This is good stuff. If you have access to a CNC, or a competant machinist, and an interest in wildcats, this'll be your ticket.

Lets point out one major flaw. My time is worth more then that.

Now for everything else he either did wrong or half assed.

0-1 is not a good tool steel and if you are going through all this trouble make something that will last.

Complete lack of grinding the cutting edges. yes he relieves them with a dremel of all tools but the flutes are still just the turned dia.

That reamer would be good for maybe one use and thats it. The guy has the right idea just lacking the correct geometry on the cutting edges.
If he'd spent some extra time he could have made it much better. But again for as little as a reamer costs I'll buy one or rent one.

quote:

0-1 is not a good tool steel and if you are going through all this trouble make something that will last.

Honest question- would you provide which material(s) are appropriate?

Thanks.

Nothing that can be heat treated in a home shop.

M2 HSS or M42 HSS 5% cobalt. They require very high heat treating temps and long soak times

If you had a heat treat furnace and some time to kill A-2 or D-2 would work but they are not tool steels used to make cutting tools with. Although they would be a far cry better then drill rod (O-1)

I haven't read the link, and I know almost nothing about machining(just ask kcstott... ) but IIRC P.O. Ackley had the answer to making a DIY wildcat reamer.

As I recall a reamer was made by turning a solid piece of steel that matches the desired chamber dimensions. Then this "unfluted reamer" was milled to half thickness down its centerline(maybe just more than half thickness?) The cutting edge was then hardened with a torch.

The resulting reamer was said to cut a smooth chamber, but took quite a bit of feed pressure to cut.

I doubt this type of reamer would last long, but then how many chambers is the DIY guy going to cut?

Jason, you've described a 'half-reamer', and described it very well. The procedure is to first harden it and then grind the middle part away to just below the centerline, of course taking great care not to overheat the steel. An acceptable procedure for perhaps one very special reamer and one very special chamber but quite time-consuming and NOT cost-effective.

We were taught to make simple 4- and 5-flute reamers in class but at that time the school had no T&C (tool & cutter) grinder so therefore no chamber reamers. It's a simple matter for most machinists to fab a shop-made tool-post grinder and that can serve almost as well as a T&C grinder, just takes longer.

Re grinding flute relief with a hand-held grinder: I've done it, but I cut my hand-grinder teeth in the tool room of a heavy hardware manufactory, hand-grinding the reliefs for large drop-forging blocks as well as reamers & cutters. It takes 2 STRONG hands and lots of practice and 100% close attention, I don't suggest it for the inexperienced.
Regards, Joe

Interesting thing about half reamers. When the first edge gets dull just reverse the headstock and the other edge will cut. Run it upside down to help clear chips.

I made a five flute .223 reamer out of O-1 last winter. I did it because I wanted to learn and I would have good examples to compare the results to. I turned the blank, cut the flutes, hardened and tempered it, and then relieved and stoned the edges. The only thing I would do different would be one less flute because they got kind of thin. The reamer cut on four of five flutes and cut a nice smooth chamber that fit my brass well. I wouldn't use it for production but I see no reason why it shouldn't cut four or five good chambers. I've got an idea for a wildcat that I will use this method for both chamber and sizer die and I'll put the $250 I save into a better barrel or a scope.

OK this is not a chamber reamer but here is how I made my first resizing die for my 20 Tactical in a simple craftsman bench lathe:

I used 3 separate reamers- one for the neck, one for the shoulder, and one for the body.

Apologies as I don't have the dimensions with me and I've forgotten many more important things since I did this! However, the neck was a straight reamer that I may have reground. The shoulder was 40 degrees IIRC. There are 40 degree countersinks that could have been used pretty much off the shelf but I reground a drill bit and it worked fine. The body reamer has a taper and I was able to put in an offset and grind that too.

As I said, it was all done on an 80 year old bench lathe driven with a washing machine motor without much in the way of accessories, just a bit of care and headscratching. My grinder was a ryobi dremel type tool (grind once, measure twice, grind a little more, measure again. Repeat until done)

I always joke about projects like this, if you are doing it to save money you'd be better off mowing lawns and buying what you want but if you just want to make something with your hands using the limitations of your equipment there can be a lot of options.

O-1 works well for shop made reamers.

My gunsmith is 79. He showed me once, about thirty years ago; how to make the single-flute reamers. He called them "silhouette" reamers. Back then, they did not have the internet or all the options we do these days. Quite often, the customer wanted some special design. They would draw it out, turn the silhouette to match, and then mill the shape halfway. If you only want to cut a chamber and the dies, it is perfect.

Your time may be worth more than that, but not if it takes a couple weeks to get the reamer and dies and you are working because you need to make a living. Too many "gunsmiths" these days would be better described as parts assemblers.

Rich

I posted the link, because a wise man once said:

quote:

Knowledge not shared is lost

This site is global & not everyone can get a reamer fast.

I built a 2 1/2-12 tap Friday far a 500 ton injection press that had blown a hydraulic seal plug. I made a new plug as fast as I could but the I.D. threads were buggard-up so the needed chased....no such tap.

I made one from what I had and FAST. S-7 was on hand but not long enough so I welded a 1" shank of H-13 onto the S-7 with TiGtectic680 cut the threads, milled 8 flutes and flame hardened.

The press was up and running and back to making $8 per minute for the company. As a machinist/welder I have learned that the perfect fix isn't always the fastest most practical. When a machine is down $8 to &10 per 60 seconds stacks up fast.

As for O-1.…it’s a go-to standard in most shops as a fast custom one time tool.

I'm not arguing the Knowledge Just the materials and technique. I never said it wouldn't work either I just said it wouldn't last. Ok if I had nothing better to do on a weekend and no better material and refused to rent or borrow a reamer sure one made of O-1 would work in a pinch. But I still stand buy my original statement that if I'm going to tie up the better part of the day whittling on this thing I'm going to do it the best way I can out of the best materials I can get. I want it to last. I understand we all have access to varying levels of machine tools. I just couldn't see spending eight plus hours on a piece of O-1 just to get a few minutes of use. Hell flame hardened A-2 would be better.

Granted in Teds case Anything you can do to get that machine up and running is saving money. The faster the better.

Ted, too bad that process hadn't been filmed or photo'd, I'd enjoy watching.

How much would you enjoy watching? I will have the boss pull the security MPeg from Friday’s big brother cams. We work every day under security surveillance.

I could post a picture of the big home made tap if you want.

My last work-place lost one million dollars per day when shut down. We didn't have time to fiddle-fart around with the mails if we needed a part (unless required by federal law).
Regards, Joe

Ted,
Sounds like you're working for an injection molder and I would guess you're a moldmaker. I just retired from that business after about 40 years. I really enjoyed my career in that field and wish I could go back and do it over again.

Yes sir, Journeyman Moldmaker

A picture of half-reamers for those who have not seen one.