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.

[Bent Ramrod]

It was just some kind of clear plastic rod found in a scraps and remainders bin. I don't think it's Lexan or anything exotic like that. The stuff I have melts if you crowd the drill or reamer to much.

If you can find a plastic fabricator or the plastic bin at a junk yard, you ought to be able to find something useful.

[bearcove]

As a side note most plastics seem to machine well. We face and fuse all sorts of pipe. cuts real easy.

[Bent Ramrod]

Oh, yes, absolutely. Nothing like machining plastic to give the amateur machinist delusions of adequacy:-?. The drilling goes smoothly, the boring doesn't taper, the cuts can be heavy, if you don't mind clearing the melted stuff away, and the polishing goes like magic. Then I start on a piece of steel, and it's another story entirely.

But, as the man said, "Excelsior!" :mrgreen:

[Chill Wills]

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.

This is a good idea for a dangerous rookie like myself! I've been using barrel stubs and hunks of scrap steel but I like the idea of clear plastic and working the bugs out of a setup before going for score.

[Hannibal]

It was just some kind of clear plastic rod found in a scraps and remainders bin. I don't think it's Lexan or anything exotic like that. The stuff I have melts if you crowd the drill or reamer to much.

If you can find a plastic fabricator or the plastic bin at a junk yard, you ought to be able to find something useful.


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.

This is a VERY intriguing concept and would have saved me a great deal of trouble not so long ago. If anyone has any idea about what type of plastic suits this purpose, I would be most appreciative if you would post this detail.

[endwrench]

We use quite a bit of Lexan and Plexiglass sheet where I work and they both melt and turn white when cut. I think most any clear plastic would work for this purpose.

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[Sanchez]

Wrong machinery.
Suggest reading-up on the topic before wasting more time, & be advised that proper reamers are frequently rented nowadays.


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

[Sanchez]

Try Lexan(R) or Lucite(R), lubricated w/ hot soapy water & glycerin. Do not use any common petroleum-based cutting fluids on polymers.


If anyone has any idea about what type of plastic suits this purpose, I would be most appreciative if you would post this detail.

[bearcove]

Wrong machinery.
Suggest reading-up on the topic before wasting more time, & be advised that proper reamers are frequently rented nowadays.

I know this. And have read on the topic, was just for discussing that I kept this simple. Want to do stuff that is different. Like a 416 Barnes and 416x2 or 38-56imp...

I don't care how a working shop does gun work for a profit. This is for fun. If I have 160 hours in a 38-56 rifle that I made the reamers for the chamber and dies, threaded , chambered and fit the barrel and spent another month on the furniture that's fine. Doing it is the point. Not dividing the value added by the hours to decide if its a good business venture. My kids will get it some day and scratch their head and wonder WHAT WAS HE THINKING????

[KenH]

I like that idea of using clear plastic as a test for a new reamer. I think I will be trying that. I made a 6-fluted reamer for 50-70 using W-1 rod. All I needed to do was clean up the chamber a bit on a Swedish 12.7X44R so the 50-70 brass would fit nicely.

Ken H>

[bearcove]

I think a piece of round stock, plain ol mild steel would be a better test. Better would be a piece of barrel cut off.

[MaLar]

I know this. And have read on the topic, was just for discussing that I kept this simple. Want to do stuff that is different. Like a 416 Barnes and 416x2 or 38-56imp...

I don't care how a working shop does gun work for a profit. This is for fun. If I have 160 hours in a 38-56 rifle that I made the reamers for the chamber and dies, threaded , chambered and fit the barrel and spent another month on the furniture that's fine. Doing it is the point. Not dividing the value added by the hours to decide if its a good business venture. My kids will get it some day and scratch their head and wonder WHAT WAS HE THINKING????

Any photos would love to see your project!
I make my own D reamers never tested them just did it they work fine specially the straight case reamers.

[Moleman-]

Usually you have enough material left on a barrel to screw up the chamber several times before it's an issue. Whatever you use should have the same land diameter as what you're going to chamber. Since I mostly use standard calibers I have in the past used a Green Mountain gunsmith blank for things like dies, bushings ect. For around $30-$60 they're a good option next to a similar length and diameter of 4140 especially when you factor in it already has the exact precise pilot hole needed for whatever chamber reaming you want to do.

[rusty marlin]

You don't need a grinder to make reamers. I make straight flute reamers and custom saws with my lathe and mill. If you are using an even number of flutes, 4 or 6 you can get away with fluting in a 5C collet chuck, odd numbers of flutes are most easily laid out with a dividing head.

Moleman laid out the process very well.

If you can find a copy of Advanced Gunsmithing by W,F, Vickery, chapter 3 is all about Chambering tools.

