I am sure the big companies use CNC machinery, but I am wondering whether they could be made using regular machinery. Exactly how are they made.

I've seen em made using nothing more than a mill. A tool & cutter grinder would be useful.

the last reamer I made was made from O-1 tool steel.....and I'd not use that again. It worked but M-2 HSS is a lot better. Unfortunately it requires an oven for heat treating and all I have is a torch.......sai la Vie!!!

1. saw blank to length
2. turn rough contour on lathe
3. Mill flutes using an indexer and a milling machine.....4-flutes is the easiest
4. Heat treat.....send to someone with the right furnace and controls.....Some places have a $75 minimum order.....so this quickly kills the joy of making them youreslf!!! If you know a benevolent heat treater wrap the reamer blank in stainless steel foil for him.....
5. using a tool and cutter grinder finish grind the reamer

If your time is worth $10/hour you'll loose money making them!!!!

quote:

Originally posted by DobleTroble:
Here's how I do it myself.

thanks for that link!!

btw, you can use a $25 5c spacer for the dividing head for this work.

jeffe

Maybe someone should send this tutorial to Kiff or Manson; maybe they could learn something.

quote:

Maybe someone should send this tutorial to Kiff or Manson; maybe they could learn something.

??

Doug
I think it was ment as a joke, but that he forgot to put in the thingies.

Doble Troble,
After reading your directions I get the impression that you are using a radial primary, Ie you are leaving the full dia as turned untouched for a primary land, then backing off the secondary a fair amount.
Should make a great finishing reamer, but I bet they push awflly hard for roughing!
I like my dividing head, I can get repeatable primary and seconday backoffs and if I get one that the geometry doesn't work quite right I can accuratly change the numbers and know it changed.

BTW factories use helical reamers - but that's in the advanced course !!!

quote:

Originally posted by mete:
BTW factories use helical reamers - but that's in the advanced course !!!

no we don't, or at least not the ones I am familiar with.

One thing that I was wondering about; you state you cut the taper by offsetting the tailstock. That is valid, but with the one end in the chuck? That would put a helluva bind on the reamer? And wouldn't you be better off using the mill to cut the secondary clearance?

Jim

I've made lot's of rock drills and chisels. Done a whole lot of tempering steels of all kinds in water with a torch.

BUT: have never before this seen reference to heating til non magnetic.

It's the color of the heated metal and the temp of the coolant that makes the temper right, wrong, soft, or too damned hard. Just takes some practice.

I temper the heads of my chisels so they don't mushroom too.

A good bright pink then quench by dipping 2-4 times til black, then cool down will provide a good tough non brittle hardness. IT shouldn't dimple a hammer face either.

For the edge, a medium yellow color then quench in one dunk til cool will provide a near brittle hardness that will hold a long lasting edge.

All this depends on the steel of course. Much of my tool making is made from well sucker rods. Other steels will need to be tried a few times to get it right.

Sucker rod is cheap, lot's of it is around most areas where oil wells are. It come's in 25' sections with a male thread on one end, an female socket on the other. Rod varies, from 3/8", to 2" depending on depth and size of the well. What I got in the 70's was 5/8" and it's dandy for my use. Center punch's from it will almost dent a rail face, nah, not quite, but, will hold a tip for many many marks IF tempered right.

One of my first head tempering jobs flaked off and a good sized sliver stuck me in the brisket. Damn that hurt!!

Keep in mind when making things this way there's quite an area between brittle and tough. Tough will not hold an edge, it has to be quite a bit hotter/harder to hold an edge. But, brittle will chip off, so you don't want the iron too hot, nor the coolant too cold. For homemade tools such as these, water is as good as oil and don't smoke the place up either.

Good luck, and give it a try.
George

quote:

Originally posted by 22WRF:
I am sure the big companies use CNC machinery, but I am wondering whether they could be made using regular machinery. Exactly how are they made.

Now that I think of it there's a company right there in Minneapolis that has the technology and skills to make extremely fine reamers....it's Tool Grinfing Inc.....and they also bore chambers in CNC lathes.....maybe they'd let you in to see their equipment and operation.

