[ThomasAlva]

I am trying to make some miniature train wheels to ride on some round stock.

I want to know where I can buy a lathe cutting bit that will allow me to make such wheels.

I don't need a quarter round, I need a half round. Thanks in advance for any advice.

Regards. :banana:

[RICHARD ZASTROW]

A round tool will leave a half round if you plunge straight in the rim of the wheel. What size round do you need? Lathe inserts are sized at least down to .187" dia.

[ThomasAlva]

A round tool will leave a half round if you plunge straight in the rim of the wheel. What size round do you need? Lathe inserts are sized at least down to .187" dia.

OK, then I can use a round tool as well. Know any online suppliers?

[RICHARD ZASTROW]

Seco-Carboloy inserts: RCGS, RCMM, RCMT, RCMX, RNMA, RNMG

www.secotools.com ecatalog turning inserts

[ThomasAlva]

Seco-Carboloy inserts: RCGS, RCMM, RCMT, RCMX, RNMA, RNMG

www.secotools.com ecatalog turning inserts

I got to navigate that site a while. when I type in any of those above acronyms (I don't know what they mean, sorry) into the search, it doesn't list anything.

[RICHARD ZASTROW]

Those are the code letter (catalog numbers) of the inserts.
www.sectools.com will get you to the site.
click on "ecatalog" to get to tool type selection. Click on "turning".
select & click on "turning inserts". Then you will have to scroll around to the round insert pages where you will find the above combinations of letters with accompanying charts describing the inserts size etc.

[ThomasAlva]

Those are the code letter (catalog numbers) of the inserts.
www.sectools.com will get you to the site.
click on "ecatalog" to get to tool type selection. Click on "turning".
select & click on "turning inserts". Then you will have to scroll around to the round insert pages where you will find the above combinations of letters with accompanying charts describing the inserts size etc.

Thanks!
Done

[Mcgyver]

If I'm understanding you properly, you plan on using it like a tangential cutter? won't work, no clearance. just make some up out of drill rod then you can cut the clearance in. better still use a boring head as an up and over radius cutter. here's a pic of a tangential style one i made many years ago, made a set off wheels for a tube straightening mill (for smallish copper tubing) but if was doing it again the up and over is the way to go imo

[RICHARD ZASTROW]

Mcgyver, Your tool/method obviously works. Just FYI, the button tools will also work. If you look at the www.secotools.com site, page 133 (turning-toolholders, external) toolholders TRAOR, TRAOL AND TROON , all use button tools. We used these to plunge but more often to contour deep slots in forming rolls. Those little buttons will suprise you. Get the SECO rep to get you a freebee to try.

[Mcgyver]

ah I see. when he said round tool bit i thought he was looking for round hss instead of regular sq, hence concern over clearance, obviously not an issue with inserts. thanks for clarifying

[ThomasAlva]

If I'm understanding you properly, you plan on using it like a tangential cutter? won't work, no clearance. just make some up out of drill rod then you can cut the clearance in. better still use a boring head as an up and over radius cutter. here's a pic of a tangential style one i made many years ago, made a set off wheels for a tube straightening mill (for smallish copper tubing) but if was doing it again the up and over is the way to go imo

Yep, that's exactly what I'm trying to make, minus the broached keyway.

So.. if I take some drill rod and cut off the fluted end, and just leave the shank, the shank side will be sharp enough to cut into spinning round stock?

I just have to be careful to have the drill-bit shank locked down pretty tight, right?

I'm very much a novice at this, so if I'm exposing my ignorance... then indeed my ignorance is exposed.

[riverrat]

I know this may sound "stone age" to some of the guys here,,,, but
why don't you buy a hss blank and grind the damn thing?
thats how it was done before carbide tools, cnc, etc....
those carbaloy tools are good, but pricey for the hobby guy.

[Mcgyver]

Yep,So.. if I take some drill rod and cut off the fluted end, and just leave the shank, the shank side will be sharp enough to cut into spinning round stock?

