Cutting in an adjustable comb FYI

[MBTcustom]

Here's a simple tutorial on how to cut in an adjustable comb (cheekpiece) on a rifle, and specifically, and M1A.
This requires some machinery, but those of you that do not have access to a mill and lathe might be able to use some of what I say here to your advantage if you have a mind to do something like this.

First, it is nessisary to plug the tool holes in the stock so that your pillars have something to be glues to. An M1A(M14) has surprisingly little in the way of excess wood.
I measured the holes in my butstock at .815.
Rip two staves of walnut that were about 1" square and 12" long.
Scribe a line corner to corner on both ends, and pop a 60 degree center drill in the middle of the X.
Mount the staves in the lathe between centers and use the friction of the one on the chuck (just a rough point turned in a piece of material. The rougher the better) to drive the stave while you turn it to a usable diameter on the tailstock side.
Once both are done, flip them around and hold them in the chuck now that you have a precision diameter to grip on, and stick the tailstock center in the other end.
Turn the staves to a diameter of .800-.805.
You want a nice easy slip fit. Check them in the stock:
Attachment 109298
Take a pencil and spin the dowels in their holes as you press the tip into the crease. This will tell you where to cut them off at.
Attachment 109299
Label them as TOP and BOTTOM
Attachment 109300
Saw them off and glue in place with Acraglass or tightbond III (anything waterproof will do)
Attachment 109301
Attachment 109302

Next make the pillars. Mine were 1" long and .75 in diameter with a 10-32 hole drilled and tapped through 3/16" from one end. The "lube grooves" are for the bedding compound to ride (I do the same thing to my pillars) and creates a mechanical lock.
Attachment 109303
Attachment 109304
Next, tape off the back of the stock and use a pen or a sharpy to lay out the comb section, and screw a flat piece of wood to the butt of the stock. (this keeps the stock true as it's being cut. If it gets twisty, it will look like a weirdo did it, and you absolutely need a flat unchanging surface to indicate off of)
Attachment 109305
Saw out the profile of the comb
Attachment 109306
Attachment 109307

[MBTcustom]

Now here's the tricky part, and I have a trick to help you. You see all those nasty looking sawcut marks you just put in your stock whilst cutting out the comb? Well if you think now is the time to file those out, you're crazy. Those are identical mirror images on both the top and the bottom of the comb, and you are going to use those as witness marks to align things with.
Look at this picture here:
Attachment 109310
You see the pencil pointing at a very well defined saw mark in the wood? That is an indicator for you. Take your calipers and measure the stock right there, devide by two, lock those calipers, hook one tip on the outside of the cut and use the other to scratch the freshly cut surface right in the middle. Do this from both the right and the left of the stock so that you have an absolutely perfect mark in the ver center of the cut. Do the same on the back part of the cut, both the comb and the stock and scribe a perfect line down the middle of both (if you were waiting for the perfect time to be an anal retentive perfection demanding jerk, now is your moment. Knock yourself out. You just cant be too perfect here because you will be eyeballing everything with these marks and the quality of the finished product depends on it:
Attachment 109313
Attachment 109314
Now fixture up the stock in the mill. What? Your vice has trouble holding a stock rigidly? Your'e a booliteer! Go spend some time in paper patching sections. You will learn that paper doesn't compress very easily. Use paper to shim up your vice. I use card paper and fold a whole sheet till it was about 1" wide and 4" long, one on either side where things get skinny. Works great.
Use picture frame levels (two of them in tandem) to make absolutely sure you are level in both X and Y directions, and again, be as anal as you please.
Now, take your wiggler and get the wiggle out of it. Use it to align your vice so that your perfect pencil mark is parallel to the machine table.
Use it to find your edges in the Y direction and divide by two to put you perfectly in the middle of the stock, then bounce between the two marks in the X direciton to put you perfectly between them. All you are looking for is a repeatable 3D point you can find on both pieces of wood.
Attachment 109316
Now use a 3/4" centercutting endmill to sink two holes exactly 1" deep equally spaced from your center point you zeroed on the DRO, or whatever you have.
Yes, the bedding compound is going to keep them from seating all the way down. That's a good thing. That allows you to dress the pillars down flat with the wood so that it looks like you gave a darn about how things look when they are done.
Attachment 109317
Hmmmm. Snazzy lookin.
Attachment 109318
Do the same thing to your comb piece as far as super anal retentive setup blah blah blah, and pop two 3/8" holes in there 3/4" deep. Your guide rods will fit into these.

Now, chuck the remainder of your 3/4" stock in the vice, and pop a .228 hole through it, .812 from the end. Without moving it, or even turning the machine off, plug your stock onto that stud, eyeball it level and pop a hole cross ways through the stock. These are the holes for your lock screws.
Sorry, no picture of that operation. If any of you think you could do better, then you're sure welcome to try.
This is what you are after:
Attachment 109319
Now, just do a dry build and make sure everything looks and works right.
Attachment 109320
Now glue the pillars in place by using a small setscrew to hold a piece of your 3/8" rod. Sklorch the bushings into the stock with lots of bedding compound, and let it dry, and do the same to the guide rods in the comb. (Use the 3/8" rod to twist the bushings into alignment, and remove your little setscrew through the access holes.)
Use a drill to clean the compound out of the bushings and to push a clearance hole down into the stock for the rod to ride in (the bushings aren't long enough to support 1 1/2" of guide rod you know). Finally, run a tap through the access holes to clear the threads.

Once everything is set up, draw file and sand the rough sawn parts to a smooth finish and dob on some truoil.
Attachment 109321
Once that is done, put it together and make sure everything still works well. The guide rods may stick, but if they do, bust out the blue Dykem, find the problem and make it go away with a file.

Attachment 109322

[MBTcustom]

Voila. God bless you all.
Attachment 109323

Attachment 109324

[nhrifle]

Nicely done! A customer brought me his rifle this weekend and asked me to put a cartridge trap in the buttstock to hold an extra 5 rounds. I'm thinking of doing something similar to your adjustable comb to accomplish what he wants. I have not yet started any cutting on his stock yet as I want to be darn sure of what the plan is before I start -- it's an extremely nice Weatherby Mark 5 with presentation walnut.

[Dryball]

Beautiful work...I never woulda thought of putting an adjustable cheek piece on an M1A. NH, I like your customer's idea too.

[EMC45]

Nice job! Sklorch? Must be a gunsmithing term.....

[Larry Gibson]

Very nicely done!

Larry Gibson

[MBTcustom]

Nice job! Sklorch? Must be a gunsmithing term.....

Its the poopy diaper in progress sound that the bushings make when you push them in their holes. LOL!

[1845greyhounds]

I know just the rifle I'll do this to. Thanks for documenting and sharing!

[MrWolf]

Aye, very nicely done a great explanation.

[MBTcustom]

Glad to help fellers. Hope it does somebody some good. It's not the fanciest system in the world, but it's about the simplest, and looks pretty good too.

[Larry_65]

Where are the attachments. I would greatly like to see these. Thanks, Larry_65

[Red Elk]

Agree with Larry 65, I cannot access the attachments either. Is there something that I can do to access them besides click on the link?
re

[M-Tecs]

This is from 2014. The attachments no longer appear to be active.