The owner is a big hunter and runs a first rate tool grinding shop.....I've used them professionally since the 1970s

When one can get a PTG or Manson reamer for (last I checked) $95 he's bucking for the rank of idiot to make them himself.....there are extremely few shops that have the tools to do as fine a job....the best reamers I ever made are a bit "Rube Goldberg" even though they got the job done....

DobleTroble

Outstanding illustations on "how to." Thank you very much!

quote:

Originally posted by georgeld:
I've made lot's of rock drills and chisels. Done a whole lot of tempering steels of all kinds in water with a torch.

BUT: have never before this seen reference to heating til non magnetic.

It's the color of the heated metal and the temp of the coolant that makes the temper right, wrong, soft, or too damned hard. Just takes some practice.

I temper the heads of my chisels so they don't mushroom too.

When I heat treat small gun parts, I regularly hold the piece over the quenching bath with a magnet and heat the piece evenly until it drops into the quenching solution. This is the point referred to as the "upper critical limit". This is supposedly the point when everything is aligned.

After the quench, I polish the piece so that I can watch the colors as they change, and then bring the piece to the proper temperature, by color, for it's particular use and then quench it.

For rough heat treating on things that aren't that critical, I heat until it's cherry red and then quench. Then I will draw it down from there.

Both way's seem to work fine for their intended purpose, but for the more critical parts, I like the magnet because when done right, it provides a bit more uniformity to the grain structure.

quote:

Originally posted by georgeld:

BUT: have never before this seen reference to heating til non magnetic.

give it a try.
George

George,
This is how O1 is done.. but at temps, all steels become austenite, or non-magnetic...

or, essentially, that's how can tell a temp and condition of a metal, rather than color, as color can vary with ambient light.

jeffe

It’s called the Curie point... when a ferromagnetic substance loses its ferromagnetism due to being heated. For iron that occurs at approximately 760C or 1,400F.

Boy, I'm glad you guys find this interesting.

I've made a bunch of weird wildcat reamers using these methods, mostly on shot-out Mauser barrels left over from sporterizing projects.

Rusty, some of the reamers I've made cut better than others, but none of them cut as well as commercial reamers I've used. You're absolutely right about some of them pushing hard for roughing. I'm trying to comprehend "radial primary" but am not there yet. Do you have a suggestion about how to improve roughing performance?

Are you suggesting that it might be a good idea to make both a rougher and a finisher, and for the rougher to grind relief all the way through, essentially eliminating the primary land? I might have to give this a try.

Jim, I agree that using a dog between centers is probably a better approach for cutting the taper. I suppose my set-up is one of convenience. I only chuck-up the tip of the blank which may help keep stress down. As I've gained more confidence with the mill I've started cutting relief with it, but after you get all the way to this point there's severe pucker factor.

I got a rotary table with dividing head for father's day. I'm looking forward to the chance to figure-out how to use it.

I will freely admit that this is a big waste of time, and commerical reamers are cheap given the time and effort required to make your own. But if you're a die-hard do-it-yourselfer like me, shooting a small group with a rifle chambered in your own wildcat made with your own reamer comes in way up there on the satisfaction scale.

quote:

Originally posted by DobleTroble:
I got a rotary table with dividing head for father's day.

How do you rate??? I got a shirt and a piece of a$$ and they were both too big! Spare me the PM Jeffe. I was just kidding...

"How do you rate??? I got a shirt and a piece of a$$ and they were both too big!"

quote:

Originally posted by malm:

quote:

Originally posted by DobleTroble:
I got a rotary table with dividing head for father's day.

How do you rate??? I got a shirt and a piece of a$$ and they were both too big! Spare me the PM Jeffe. I was just kidding...

LMAO!!!
you can send me the shirt!

Appreciate the explanations guys.

Rick/Malm: Guess I just ain't old enough yet!!
magnetic loss with heat is a new one on me. And I've got a AA in metalurgy, must have been sleeping that class.

What IF: the iron's not magnetized? OR do you just hold the steel item being heated with a magnet? Explain this a bit deeper please.

Don't think I'd want a gun to have anything magnetized on it. What am I missing here??

