Drill rod questions

[Wolfer]

I need some schooling on drill rod. Mostly used for one time use as D reamers. Out of O1,A2 or W1 which is the easiest to harden.
In searching the net there are lots of info but watching videos it seems most people don't do the oven tempering step. Just heat and quench or with A2 just heat.
Im confused.

[Moleman-]

I use O1 and do not temper. I tried it once and the thin cutting edges annealed more than the body and that reamer did not cut as the cutting edges ended up too soft. Now I just harden and know if I drop it on the concrete floor I'll have to make a new one.

[Der Gebirgsjager]

I've never made reamers, but for parts like firing pins, etc. I use oil quench rod.

[Wolfer]

Do you then anneal it back to straw or just leave it hard?

[Der Gebirgsjager]

I draw it back some in an oven. How much depends on the size and thickness of the part.

[Moleman-]

For chamber reamers I just leave them hard.

[waksupi]

I use an oven to draw back 0I. It can be done with a torch if you can read color correctly.

[44man]

Air hardening is tough. Can't anneal. I use oil hardening and temper in the oven. To leave full hard will break a cutter. Every steel is different.

[colchester]

I like 0-1 best for ease of use

[bigdog454]

I like Air hardening, easy to harden and works OK. but that's just my 2 c.
BD

[Wolfer]

Mail man brought me a stick of 0-1 today. I'll fire up the forge and give it a go first chance I get.

[Moleman-]

Are you making a chamber reamer perhaps, and if so what caliber?

[Wolfer]

My first plan is to build a cherry/ D reamer for a boolit mold. The last one I made from a piece of key stock hoping it would cut aluminum. The combo reamer/cherry worked but dulled pretty fast and left the cavity undersized at the front band. I built another reamer from the back of a drill bit and tried to ream it by hand. Ended up with a gouge in the side so now it's going to become a larger mold perhaps.
I am thinking about making a D chamber reamer to make a couple whack a mole type loading tools. I don't really need them I'm just looking for projects.

[Moleman-]

Sounds fun. Never made a bullet mold yet, but I've been thinking about it. Another trick is to make a 14"-18" or so extension for your drill press (to keep heat away from the chuck) and run the reamer at low speed while heating and quenching. I have a floor model drill press and just swing the table to the side and set the used oil jug on the base until ready. Then run it in the oil until it cool enough to handle.

[44man]

I left some rod full hard when instructions said it did not need tempered. It broke edges in aluminum. Had other steel hard at the start and said no hardening needed. Wrong, Edges ate off fast.
I stay with oil hardened now and temper at 300° in the kitchen oven for an hour, let cool slow in the oven.
Air hardening will get hard with heat from cutting and ruin tools. I cant keep coolant to flush and cool on my lathe. Need a heavy flow.
To harden a cherry without warp, I heat in the drill press and open the chuck to drop in oil. If you quench crooked, you get crooked.

[Shiloh]

I use O1 and do not temper. I tried it once and the thin cutting edges annealed more than the body and that reamer did not cut as the cutting edges ended up too soft. Now I just harden and know if I drop it on the concrete floor I'll have to make a new one.

Most are like this. Drop it and it is scrap.

Shiloh

[Moleman-]

There is a formula for how deep to lay out the flute or flutes, but I've found .005" to .007" below centerline with a standard 4-flute end mill works best for me. That leaves you with a sharp edge that is as strong and well supported as it is going to get. The reamer in the wooden box is one I've loaned out a few times. Got it back once with spin marks on it were the guy had held it with a drill chuck in the tailstock and either fed in to fast or didn't clean out the chips. Other than the chuck rash just above the square stub there appears to be no damage. I've used it for 5 or 6 barrels and have loaned it out 3-4 times and it is still sharp. I doubt it will last as long as a commercial reamer will, but it's lasting longer than single use with dark cutting oil.

[Ballistics in Scotland]

I am pretty sure that commercial chamber reamers are tempered a little. Unmodified full hardness will be suitable for only very light use, since even if it doesn't break, you can get very fine chipping at the edges.

Key steels are designed to break, so that you will sacrifice a cheap key rather than an expensive shaft. But I think even mild steel can be hardened with a case hardening compound, well enough for slow cutting of a mould cavity in aluminium or brass.

A D-section will warp much more easily in quenching than a tool with symmetrical fluting, but one of its advantages is that it is quite easy to refinish the flat or slightly concave side after hardening. I have had good results with a carbide pin gauge, bought from China on eBay for about $6, which lets you out of that problem.

Torch annealing won't make the cutting edges any softer than the rest of the reamer if you let the heat creep upwards from a heated shank. But that will require slow, progressive heating, with the cutting part protected from airflow. Oven annealing is better. There may be molten salt baths which would do it, but molten saltpetre, sometimes very good for other parts, has too high a melting point.

[Wolfer]

While I have a weed burner that would probably work my plan all along was to use my coal forge to harden and the kitchen oven to temper.

Looks like my first project will be a "chamber Reamer" for a set of lee type reloader for my 34 Roberts. Made the body today out of a section of 8mm barrel. Hole in the barrel was noticeably off center so I indexed to bore and turned it to center. Got it step drilled, just need to make a reamer.

By the time I was done I'm sure it would have been easier to start from scratch than to try to use the barrel.

[Wolfer]

188765
I decided to make a regular reamer instead of a D reamer. I don't have a mill, I cut the flutes with a dremel cut off wheel in a die grinder.
Hardening and tempering went good. It cut as good as I expected but I wasn't expecting much.
Certainly will need a little honing/ polishing. Clymer or PTG shouldn't be worried yet.

[Moleman-]

Good job, if it cuts it doesn't matter how you got there. My first reamer didn't cut well. With a little bit of creativity you can cut the flutes on your lathe. I've seen where guys held the reamer blank in the tool post and an end mill in the lathe, and also held it in the lathe between centers as normal and used the bull gear to index the reamer and cut the flutes with an die grinder held on the tool post.

[M-Tecs]

Some good basics on heat treatment here. https://www.crucible.com/eselector/general/generalpart2.html

[country gent]

We cut blind keys in the lathe with a boring bar and lathe bit facing forward touch and back out (leave spindle in lowest gear) then run in with table take a couple thousandth each pass. Same could be done to cut flutes. set a tool high and run in a few thou each pass and rotate for next flute.

[Wolfer]

That should work pretty well, especially on straight reamers. A bottle neck might be a little more difficult but could certainly be done.

My harbor freight cross slide vise should be here today. It and an angle plate from grizzly should let me do some light milling.

[44man]

I use a Vertex to cut flutes on cherries. Any angle is perfect.