[bearcove]

I'll look for that I have the old NRA gunsmithing books and a few other books of that era and the new stuff that is available. The newer the book the lesser the info.

[paul h]

Another option is buy the reamer you want and then sell it on ebay after you've used it. You'll typically recoup 50-75% of the cost of the reamer, can take your time using it, and don't have to wonder if the reamer you rented is sharp or was abused by the previous user as you've got a new reamer.

While one certainly can make a homemade reamer, it is one of the more advanced and precise tasks of machining, hardening, grinding and sharpening and all the skills required to do those tasks to the highest order. Some tasks I'll gladly pay to have the experts do, and chamber reamers is one of those.

[bearcove]

Problem is the stuff I want to do is all wildcat, Reamers and custom dies come quite dear. If I do a 358 win I would just buy a reamer. Use it and put it in the toolbox.

[samari46]

Back in the 20's and 30's if you look at some of the wildcat cartridges they had most of them had a lot of taper. I read somewhere that a lot of the reamers used for such cartridges were made from taper reamers as that was the easiest way to get a reamer and machine it down to get what they wanted.Frank

[Moleman-]

I like making reamers but I wouldn't make one for something that was cheap and available either. I had a custom reamer made back in 2012 by Manson Reamers for $222. I've since tweaked the chamber design a bit two times and just made my own reamer. If it worked great, it didn't cost me $222 each time to test something. If not I'm out a couple dollars for the drill rod and still got to spend an afternoon in the shop which is fine with me. If someone has a mill and a lathe, can read a micrometer & caliper they should be able to make a reamer if they're motivated enough.

[John 242]

Fred Zeglin from Z-hat Custom used to teach a week long class during the summer where students made reamers and reloading dies for their own wildcat cartridges. I didn't take the class and I've only heard about it. I'm not sure what tools they used. Fred has done an AGI video and teaches his class at both Trinidad in CO and MSC in OK from time to time.

You've gotten a lot of good advise here, but if you want to contact Fred, he may be able to give you some ideas or help you out.
http://z-hat.com/taming-wildcats-dvd-how-to-design-and-fabricate-custom-cartridges/

[smokeywolf]

The vast majority of clear plastic found in machine shops today is either G.E. LEXAN, aka "bullet proof glass"; Same stuff you see in banks. Or, it's Poly Carbonate; used in the manufacture of eye glasses because it's "optically correct". Or, it's acrylic, aka "plexiglas".

Poly Carbonate is the one you want for your reamer test. LEXAN works too, and cuts nicer than Poly Carb, but is more expensive.

Sanchez is absolutely correct with regard to using soapy water for a cutting fluid.

[aephilli822]

https://murdercube.com/files/Gunsmithing/The%20Modern%20Gunsmith%20Vol%202%20(Howe%201941). pdf

lots of info in this book

[indian joe]

I like making reamers but I wouldn't make one for something that was cheap and available either. I had a custom reamer made back in 2012 by Manson Reamers for $222. I've since tweaked the chamber design a bit two times and just made my own reamer. If it worked great, it didn't cost me $222 each time to test something. If not I'm out a couple dollars for the drill rod and still got to spend an afternoon in the shop which is fine with me. If someone has a mill and a lathe, can read a micrometer & caliper they should be able to make a reamer if they're motivated enough.
motivated is key I think - I made a 44/40 reamer 15 years ago - just had an old lathe - I ground the flutes off a 9/16 tap - set up an air die grinder on the toolpost - ground the tap to exact dimensions while turning it against the stone (chuck about 250rpm) - took forever and a mess all over the lathe, but it worked! That chamber will take a new shell nice and fired cases will go back into my uberti 66 without sizing - bush mechanic stuff but it worked good. (wouldnt recommend that process) . Made a 22lr chamber reamer a while back from a piece of screwdriver shank - it shrunk a little in the hardening process and I had to finish the chamber with an emery driver on my dremel. Just today I made a .457 reamer to enlarge the cylinder on an 1860 Army colt - looking round the workshop for something I could use that would harden - I took a grade 8 high tensile bolt 1/2inch - cut the head off - centred the thread end and turned the thread off for a shank - reversed and held the shank - centred the other end and turned it 1.5 thou oversize - I put a step in it, turned the first half inch .452 then stepped up to .4585 (only just enough meat in a half inch bolt to do this too) I finish sanded it with 240grit emery to correct size then milled four flutes - have to admit I eyeballed the setup because I was still treating it as an experiment - a dry run if you like - so I put it in the horizotal groove in my mill vice, took a couple of little start cuts to get dead centre - lock the in and out set on the table - the bolt is short and the vice is good so I could cut it without support on the outboard end - cut four flutes by eye - it took a second cut to relieve the material between the flutes - and I left flutes about 1.3 mm wide (that kept the turned dimension) - this is lookin good so I carefully sharpened the flutes by eye with a file just leaving a tiny leading edge at the correct dimension - cleaned it up - still looking good - heated it dull red with the oxy torch and dunked it in oil - I got lucky!! Tried this on an old remington cylinder and its cut .457 neat as can be - its cut easy by hand and clean. I never thought an old bolt would work so well !!!
Joe

[BigEyeBob]

It was just some kind of clear plastic rod found in a scraps and remainders bin. I don't think it's Lexan or anything exotic like that. The stuff I have melts if you crowd the drill or reamer to much.