George

George,
Morning - it's not magnitized, it's non magnetic. DO a search on austinite and "heat treating O1 toolsteel" ..

Essentially it's like I said, what you may have been defining as a color, the material changes properties...

j

quote:

Originally posted by georgeld:
Appreciate the explanations guys.

Rick/Malm: Guess I just ain't old enough yet!!
magnetic loss with heat is a new one on me. And I've got a AA in metalurgy, must have been sleeping that class.

What IF: the iron's not magnetized? OR do you just hold the steel item being heated with a magnet? Explain this a bit deeper please.

Don't think I'd want a gun to have anything magnetized on it. What am I missing here??

George

This is for all those who are curious about this specific heat treat topic.

Steel at normal temperature has the carbon content, the chief hardening agent, in a form called "Pearlite". When the steel is heated, a structural change occurs and the pearlite becomes "Martinsite", or, hardened carbon. If the steel is allowed to cool slowly, the Martinsite will revert back into Pearlite.

The steel, if heated enough, will reach a point called the "Decalescence" point, or, the upper critical limit. This is a measurable point when the steel continues to absorb heat without any notable rise in temperature, although it's immediate surroundings will be hotter than the steel itself.

Steel cooling from such a high temperature will reach a point where it will actually "increase" in temperature although it's surroundings are much cooler. This point is called the "Recalescence" point, or, the "lower critical" limit.

The difference between the upper and lower points is between 95 and 200 degrees F, and is dependent on the carbon content of the particular steel.

These critical points bear a direct relationship to the hardening process for steel. Unless the temperature reaches the "Decalescence" point so that the pearlite carbon is changed into martinsite, no hardening of the steel can occur.

And unless the steel is cooled suddenly before it reaches the "Recalescence" point, preventing the transformation back to "pearlite", the hardening will not take place.

The "Decalescence" point marks the correct hardening temperature for the specific steel. But, how do we know when our particular piece of carbon steel has reached the "Decalescence", or upper critical limit without a pyrometer? The steel becomes "Non-Magnetic" at the precise moment that the change occurs. This is when the piece of steel must be suddenly cooled if hardening is to occur. And, it must be cooled quickly, to prevent the piece from reaching the "recalescence" point.

That is why as I mentioned, that I hold the small pieces with the magnet, over the bucket of cold water while evenly heating the piece with the torch. When it reaches the "Decalescence" point, it falls from the magnet, into the cold water quench which makes it as cold and as hard as my ex wifes heart. Once it is hardened, I determine the correct temper for the parts intended use, and slowly heat the piece to that temperature (by color) and quench it.

For complicated and real critical parts, I let the professional heat treaters worry about that.

quote:

Originally posted by georgeld:BUT: have never before this seen reference to heating til non magnetic.

George

An interesting bit of trivia along these lines
Weller soldering irons use this property as the "thermoststat" on their pencil type soldering irons. There is a magnet in the grip portion, and the different tips have a specific alloy "button" at the base that goes into the handle. At the tips rated temperture the button becomes non-magnetic and the magnet lets go - which breaks the current to the heating element. When the tip cools a bit the magnet reattaches and reactivated the switch to the heater. So it's not really that unheard of.

quote:

Rusty, some of the reamers I've made cut better than others, but none of them cut as well as commercial reamers I've used. You're absolutely right about some of them pushing hard for roughing. I'm trying to comprehend "radial primary" but am not there yet. Do you have a suggestion about how to improve roughing performance?