I just have to be careful to have the drill-bit shank locked down pretty tight, right?

Thomas, drill rod is tool steel, silver steel to our UK friends. basically you buy it annealed (soft) machine the shape you want, then heat it red hot with a propane or O/A torch and quench it (oil/water or air depending on what type of drill rod, ie O1 quench in oil). then (after tempering) it is hardened and can be used to cut metal including steel.

My reason for suggesting this rather than using a straight cylindrical shape as a tangential tool is that it needs some clearance to be able to cut. you see the slight conical section below the top of the tool bit in the holder? this is the clearance i added by machining the drill rod prior to hardening.

If you are really new at this this may seem like overload, but hang in there, its worth learning, not that tough and making your own cutting tools is a valuable home shop skill. there are times when making a cutter is the only practical way to do something.

riverrat however probably has the easiest suggestion, just grind the end of any old hss bit to the desired radius. between grinding and a coarse wet stone you can put a decent radius on it. probably the way to go

what you are working with (lathe), how big a radius you require and what material you are cutting ? A wide profile plunge cut might be more than a small bench top lathe is capable of (then its build a radius cutting attachment time)

[Degrom]

If I'm understanding you properly, you plan on using it like a tangential cutter? won't work, no clearance. just make some up out of drill rod then you can cut the clearance in. better still use a boring head as an up and over radius cutter. here's a pic of a tangential style one i made many years ago, made a set off wheels for a tube straightening mill (for smallish copper tubing) but if was doing it again the up and over is the way to go imo

Hi, Mcgyver...

I am impressed with this tool. I want to make the same round former as the one you made in the picture. I just want to use it for bending small diameter steel rods and tubing.

Could you please explain how this works. (I bought a new lathe 2 weeks ago and I am still learning all the tricks of the trade.)

Your input would be mush appreciated.
Bert.

[Mcgyver]

Hi Bert,

the roller in the above picture is from a tube straightening mill I made....I've also made a tube bending....multiple photo's of both are shown here:

http://bbs.homeshopmachinist.net/showthread.php?t=24051

i made them to deal with making tight bends in copper tubing for models. if you are bending steel, the forces will be a lot higher and you should consider hardening the parts, both the rollers and axles.

this project is not a trivial undertaking, then again any project is just a collection of steps, but if you're a rank beginning this might not be the best place to start - its a longer build with a very low duty cycle .

not sure what you're trying to bend, but if its just small dia steel stock, there's no need for a profiled die. you can do good work with pins and cylinders bolted to something flat. A lot of the complexity of my tube bender (the eccentric clamping axle, straight shoe style die etc) is there to maintain the circular profile (largely for aesthetics) through out the bend - tough to do with soft copper. these things wouldn't be as much of a concern with steel

[Degrom]

Hi Bert,

the roller in the above picture is from a tube straightening mill I made....I've also made a tube bending....multiple photo's of both are shown here:

http://bbs.homeshopmachinist.net/showthread.php?t=24051

i made them to deal with making tight bends in copper tubing for models. if you are bending steel, the forces will be a lot higher and you should consider hardening the parts, both the rollers and axles.

this project is not a trivial undertaking, then again any project is just a collection of steps, but if you're a rank beginning this might not be the best place to start - its a longer build with a very low duty cycle .

not sure what you're trying to bend, but if its just small dia steel stock, there's no need for a profiled die. you can do good work with pins and cylinders bolted to something flat. A lot of the complexity of my tube bender (the eccentric clamping axle, straight shoe style die etc) is there to maintain the circular profile (largely for aesthetics) through out the bend - tough to do with soft copper. these things wouldn't be as much of a concern with steel

Thanks for posting the link Mcgyver... I found it very interesting and I must say you can be proud of your work!!!

Lots of guys on the Lathe Newsgroup also like your work...

[Mcgyver]

thanks for the kind words