If you can find a plastic fabricator or the plastic bin at a junk yard, you ought to be able to find something useful.

proably clear acrylic rod called perspex. Will melt and crack if it gets too hot or stressed. Lexan is more tolerant to flex and impact ,but still subject to melting if you go too hard on it when machining.

[BigEyeBob]

motivated is key I think - I made a 44/40 reamer 15 years ago - just had an old lathe - I ground the flutes off a 9/16 tap - set up an air die grinder on the toolpost - ground the tap to exact dimensions while turning it against the stone (chuck about 250rpm) - took forever and a mess all over the lathe, but it worked! That chamber will take a new shell nice and fired cases will go back into my uberti 66 without sizing - bush mechanic stuff but it worked good. (wouldnt recommend that process) . Made a 22lr chamber reamer a while back from a piece of screwdriver shank - it shrunk a little in the hardening process and I had to finish the chamber with an emery driver on my dremel. Just today I made a .457 reamer to enlarge the cylinder on an 1860 Army colt - looking round the workshop for something I could use that would harden - I took a grade 8 high tensile bolt 1/2inch - cut the head off - centred the thread end and turned the thread off for a shank - reversed and held the shank - centred the other end and turned it 1.5 thou oversize - I put a step in it, turned the first half inch .452 then stepped up to .4585 (only just enough meat in a half inch bolt to do this too) I finish sanded it with 240grit emery to correct size then milled four flutes - have to admit I eyeballed the setup because I was still treating it as an experiment - a dry run if you like - so I put it in the horizotal groove in my mill vice, took a couple of little start cuts to get dead centre - lock the in and out set on the table - the bolt is short and the vice is good so I could cut it without support on the outboard end - cut four flutes by eye - it took a second cut to relieve the material between the flutes - and I left flutes about 1.3 mm wide (that kept the turned dimension) - this is lookin good so I carefully sharpened the flutes by eye with a file just leaving a tiny leading edge at the correct dimension - cleaned it up - still looking good - heated it dull red with the oxy torch and dunked it in oil - I got lucky!! Tried this on an old remington cylinder and its cut .457 neat as can be - its cut easy by hand and clean. I never thought an old bolt would work so well !!!
Joe

Grade 8 bolts are good for lots of tooling, it can be hardened easily .I use the 7/8x 14tpi to make push through sizeing dies for cast bullets .Engine head bolts are also good for smaller tooling like reamers and home made boring bars , but they some times need to be annealed before machining .Ive cut the heads off grade 8 cap screws and used them to draw round rod through to get hex shaped rod.

[John Taylor]

When I was doing hobby gunsmithing I made my own reamers. After I started making a living at it I bought reamers. When making my own I found that the reamer will warp under heat while grinding which causes the grinder to take off more than intended. Best to have some kind of flood cooling when grinding. Now if anyone really wants to get into making your own reamers I have and old tool and cutter grinder that will do spiral reamers with it's fancy indexing head. I'm willing to swap it off just because it takes up to much room. This thing is three phase and weighs about a ton.

[Bama]

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
Info can be found by searching for D bit

[john.k]

I have little bit of experience in machining.i would advise anyone trying to make a reamer to buy a piece of "silver steel" for the work.This is barely more cost than a bolt,and is a steel that will take an edge and cut satisfactorily.The packet also has hardening instructions.The other point is that carbon steels are likely to edge soften if ground in T&C grinder,even flood cooling may not stop softening of the fine edge.This is one of the reasons HSS is used.One further point is that if you rock up to the local tool and die shop,and ask for an offcut of this or that,you may get a bit of mild steel and give them a bit of a giggle.

[55fairlane]

Silver steel...... drill rod..... most drill rod or oil Harding tool steels like o-1 oil Harding w-1 water Harding a-1 air Harding, cover it in a soap to keep scale down, heat to non magnetic, quinch, and draw back th e temper.....I am a tool maker.....do your homework on tool steels......as 4140 is not good for sharp cuttingbtools, but great for punches...o-1 is not good for punches, but great for cutting tools

A d-bit type reamed, make one for "roughing" make one for finishing, finish the edges with a good stone, keep your dealers wet while using and keep the chips clear of clogging up the reamed

Aaron