If you will in indulge me for a moment...
"radial primarly" or "radial land", this is the face that is running around the diameter of the hole, it is directly behind the cutting face of the reamer (the flute). With a straight or back tapered reamer a radial land is allowed and some times desired so just the tip of the tool will cut while the radial land acts as a guide to prevent the tool from wandering. This is esspecially important in materials with voids (like castiings). Because the radial land acts like a skid plate floating the body of the reamer this style is not recomened for forward tapered reamers, ie chamber reamers. In order for a tapered radial land reamer to cut, it must be pushed very hard into the work where material is squeezed out from under the radial primary and then sheared off by the cutting edges. It will create a beautiful burnished surface, but it really won't cut well. I can understand why you make reamers like this, to do them by hand as they are commercially ground would be a bitch.
Commercial reamers have a ground rake angle behind the cutting edge, this is the Primary Relief Angle, Generally this angle is 7 +/-.5 deg, this land is about .032 wide. Behind that is a secondary relief angle of anywhere from 15 to 18 degrees and its falls off into the flute of the next cutting edge. The relief you put on by hand could be considered the secondary relief angle, if the primary angle is left at zero (radial land).
The primary relief angle allows the cutting edge to bite into the work. Think of it as a lathe tool, if there was no rake angle under the cutting edge it would float on the work, but when there is sufficiant rake angle the tool will cut. The thing is, this primary relief has to follow the form of the cutting edge all along the contour. Without a tool grinder this is exceadingly difficult, in a milling machine, its an exersize in futility. Not to say it can't be done, but its a lot easier to beg, borrow or rent a reamer in the long run.

Better?

Rusty:
Way back in the mid 60's when I was running a lathe for a living, we ground our own tools. I got pretty hot stuff on a brand new Hardinge Chucker. Had to give it up due to ulcers from the tension of the tight tolerance's I was living with. Would go home and tremble for hours after work. Hell, I was only 23!! Was holding +-.0002 on multi journaled pins made from half inch stainless. Much like a miniture crankshaft. Had two mains, one on each end, and three throws in the middle. Tip was thd 1/4" 20, half inch head slotted for a screwdriver. That's all I made for months. Got to the point I couldn't keep any food down and was getting mighty sick and weak from it. The company doc tested me for ulcers. 45 yrs later I still have belly problems with some foods. Ain't it hell??

anyway, I watched old Nick grind milling tools on the grinders. Impressive! and many of them were twist too. Sure wish he was still around I'd have him make some dandy chamber/die reamers. Too late smart as they say, right?

Malm: You saying to heat the metal til it falls off the magnet into cold water. Then just heat it up to the correct color?

At that point, doesn't it need to be quenched again?

I've made a ton of tools and am pretty handy at it. But, only heat to color I want, then quench it. For tougher tools, don't chill it til cold. Just take the most heat out and leave it still too hot to touch. IF an edge temper is desired, then quench it til it's plumb cold.

Many times I've used these to peel layers of steel off a surface, or joint edge instead of grinding, mostly in place's a grinder or file can be used.

Ok, a question. Am badly in need of a tool grinding stone for lathe bits and carbide bits. What and where can I get them? Only want the two wheels, need to get a grinder first, then the wheels to fit. But, gotta get them and soon.

Thanks for the education, never wasted, but, too late to use on the job as I've retired many yrs ago. Am still interested and do what I can, need to in my shop.

George

Rusty,

THANK YOU!

That was a great explaination that even I can understand. I'm doing a lot better thinking of it as a lathe tool with a skid plate.

I may have to try to hand grind primary lands to 0.03. With patience it should be possible to get closer. Maybe I can come-up with some sort of jig to help.

Thanks again, Rusty.

quote:

Ok, a question. Am badly in need of a tool grinding stone for lathe bits and carbide bits. What and where can I get them? Only want the two wheels, need to get a grinder first, then the wheels to fit. But, gotta get them and soon.

Here is the Enco page for diamond wheels for bench grinders.

or this is a very nice addition to the shop... need to get one myself grizzly tool grinder

Very carelessly. FNMauser

quote:

Originally posted by georgeld:
Malm: You saying to heat the metal til it falls off the magnet into cold water. Then just heat it up to the correct color?

At that point, doesn't it need to be quenched again?

Yes sir. Bring it up to color and quench it.

malm!

Your ex actually has a heart????
Break off a piece and mail it to my ex, would you?
Maybe I can get permission to see my step daughter graduate from high school next year. (And quench the ex wife's head in a pasta jar of oil )

quote:

Originally posted by lawndart:
malm!

Your ex actually has a heart????

Well, that's what they think it is. I would need to see an actual running EKG strip to be sure.

quote:

Maybe I can get permission to see my step daughter graduate from high school next year.

Unless there were a court order preventing it, I would just show up. Maybe position myself in the seat just in front of the ex.