Grinding reamers

[bearcove]

How and with what?

Have 2 lathes and a drill/mill. not for profit understand concept never applied

[JSnover]

For chamber reamers you'd want a tool grinder. If you're grinding straight reamers you might get it done on a lathe with a tool post grinder.

[bearcove]

These would be tapered.

[KCSO]

You need a surface grinder and a reamer indexer both way more than buying a reamer. Got my grinder used for about $450

[dverna]

I recall decades ago seeing a series of articles on this. I believe the guy turned tool steel on a lathe to produce the shape of the reamer. He then used a milling attachment to mill off about 50% off the blank. Hardened it and sharpened it. IIRC, he used drills to take out the bulk of material and used the reamer to finish the job

It was not meant to be a production reamer but adaquate to produce a chamber and/or die.

Don Verna

[John Taylor]

I recall decades ago seeing a series of articles on this. I believe the guy turned tool steel on a lathe to produce the shape of the reamer. He then used a milling attachment to mill off about 50% off the blank. Hardened it and sharpened it. IIRC, he used drills to take out the bulk of material and used the reamer to finish the job

It was not meant to be a production reamer but adaquate to produce a chamber and/or die.

Don Verna

This is called a "D" reamer.

[bob208]

it can be done in a lathe with a tool post grinder. harry pope did it that way. but how hard do you want to work? I would try it with my surface grinder and grind all.

[country gent]

Alot depends on the reamer and use of it. set in a tail stock and ran straight in ad out dias ad finish become way more important. A d reamer or form reamer can be set up in a boring bar hlder and the crossfeed used to set dia. Its more a form cutter than a reamer. A little basic lathe set up can be made similar to a case trimmer with stone guides to hand hone sharpen the reamers edges. A couple points for a wilson trimmer and hardened rails or rollers adjustable for hieght and to control cutting angle would work nicely. We made a set up similar at work to make undersized reamers when needed. A few passes with a fine stone on each cutting edge took the reamer down .0003-.0005 in dia so dowels were a press fit in one half of the assembly. If the reamer is being resharpened then it can be kept to size if its tapered if not it will get smaller as you sharpen in.

[Moleman-]

Chamber reamers can be made without a grinder bit it will involve some polishing and more elbow grease. Basically make a drawing of what you want to make. I use O1 and usually turn it .0015"-.002" oversize. Then polish down to .0005" over size starting with a diamond hone on a stick then abrasive tape. My floating reamer holder has a 7/16" hole so I usually turn the tail end to that size then put 4 flats on it so it can also be used with a 3/8" wrench. To cut the flutes take into account the reamer taper when you square it up. I use a standard vertical mill and hold the reamer blank with either a 5C block, indexer or I've even used a modified 6 sided plumb bob in a pinch. You should also support both ends of the reamer. I have a little tailstock for the indexer and made one for the plumb bob and 5c block. Cut down to centerline and feed in whatever will get you close to about .080".095" wide flutes. Then make a final pass .005"-.007" deeper below centerline (so it will cut) and in another .002"-.003" if you want it to look a little cleaner. Then heat to cherry red while spinning on slow speed in a drill press with a long extension on it so heat doesn't get to the chuck. Keep it spinning as you raise a jug of oil up to quench it. I run the reamer in the oil until it is cool enough to handle. Back in the lathe between centers and using a boring bar as a guide for a diamond hone on a stick (parallel with the reamer) sharpen the flats made by the bottom of the end mill. If you have any burrs that didn't take care of, slowly start at the heel of the flute and work the black from heat treating away up to the cutting tip. It's very easy to rotate the reamer too far and take material off of the cutting edge and dull it or change the diameter. That should take care of any burrs left from milling. Here's a few I've made. The wooden cased one is a rimless 357Max with pilots for .357 and .350/.358 barrels, the solid pilot one is a 44x1.8" that my 91 mauser and ar10 is chambered in, and the last one with the bullet isn't done yet and is a 44x1.8 with a floating pilot because I got a few SS blanks that were .002" tighter. In the pic it hasn't been used yet as there is still some black left from the initial polish which was gone once it chambered it's first blank. If you're making something that cuts a case mouth shoulder you should slightly relieve some of the heel area of the case mout shoulder like a drill bit if that makes sense so you're not trying to push 6 .080" flats into the barrel and expect it to cut nice.

