Drill and tapping practice material

What kind of receiver? You can easily get a piece of mild steel flat stock at Home Depot or wherever, probably in a thickness pretty close to your gun's receiver. Guns aren't made of mild steel (rather, some hardenable alloy) but it will certainly be close enough for your needs.

Or, aluminum is also available, though not in so many thicknesses at your local hardware store.

If you have a steel sales joint near you, get some 4140 pre-heat treat. This is the 'Chrome-Molly' steel everybody uses. It's what 90% of guns are made of...It's about twice as hard as cold rolled steel, but not especially difficult to drill or tap. About 36-38 Rc.

Try McMaster-Carr for steel flats.

The one thing that can be a PITA is the surface hardening from heat treatment on actions.

Short of treating some flats to about what you measured on a particular action there is not much else you can do.

Look for rusted out junk actions at gun shows, ad use harder drills than you think you need until you are sure about the steel.

Wicks aircraft sells chromemoly tube by the foot I would bet you can get a diameter and wall thickness close to your project from them.

Just get some 1/8" & 1/4" cold rolled steel flat at the hardware store.

You can break off small taps in it as well as anything else!

rc

I don't break taps in cold rolled steel because I use cheap carbon steel taps for that.

I only break carbide taps at $35 apiece in super hard receivers.

Jim

P.S. Don't forget the cutting (tapping) oil.

JK

As for tap lube, I use a mix of equal portions Kendal GT-1 30wt. mixed with Dura Lube. I put that stuff on EVERYTHING from the ways, gears and leadscrews on my lathe and surface grinder, to lubing my guns.

What if you used some steel water pipe?

If that was an absolutely bad choice, please tell me, I want to try drill/tapping some things too, before I do it to my already bubba'd Mauser.

It's a whole bunch easier to get the first couple done on something that's flat. Getting a hole centered on a rounded surface can drive you nuts if you don't.
Also, just something to keep in mind - gunsmiths don't freehand anything. Drilling and tapping is done with a jig, to ensure that the hole is centered on a rounded (or any other) surface. These jigs aren't cheap. The really hard part is getting the feel for when you're getting close to the force required to break your tap, especially in small stuff like a 6-48. The more you've used one tap, the easier it gets to break it as it starts to get dull.
As was already mentioned, don't forget the cutting oil!

My reccomendation to you, is don't worry about the material, so much as the method.

Free-hand drilling and tapping sucks, period. Use a drill press and drill press vise if you can. This will keep your drill/tap straight and square to the workpiece, as well as keep the workpiece steady. For tapping, especially with smaller taps, unplug the drill press, mount the tap in the chuck, and turn the chuck by hand. Don't stress too much about what kind of steel, drill, tap, or lube to use. If you can get it at the hardware store it will be ok. For lube, old motor oil should be fine, honestly. (If it's a pretty gun, you might want to use new motor oil. )

Check around your nearby community colleges to see ic there are any beginner's machine tool classes. Regardless of the age/occupation, you should enjoy the class.

And for the record, yes I am a machinist by trade, so that's my two cents...

[Duplicate post deleted...]

Whoa, there. We are talking a lot about how to drill holes, but what about where to drill them? If the OP is thinking of drilling and tapping a rifle receiver for a scope mount, he best think about getting a jig or learning to set up a milling machine to drill.* Without a jig, drilling holes in a receiver is likely to result in something that looks like a drunken pegleg sailor's tracks in the snow.

*Many machinists swear by using the miller; but it can still be tricky to get the center line and hole spacing right, something a jig does automatically.

Jim

Jim K said:

*Many machinists swear by using the miller; but it can still be tricky to get the center line and hole spacing right, something a jig does automatically.

Click to expand...

I can't speak to jigs specific to firearms, but my experience using them in woodworking and in the machine shop, means that they're seldom a good choice. In fact, on a milling machine, finding the center-line and establishing your hole spacing is pretty easy. Either by using a Digital Read-Out, or even just using you hand-dials. And even on a milling machine, a tape measure, ruler, or 'scale' as we call it in the business, is still your friend. If you have to, put a marker in the drill chuck and "spot" all your holes before drilling. Check your "spots" with a scale, calipers, scope-mounts, whatever before drilling. And learning the skills to do this, as well as find the center-line, and completely indicate your machine and vise straight is all easily learned in a beginner's machine tool class. But we may be getting away from the topic here a bit...

I have used a Bridgeport for many driil and tap jobs on receivers and the process really makes the job easier.
For the Neophite however, some hints are to use a Tap Wrench,ESPECIALLY with the smaller taps,keep the tap STRAIGHT( center hole in wrench helps)and use pleanty of cutting oil. Back off the tap about every turn or two to break the chip,blow hole out with air before "bottom" tapping.
Getting the "feel" is a GREAT help.

Note Bobsmiths picture in this thread.

http://www.thehighroad.org/showpost.php?p=7993019&postcount=68


Any standard T-handle tap wrench can be used with a pointed rod, or center punch chucked in the drill press to hold the tap handle square with the hole you just drilled.
They come center-drilled on the back for just such use.

(As long as you don't allow the hole to move once you drill it.)
Clamp everything down on the table, twice.


http://www.google.com/products/cata...KSNMT6f4AYfaiQKKx6ShDw&sqi=2&ved=0CGQQ8wIwAA#

rc

Clamp your work, then check it and re-clamp. No movement allowed. Plenty of cutting fluid. Verify your hole center before drill/tap. Small gun drills/taps are inexpensive. Consider the taps to be one time use as they break easily when dull. And they do dull quickly. No power on the drill press or mill. Turn by hand only. Watch out for side load on the drill/tap. Develop a feel and watch the tap as you turn it. You will see it flex. It will reinforce just how fragile they are.

"I got a tap wrench that I can chuck."

sing a center is better since it allows float.

Center in drill chuck. use drill press feed to help with down force, rotate t-wrench by hand.

The chuck is stationay and you can rotate the tap handle easily by hand with it rotateing on the pointed center in the stationary chuck..

A tap handle chucked in the drill would require you to turn the whole drill press, motor & all. Thus, no feel and a complete lack of control.

B-Square or someone did make a tap handle that chucked, but I think the T-handle and tap were fee to rotate on the spindel in the chuck.

rc

I knew the milling machine folks would speak out. Fine, but remember that scope bases have fixed holes so you can't just drill holes any old place even if you do get the center line OK. With a good drill press and a good jig, I think it is possible to do just as good a job as with a milling machine and, in my experience, with less time and trouble.

Hobbyists and machinists working on salary sometimes forget that professional gunsmiths don't like to spend any more time on a job than they have to. The quicker and easier any job gets done, the sooner they can turn to the next one. It is all a matter of money.

Jim

I buy steel at a surplus yard [Pacific Iron and Metal in Seattle is cheap] and I buy steel at Speedy Metals on line [expensive].

For the ATI mount for the Mosin Nagant, I wanted to calculated how much torque to apply to the 10-32 screws.

The Mosin Nagant receiver is thin, ~ .1"
The minor diameter of the 10-32 screw is .156".
The screw will break if the thread engagement is 1 to 1.2 times the minor diameter [with high grade screws].
These female threads are thinner than that, so the female threads will strip out.

The max torque for lubed [with oil or grease] 10-32 screws is usually ~ 50 inch pounds.
In 1010 soft steel .1" thick, I found that the drilled and tapped holes stripped out at ~28 inch pounds.

So I was practicing drilling and tapping is some cheap scrap 1010 steel that was the same thickness as the rifle receiver.