works.

[peteski]

Yes, drilling a larger hole, filling it with some material, then drilling and tapping sounds  like doable solution.  But drilling oversize hole is important, as JB weld only replacing the stripped threads doesn't seem like a good solution. Would not  be very strong.  Also remember that while JB weld is pretty hard, is is nowhere as durable as metal.  If the threads get lots of repeated use, it will strip again.  No latter what material is used as a plug, it it should be oversize.

If the material is brass, maybe drill a larger hole and solder a piece of brass rod?

[mike_lawyer]

Yes, drilling a larger hole, filling it with some material, then drilling and tapping sounds  like doable solution.  But drilling oversize hole is important, as JB weld only replacing the stripped threads doesn't seem like a good solution. Would not  be very strong.  Also remember that while JB weld is pretty hard, is is nowhere as durable as metal.  If the threads get lots of repeated use, it will strip again.  No latter what material is used as a plug, it it should be oversize.

If the material is brass, maybe drill a larger hole and solder a piece of brass rod?

What size bit would you recommend to drill the oversized hole?

[peteski]

What size bit would you recommend to drill the oversized hole?

That is a good question.  I have never tried this method - I was just thinking about how I would approach the problem.  My thought is that  if JB Weld was used, I would make the hole at least 0.030-0.040" larger diameter than the clearance drill size.  If a metal plug was soldered in, maybe less than that.

So if the clearance drill is #55, (0.052"), I would use #45 (0.082") or #42 (0.093").  This is just an idea - like I said, I have never done that.

We  have several members with machinign experience here - maybe they'll chime in.  @Steveruger45 @Lemosteam  @narrowminded  ?

[mrhedley]

For larger patches I've used sintered metal, but this is probably too small to for that to be effective.  I would think that a patch this small would just flake off upon trying to drill it. 

[Chris333]

Could you change it to a 00-80 screw?

[mike_lawyer]

Unfortunately, I have to stick with a 00-90 screw due to space limitations.

[mmagliaro]

What Chris is describing, hammering a ball bearing on the hole to somewhat close it up, or "peening", probably won't work because I am betting you need to really close this thing up and get good threads all the way inside the hole, and I'll further bet, being 00-90, that there isn't a good way to whack away at it. What about going metric? Instead of going all the way to an 0-80, woudl something like an M1.4 or M1.6 work? Those are about .005" and .010" larger than 00-90, but still smaller than an 0-80. So you might be able to just retap the hole for one of those. Of course, you need metric taps and screws, but eBay will be your friend there.

[Steveruger45]

A lot depends on how thick a metal material you are trying to repair here, Access to front and back and  how much space you have behind the material.
Depending on your situation I would offer the following for consideration.
1. If you can get away with just increasing the screw size being used then just redrill and retap to next suitable size.  I’ve done this many times just by using a metric or BA machine screw instead of the standard one that was just a tad bigger.
2. If you have to use the 00-90  and you have space and access to the rear side then glue a piece of suitably thick brass over he back of the hole and redrill and retap to 00-90.
3. If that wont work and I really had to repair that hole then I would drill out to a tad under he OD of a 1/8” nominal brass rod and press that in.  You would only need a couple to five thousandths interference fit.  Then redrill and retap to 00-90.

Hope this helps

[Steveruger45]

There is also a 00-90 oversized screw thread that might work for you too.
A standard 00-90 thread is 0.050” diameter.
00-90 Oversized Thread: this is the larger 00-90 thread with .052" or 1.27mm major with 90 threads per inch typically used in Jewelry and Eyewear

Attached are some useful size charts to help make a repair decision.
If it were me I would go for redrilling and tapping to the smallest next size up I could get away with even if that had to be metric or BA as it is a lot easier and keeps the original center.

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[Boilerman]

Mike,

Use a 3/32 in. drill held in a Pin-vise and drill 1/2 way from each side, this will give you a chamfer on each side and you will only be drilling and tapping in the epoxy.

[Steveruger45]

Here is the BA thread sizes.
A 12 BA machine screw might just screw right in and hold well without any drilling or retapping the stripped thread at all.

https://britishfasteners.com/threads/

[woodone]

The OP, did not say what kind of metal this is (or I missed that) Brass, I would solder the hole closed and drill and tap.
We don't know what we are holding together either? so soldering may not work if there is a lot of stress on the fastener.
But with a 00-90 screw I don't think we are talking about a lot of stress. Is this screw taken off/on a lot? how about soldering a 00-90 nut behind.
You could J-B weld the nut in place too. 
Need a bit more details, or maybe a photo ?