Reamers and drill bits

[ra_balke]

I have a .358 diameter hole, in gun barrel steel.

I want to ream it to .375.

Please to what diameter must I drill this hole in order to do a finish ream to diameter .375.

[Doc Highwall]

You could also ream it instead of drilling for a smoother finish.

[longbow]

Not sure if this helps or not but here are a couple of links:

http://www.yankeereamer.com/Tech_Info/tech_info.html
http://www.nedians.8m.com/reamer.htm

I make D bits for reaming and they seem to cut quite well even when the hole is much undersize.

What are you making?

Longbow

[ra_balke]

What I am making,, well, I have a Smith&Wesson Model 34 kitgun with 4 in slender bbl.
One of the newer guns w/o a pin bbl.

I love the gun , but I hate the ballance, so I ordered a 3 inch model 36 , caliber 38 , Heavy barrel from Numrich, and I plan to ream it out to .375, then instal a 22 caliber liner, and make for myself a well ballanced heavy barrel 3 in ,, caliber 22 RF revolver.

I have a .358 chucking reamer, and I have reamed out the rifling, it is now smooth bore, but the liner is .375 diameter, so I must ream it to .375 to fit the new tube.

After, I plan to weld the sight up higher in steps, then file it off, then do a re blue to match the Smith Wesson color,,, then... send it to an outfit to be lazer engraves to say 22 on the bbl.

We gun people can be idiots.

[garandsrus]

ra_balke,

I believe that a machinist would normally drill 1/64" smaller and then ream to the final size. This would remove about .016 material with the reamer.

John

[deltaenterprizes]

ra_balke,

I believe that a machinist would normally drill 1/64" smaller and then ream to the final size. This would remove about .016 material with the reamer.

John

I second that.

[BruceB]

"We gun people can be idiots."

If it makes you think better of yourself, your project makes perfect sense to me.

Many years ago, I had a 4" Kit Gun which hated me (the feeling was mutual). In spite of being a very active Bullseye competitor, meaning familiarity with sight picture, trigger pull and all those other pesky details, I could NOT shoot that gun!

I do believe that your project will create another example of "a gun S&W SHOULD have made", and I sure wish I had one like it. The M18 in .22 on the K-frame is very nice, but the J-frame is where the .22 should be....with the heavy barrel. Please post as you work through this endeavor.

[Buckshot]

ra_balke,

I believe that a machinist would normally drill 1/64" smaller and then ream to the final size. This would remove about .016 material with the reamer.

John

............Depends on the size of the reamer naturally and for a .375" reamer it's close. A reamer does need to have something to cut, and in some materials not enough can keep the reamer from doing it's job by not allowing it to 'get a bite'.

According to M.A. Ford cutting tools, a .375" reamer wants:

Steel >35% carbon .012"
<35% carbon .012"
Tool .012"
Hard .010" (no hardness given, but suitable for HSS reamers)

If your liner is .375" you're going to want just a bit of room in there for solder, epoxy, or some type of Loc-Tite type stuff aren't you?

..............Buckshot

[Bret4207]

If your liner is .375" you're going to want just a bit of room in there for solder, epoxy, or some type of Loc-Tite type stuff aren't you?

..............Buckshot

My thoughts exactly. I'm not sure just how much wiggle room you want, but I'd figure .005 or so. FYI- if you're using Loctite/Acrcaglass/Epoxy a rougher finish holds better. That include roughing the outside of the liner.

[Franklin Zeman]

I tried to make a Model #34 shoot a number of years ago. The result was in the grips. With a BIG hand, the grips made a major difference in my target accuracy with that rig. Never did figure out why, just that it was how it reacted to my shooting.

[deltaenterprizes]

Consistent grip is one of shooting fundamentals.
Grip
Stance
Sight alignment
Trigger control
Breath control.

[Pavogrande]

If, you are boring it out for a liner, why bother reaming? just drill it out to size. The roughness and slight oversize will give the solder or epoxy room and "bite" -- my ha-penny

[John Taylor]

I install several liners a week so I better jump in here with some answers for you. First, don't ream any more out of your barrel, turn the liner down to fit the reamed hole you have now. If you are using Loctite don't worry about making the surface rough, it will hold on a very smooth surface. I try for about .002" clearance and use the high strength Loctite. On a short barrel like your pistol I would bore into the barrel on the cylinder end a little so there is a step and machine the liner to fit with a portion to fit the step. I have never had a liner come loose but the step will make sure it does not move. Clean the two parts, I use brake cleaner. Coat both parts and put them together, It works best if you liner is longer than you need then trim to finish, crown and do forcing cone.
I do not use epoxy on liners. I have used solder but it messes up the out side finish from the flux and heat. The flux is designed to clean the metal and will take blue off.

[John Taylor]

Here is a picture of a Colt 45 barrel ready for the liner. The liner has been turned down and has a wall thickness of .035" . OD is .526 and the step is .560

[257 Shooter]

John, That is a beautiful fit. Great work!

[Franklin Zeman]

As I understand it, the best advice was to use the original barrel and either slender it up to fit the larger barrel, or make the hole larger in the new barrel to fit the original .22 barrel as is. Does that make sense?

[Char-Gar]

I am far from an expert machinest, but I have reamed a few gun barrels making stright line bullet seaters out of the chamber and a few inches of barrel. I have had no problems removing .010 of stock with a chucking reamer in the lathe. I suppose you could go a few thou more or less and get good results.

So, I would hunt up a drill that is .005 to .015 smaller than your reamer and have at it.

[John Taylor]

A word of warning. Any drill without a pilot will wander. Might not make much difference on a short barrel but I get barrels in all the time where someone tried to install a liner and just stuck a rod on a standard drill bit. I can't straiten out a hole that wanders all over the place. Even a chucking reamer will not follow the bore. On a short pistol barrel this does not make a big problem. On Rifle barrels the reamer is attached to a tube and oils is pumped through the tube to lube the cutter, keep it cool and remove chips. It is pulled, not pushed.

[honus]

A word of warning. Any drill without a pilot will wander. Might not make much difference on a short barrel but I get barrels in all the time where someone tried to install a liner and just stuck a rod on a standard drill bit. I can't straiten out a hole that wanders all over the place. Even a chucking reamer will not follow the bore. On a short pistol barrel this does not make a big problem. On Rifle barrels the reamer is attached to a tube and oils is pumped through the tube to lube the cutter, keep it cool and remove chips. It is pulled, not pushed.

Listen to the man. I used to install several liners a week and John's right on the mark. Smiths charge more to fix "fixed" guns, than to do it correctly the first time.

[giz189]

John, I am not a machinist by any means, but I like to study the art and skills of people who are. Tell us, how did you get the muzzle end to not show the joint between original barrel and liner. Beautiful work.