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Trying to prevent a F$@# up

acemedic

Plastic
Joined
May 14, 2020
So a buddy has given me his glock slide to cut an RMR mount.

Tried it multiple times with a blank to test it out. Test worked really well. I didn't realize the slide was 7075 aluminum.

I now have a vanadium HSS tap that's broken off inside the slide. I don't believe it's very deep (I don't think the hole drilled all the way. I think the bit slipped up into the holder), so my goal is to try and drill out the metal that's stuck inside the hole. (open to suggestion if there's a better way)

I've got Fusion 360, using a Tormach 1100M and can drill on the same position. The drill bit is HSS/black oxide.

Suggestions? Thanks in advance for the help!
 
So a buddy has given me his glock slide to cut an RMR mount.

Tried it multiple times with a blank to test it out. Test worked really well. I didn't realize the slide was 7075 aluminum.

I now have a vanadium HSS tap that's broken off inside the slide. I don't believe it's very deep (I don't think the hole drilled all the way. I think the bit slipped up into the holder), so my goal is to try and drill out the metal that's stuck inside the hole. (open to suggestion if there's a better way)

I've got Fusion 360, using a Tormach 1100M and can drill on the same position. The drill bit is HSS/black oxide.

Suggestions? Thanks in advance for the help!

Topic titles need to inform what your topic is actually about
 
Best way I've found is to helix bore the tap with a small carbide endmill. I've saves some expensive parts that way.

Also, for one-off or small batch high value parts, I much prefer threadmilling over tapping. You can size it in just the way you want, and if the threadmill breaks (which I've only seen once) you can blow it out and try again with a fresh one.
 
1st, I agree with digger doug on the topic.
Anyway, get a carbide endmill big enough to just take the "core" of the tap out.
I set my Fadal to feed at like F0.5 at 1000rpm, go slow.
Then you can pick the pc's out of the threads.
 
You're gonna want to get a carbide endmill (several) and spiral down into that tap in a circle smaller than the minor diameter of the tap. You want to feed down about .0005" at a time, and you want to stop frequently to blow the dust that it's going to create out of the cut area. You're going to ruin at least one endmill. Dem's the breaks. They're cheaper than a new slide.
 
You're gonna want to get a carbide endmill (several) and spiral down into that tap in a circle smaller than the minor diameter of the tap. You want to feed down about .0005" at a time, and you want to stop frequently to blow the dust that it's going to create out of the cut area. You're going to ruin at least one endmill. Dem's the breaks. They're cheaper than a new slide.

I always save beat up carbide endmills for situations like this, I don't like using new tooling knowing it is going to be a sacrifice.
 
+1 for using a ball end mill. They don't have the sharp corners that a flat cutter does to break off instantly when they hit that first bit of fractured HSS. Radius tip endmills work good too.

I usually mill a helix at the same size as my tap drill and use as large of cutter as possible without it having too tight of a helix rotation. Small steps, lots of coolant flow and no fear when you hear things starting to "grind" a little.

Good luck. Sometimes getting taps out can suck.
 
So a buddy has given me his glock slide to cut an RMR mount.

Doing a buddy's slide is the start of the problem. (every time it is a freebie or a buddy hook up, Murphy will bite you in the arse!)
LOL, I have a Gen4 G23 slide that I accidentally 'fish-mouthed' and had to buy his gun. It was his DUTY WEAPON no less.:crazy:
(Slides weren't available aftermarket, at the time.)

I would send it out to a hole popper edm. (tap disintegrator) It would be $125-150, but it should be easy and clean.

You could do it yourself with a carbide endmill, but a risk if the endmill breaks. It could totally trash the hole.

Maybe burn it out with a carbide mill, and helicoil the damaged hole?

My $.02

Doug
 
I always save beat up carbide endmills for situations like this, I don't like using new tooling knowing it is going to be a sacrifice.

Yeah, I have a drawer full of "good enough" endmills in various sizes..... Something tells me this might not be the case in this situation...
 
Listen to teach me he’s telling you like it is. It won’t be a problem. I do slides all the time. I threadmill them. Some of them are real hard like a colt 45 stainless.
Don


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I watched hgr for a nice tap disintegrator paid i think 500.00 came with the power downfeed coolant pump and after some tinkering it has saved my ass more than once. Plus once word gets out you have extra work if you want it. ( high priced of course)


When I find it I don’t need it
When I need it I can’t find it!
 
Get some cheap carbide burrs and use them to flatten the broken tap. If it's still intact the use a carbide end mill.
 
This is the reason I use thread mills on slides….

That being said, I’ve busted off taps in much more expensive chunks of metal… a $20k injection mold rings a bell.

I’ve had success getting a appropriate sized nut and welding it on to the broken tap.

Helical boring usually messes up the threads, but I’ll occasionally do it.

Hole popping (EDM) always works. $60 and a 12 pack seems to be the buddy rate.

Last resort it to bore it out substantially bigger, and press in a chunk of 7075. Machine it back flush and retap.


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Listen to teach me he’s telling you like it is. It won’t be a problem. I do slides all the time. I threadmill them. Some of them are real hard like a colt 45 stainless.
Don


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Ever machine a Chicom Norinko 45?
That was some hard steel. Truth be told, Norinko used to import a nice enough base to make a really high functioning weapon.

I agree with thread milling. Tapping Glock slides broke me of that habit.
 
67c2b44fda83755e3a1112ff59e49e50.jpg

I do quite a few like this
Don


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Hardware store masonry bit? With a green wheel. Grind to cut in reverse and saw off the shank so it has plenty of stiffness. Very surprised the first time I tried one.
 








 
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