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 .560http://i95.photobucket.com/albums/l132/johnptaylor/Coltliner.jpg
http://i95.photobucket.com/albums/l132/johnptaylor/Coltliner2.jpg

http://i95.photobucket.com/albums/l132/johnptaylor/Coltliner3.jpg

[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.

[John Taylor]

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.

That's been sort of a trade secret but I will spill it here. I peen the muzzle before I put the liner in. This make the reamed hole a little smaller and gives a metal to metal fit when the liner is driven through. Then the barrel is filed or crowned as normal. The hammer used is 4-8 ounce and has a slight curve to the face. Only peen around the hole, you don't want to flare the barrel out. It takes a little practice to get it even.

[JIMinPHX]

In my experience, a 3/8" reamer likes to see anywhere from .003- .010" of material that needs to be taken off. Many times a drill bit will make a hole that is slightly larger than the diameter of the bit itself. The amount of the overage varies with your drilling technique. The amount that your drill bit varies from hole center will vary with drill bit type, point geometry, hole preparation & fixtureing. A letter U bit is .368" it is what I would use as a pilot for a 3/8" reamer. I would drill the hole with a T bit first, then a U bit to help keep the U bit from drilling too far oversize. I would either center the bits with drill bushings or use screw machine bits in a milling machine or at least chamfer the original hole to help keep things centered. I would use drill bits with 118 degree points, NOT 135 degree points to prevent drill point wandering. Use plenty of oil when cutting. Run your reamer SLOW.

No comments on the gunsmithing side of this. I'm just talking about general machining practices & how to get a good quality hole in a piece of steel.

[giz189]

That's been sort of a trade secret but I will spill it here. I peen the muzzle before I put the liner in. This make the reamed hole a little smaller and gives a metal to metal fit when the liner is driven through. Then the barrel is filed or crowned as normal. The hammer used is 4-8 ounce and has a slight curve to the face. Only peen around the hole, you don't want to flare the barrel out. It takes a little practice to get it even. It certainly works out nicely. Thanks for the info.

[John Taylor]

In my experience, a 3/8" reamer likes to see anywhere from .003- .010" of material that needs to be taken off. Many times a drill bit will make a hole that is slightly larger than the diameter of the bit itself. The amount of the overage varies with your drilling technique. The amount that your drill bit varies from hole center will vary with drill bit type, point geometry, hole preparation & fixtureing. A letter U bit is .368" it is what I would use as a pilot for a 3/8" reamer. I would drill the hole with a T bit first, then a U bit to help keep the U bit from drilling too far oversize. I would either center the bits with drill bushings or use screw machine bits in a milling machine or at least chamfer the original hole to help keep things centered. I would use drill bits with 118 degree points, NOT 135 degree points to prevent drill point wandering. Use plenty of oil when cutting. Run your reamer SLOW.

No comments on the gunsmithing side of this. I'm just talking about general machining practices & how to get a good quality hole in a piece of steel.

I think you missed this in an earlier post " Any drill without a pilot will wander" . I tried boring barrels out a lot of different ways and learned from experience. You might get by with it on a short pistol barrel but a rifle barrel will end up with a slow spiral the full length as the drill takes a little to much out of one side then tries to go back . You end up with some weird looking rifling with a slow twist then try to get your liner in, it can't make the bends to go full length.

[JIMinPHX]

The part that I missed was the part about this being a rifle barrel.

I have managed to get 1/2" holes pretty close to two feet deep in steel & keep them straight when I was making heater cartridge passages in forming dies for plastic molding machines. I did that on a regular old Bridgeport, just by sticking with good machining practices. There were 5 such holes per part & if one was off by more than about .018", then the part was scrap. I didn't scrap very many of them.

For drilling Reeeeaaaalllyyyy deep holes, there is a piece of equipment that is called a gun drill. It's a forced oil contraption, somewhat like what you already described. They have really strange cutter tip geometry. Personally, I am surprised that they work as well as they do, but they do work well.

All that aside, I've never put a sleeve in a barrel myself. Like I said before, I was only commenting on methods of getting a good hole in a piece of steel. I was not trying to comment on the gunsmithing end of things.

I do have an old Star Super that I would like to sleeve, but I haven't figured out how I want to do it yet. There isn't all that much meat to play around with. I'm still considering if it would be better to do a sleeve, remount a new barrel to the chamber & lug, or just cut a whole new barrel from a blank. I'm still hoping to find a new barrel that I can buy. I used to hear people telling me that there was a guy advertising barrels for them in the back of the Shotgun News, but I was never able to find that ad. If anyone has information or suggestions on that, I'm all ears.

[John Taylor]

deep hole drilling is a bit different than boring out an old rifle barrel that already has a hole. Like you said , the gun barrel drills are a bit different and most have a carbide tip mounted on a tube for pressure fed oil and a groove down one side for the chips. Even they will wander a bit, I get new barrels in all the time where one end is off center.
The problem with boring out an existing hole is a little different than making a hole from scratch, especially when old, well use metal is involved. Some of the nickel steel barrels can be a real chore. And if the barrel has ever been in a fire and some fireman squirted water on it when it was hot, then the fun begins. Most of the time I get barrels with rusted bores which will mess up a drill bit very fast. For some reason rust makes it like drilling through sand embedded in the metal.

[JIMinPHX]

deep hole drilling is a bit different than boring out an old rifle barrel that already has a hole.

Agreed, which is why I tried to qualify my statements a little.



Some of the nickel steel barrels can be a real chore.

Agreed, nickel's alloys tend to be tough & generate a lot of heat when you try to cut them. They are very hard on the cutting tools. A lot of people go to cobalt tools when trying to cut those alloys because cobalt has better heat tolerance than regular high speed steel. Unfortunately, cobalt is a little softer, & the toughness of the alloy rears it's ugly head there. I usually try to use regular high speed tooling with a sharp edge, fairly positive cutting edge relief angle, slow spindle speeds, moderate feed rates & a LOT of coolant when cutting that stuff. Again, I am talking about general machining practices here. I'm not claiming to be a gunsmith.



Most of the time I get barrels with rusted bores which will mess up a drill bit very fast. For some reason rust makes it like drilling through sand embedded in the metal.

Rust is much harder than steel. Sand is a good analogy. I would think that it would be a good idea to clean up a rusty old bore with one of those electronic cleaning gizmos, that uses electrolysis, before having at it with a cutting tool. A weak acid solution may be another option to get the rust out. These are just ideas off the top of my head. I haven't drilled any rusty barrels myself. Although that Star barrel that I want to fix up is pretty horribly rusted inside, so I may get a taste of it in the coming months.