[1989toddm]

This thread isn't helping me any! I don't have a lathe or mill but I'm highly tempted to make a 45-90 D-bit reamer to deepen my 45-70 H&R barrel. Probably have to use a drill press. Or a drill clamped to my bench. I'm thinking to use a 1/2" bolt, there is only a minute amount of metal to remove.


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[Mica_Hiebert]

probably be better off renting a reamer

[leftiye]

This thread isn't helping me any! I don't have a lathe or mill but I'm highly tempted to make a 45-90 D-bit reamer to deepen my 45-70 H&R barrel. Probably have to use a drill press. Or a drill clamped to my bench. I'm thinking to use a 1/2" bolt, there is only a minute amount of metal to remove.

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I'd just get a .45 caliber throating reamer. You don't want to cut the chamber itself bigger, it won't help (seriously).

[endwrench]

Well, this thread is definitely helping me! Very cool stuff moleman. I've been plotting out a similar strategy building a reamer for a one-off project like yours. Your explanations are excellent and answer a few questions I had. If you don't mind, I may try to pick your mind later when I commence with my project.

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[1989toddm]

I'd just get a .45 caliber throating reamer. You don't want to cut the chamber itself bigger, it won't help (seriously).

P.m. sent. I don't want to hijack the thread.

[bearcove]

I did the throat on a 45-70 Encore barrel with a throating reamer took about as long as it took me to type this.
Bought it used and resold after done. cost shipping.

I would buy reamers but the stuff I want to do is all wildcat. As far as time to do work that is not a problem. This is a hobby, doing it is the point, cost is a factor as far as buying custom reamers and dies. I'd rather buy the tools and make stuff.

[Ballistics in Scotland]

I'd just get a .45 caliber throating reamer. You don't want to cut the chamber itself bigger, it won't help (seriously).

For what the OP describes, you are right in considering full chamber reamer unnecessary. An angle visually indistinguishable from 180 degrees between body and neck will be visible if you lay the cartridge on a plane surface, but will do no harm whatever. Most reamer makers supply a suitable piloted neck reamer, but for most bullets you will need one that reams both neck and throat.

Chambers for lever-action rifles, especially old ones, may well have no more than a slight chamfer at the front of the chamber, since the bullet protrusion is severely limited by what will feed through the magazine. In this case you might lose nothing by simply extending the neck alone. If this were the case, you could probably do it more cheaply with an engineer's reamer which closely fits the existing chamber neck. Not the published case neck diameter of .480in., as the chamber is bound to be a trace larger. But 31/64 or 12.25mm. might be fine. A metal or plastic ring at the head or rim would keep it in line, and you should use a machine reamer rather than a hand reamer even if you will turn it by hand, as the latter have a tapered lead.

[Moleman-]

Check out this thread on making reamers. I believe I looked at it before making my first reamer if not, then not long after. http://www.homegunsmith.com/archive/T24986.html

[Cap'n Morgan]

probably be better off renting a reamer

Exactly! Much cheaper than a ruined chamber - Which will pretty much be the guaranteed outcome if using a handheld D-reamer made with file & hacksaw.

[Bent Ramrod]

I check the sharpness of homemade (and rental) reamers by drilling a pilot hole in clear plastic rod and reaming a "chamber" in it. A bad job on the flutes will show as circumferential lines and opaque spots scored in the "chamber," while a properly sharpened reamer will let you see through the plastic as easily as before the pilot hole is drilled. You can even test your cartridges in it for fit.

Work at least as slowly as regular reaming to keep the plastic from overheating and melting. As educational and much cheaper than spoiling a barrel with the same chamber scoring. You can shorten the plastic rod and do it over and over until everything is right.

[bearcove]

I have seen the "machinable" plastic. Price is very high. Do you know which type you use? Plastic is a lot of different things.