$#@%$#!*^@ broken tap

[mahkagari]

I have lost count of the drill bits I have broken on this project. Now I broke a tap off in my trigger plate. :cursing: I swear, I need to cut back on the Wheaties or something, this is getting ridiculous.

 

[Artificer]

What kind of tapping lubricant and/or lubrication are you using when drilling or tapping?

The VERY BEST drilling/machining/tapping fluid I ever ran across and have been using for decades is: Mike-O-Cut 87. I use to be able to get small tubes of it, but lately I have only been able to find it in the 16 oz bottles. However, if you do buy one of those, it would last you for many years.
https://www.fastenal.com/products/details/0316633
Gus

P.S. You may be able to get a smaller quantity from a machinist friend or Industrial Arts teacher.

 

[Col. Batguano]

been there done that. In a forward bolt for a lock plate. I tried everything I could think of to extract the stub of the old tap. Nothing worked.
In that case I just ground it flush to the old location, hogged out the hole to a slightly different location and re-drilled. Then I filled up the hole with epoxy putty so the bolt would naturally seek the correct spot when being fed through it during assembly. That's why I use a brand new tap to finish up the holes on every hole I thread. The old ones are ok to start a hole, but it's the break through part that seems to be the "grabbiest" on drill bits and taps, so that's when I change to the new one.

Hope you have enough metal left over to change the location some. The good news is that buried in the TP, it's not a location that will be easily noticed for a little stub like that.

 

[Artificer]

If nothing else works and I assume the trigger plate is steel, I would use a short pin punch to break chips off the broken piece of tap, until the broken piece can be removed or punched out. Then plug the hole with a threaded piece of mild steel rod, peined into both sides of the trigger plate and cut/filed flush to the surface and begin again with a new drill bit and tap.

Gus

 

[jerrywh]

I am not a big fan of HSS taps. I don't think they are as sharp as the carbon steel taps and they are definitely harder to turn because they are duller. Cutting fluid helps but doesn't make up for the difference. Another thing is this. If you break a carbon steel tap off you can anneal it and drill it out. HSS is very hard to anneal.

 

[Vaino]

For the smaller drills used in making MLers, a higher RPM is needed and a light touch.

For drilling brass, the cutting lip of the drill has to be stoned flat...in other words, get rid of the rake angle. Otherwise, the drill will grab and throw the workpiece or the drill will break.

Broken taps are caused by tilting the tap, not clearing chips often enough and not using lube.....Fred

 

[chawbeef]

Broken taps are caused by tilting the tap, not clearing chips often enough and not using lube.....Fred

x2 on this............Daniel

 

[Black Hand]

Use plenty of lube (I use deer tallow) with taps and clear chips often. Don't force drill-bits when drilling metal and use lube (I've used WD40). Also make certain your bits are sharp...

 

[zimmerstutzen]

I mount the taps in a tap handle and then mount that in the drill press and back off the spring that pulls the chuck back up. I line up the angle triple chack it and then start tapping the hole. When it seems like there may be enough oil, put a few more drops on. Turn in very short fractions of a rotation and reverse it a partial turn every time. I pull the tap all the way out and clean the threads every one or two full rotations depending on how fine the tap. Smaller-more frequent. I have broken some over the years, but usually because I was in a hurry and tried to force it too far without reversing and cleaning. An old sewing machine mechanic once gave me the tiniest needle nose pliers I had ever seen. Those things could reach into the flutes of the broken taps and then with another pliers on those, could back out all but the tiny things under 3/32.

 

[rmatt]

Walton tap extractor or similar http://www.waltontools.com/

 

[LRB]

I do about the same. Whenever possible, I set up in a crossing vise, drill my hole with the proper bit, then change the drill bit for my tap, and do as you said by relieving the handle spring tension giving just enough weight to be a positive pressure on the tap. I don't bother with a tap handle in this procedure.

 

[ZUG]

Make or buy a "tap guide". You can drill a hole the size of the tap body into a 1" square block of metal using a drill press and use it as your tap guide or buy one. Directions for it's use can be found here

 

[Vaino]

In addition to using higher speeds w/ the small drills, I use 1500 RPM w/ a 1/16 drill for all the bbl lugs, RR pipe pins and the trigger pivot pins in all of my builds. If a light touch is used, especially when the drill first contacts the lug, drill breakage should be nil.

The tap drills for the lock plate are drilled out of the stock, the lock plate is then put in its inlet and the holes only "spotted" {1/8" deep} and w/ the lock plate removed, the clearance holes are drilled through. W/ the lock plate clamped in its inlet, the lock plate is tapped from the other side of the stock using the clearance holes as a guide....foolproof.

I basically use the same procedure for the tang bolt. After adjusting the stock/bbl ass'y for the correct angle of the tang bolt, a tap drill picks up the center punch in the tang and the hole is drilled through including the trigger plate. W/ the stock/bbl ass'y at the same angle, the clearance drill is used, but only to the bottom of the trigger plate. The tap is then guided by the clearance hole and taps the TPlate. Again w/ the stock/bbl ass'y unmoved, the ctsk is made for the head of the tang bolt. All done w/ 1 setup.

The 2 holes in a brass Bplate require drills w/ the rake removed from the cutting lips w/ a stone to prevent grabbing. The lower hole is easy to drill and ctsk, but the hole in the Bplate return or tang requires a stable wooden block that's high enough to accommodate the Bplate's shoe length. The hole and ctsk are then done.

The tap drill hole for the White Lightning TH liner has the bbl shimmed somewhere along its length to account for a swamped bbl...if it's a straight bbl, no shim ids needed. The shim enables the hole to be at 90 degrees to the bore. W/ the bbl laying flat on the drill press table, the tap drill picks up the center punch and drills through....a light touch is req'd to not dimple the bore. A shallow ctsk is made and the tap is chucked in the drill press brought down to the hole for alignment, brought back up and the drill press is turned on then off and while the spindle is coasting, the tap engages the hole and stops after a few threads are cut. The tap is unchucked and the completion of the tapping is done manually w/ a tap wrench. I only hold the bbl down, but some might prefer clamping it. I like doing this because it eliminates "tilted" tapped holes.

All the tapping is done w/ lube. The holes in the wood are all drilled w/ an electric hole shooter.

Most of you already know all of the above, but evidently, some don't. Judging from some of the posts......drilling and tapping can be a daunting task if not done properly. As is said..."many ways to skin a....", but the above procedures have helped me to eliminate broken drills and taps..... Sorry for the long winded post.....Fred

 

[Bo T]

I was on a machinist forum some years back and one suggested using serial taps for fine work. Say you are cutting 36 tpi at a certain size. Your first cut would be made using 36 tpi a size down. This will give you shallow, easily cut threads. And it will give an easier, cleaner cut for the final threads. And less change of breaking the tap. Leastways, that is what was indicated.

 

[ohio ramrod]

When I first stated in a machine shop they used a mixture of white lead and kerosene for tapping lube. ( I am telling my age here)Today I prefer STP for a tapping lube. As stated earlier , high carbon taps are easier to remove when broken than HSS.The main thing with tapping a hole is to keep the tap aligned, torque evenly, and "clear" your chips often. :idunno: :idunno: