machining 52100 (bearing race)

[DanASM]

I have a few bearing races to quote but I have not machined 52100 before. I know a lot of bearing races were ran on multispindle screw machines in the past, but the prints say they cant have chatter on the O.D. So i suspect they have had issues in the past with it. I would think a form tool may chatter a bit but a swiss sliding head lathe could single point it without chatter marks.

I know there is a big industry relating to bearings and with a little more experience I might be able to put some of these jobs on my Brownies. QTY's are right at 5k,10k,15k per part #. I would hate to say no to them.

The material would be cold drawn annealed when its machined. what is comparible to this material as far as machinability?

Thanks,

Dan

 

[crossthread82]

Are you just rough machining them, then send to be heat treated, then sent to a grind shop for finish? I couldn't imagine a bearing race would just be turned.

If it's annealed I would think it should behave something similar to 4340, but that's just my speculation I've never machined it personally. I'm sure someone more knowledgeable will chime in.

 

[EmGo]

I have a few bearing races to quote but I have not machined 52100 before.

It turns fine but is hard on tools and doesn't like to break a chip. By hard on tools, I mean wear. Carbide is not that much of a problem but if you are using hss in a screw machine, more so. I never had problems with chatter but chip control, for sure.

Once you get it dialled in it's fine but getting to that point can be interesting.

Quoting that many on a first try is going to be exciting If you quote for 4340 then add some for extra hassle, should at least break even. 20% maybe ?

 

[gbent]

I just pushed some annealed through by hand on a vertical band saw. I'd guess 20 to 40% tougher than 4140qt. FWIW.

 

[adh2000]

I’ve turned a lot of 52100 on manual lathes. What EG said. Long stringy swarf that winds around and gets caught in everything.

 

[DanASM]

I am seeing speeds and feeds similar to 304/316 SS, which I have lots of experience with. I am thinking it will run slow and tools will wear quite a bit.

It says "Seal seat must be smooth and free of chatter".

Sounds like a job that I cannot walk away from for very long. Slower speeds means more billable hours for me though.
Parts are about .500" O.D. with .250" hole and .another with .305" hole.

EDIT: I would probably get a circular REX 76 tool for this job. Something I can keep sharp and will last a while. I just shattered a stick carbide form tool and if I have to buy 2 of them, then it makes sense to spend more on a circular tool that I can resharpen a bunch.

Form tools cost me...
Carbide Stick - $230-$250
Rex 76 Circular - $400
Circular tool with 4 carbide faces - $500

These are for my biggest machines 1-1/4" - 1-1/2" Capacity.

 

[Ox]

I've never ran in a screw machine, but ran a fair amount of it on the CNC's.
With carbide - I didn't find it to be all that much of a challenge at all.
Maybe b/c I likely started as slow or slower than needed, and never had any wear issues.

Is the customer ABC?


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Think Snow Eh!
Ox

 

[Mtndew]

It cuts fine, we've cut tons of it, both mill and lathe. Just treat it like a 4150pht and you'll be fine.

 

[DanASM]

My dad told me it would be really stringy and chips would be an issue. I would be fighting with it a lot and would be chained to the machine.

The material specs dont scare me away. Slow and steady is what works on my machines.

I am going to show it to the swiss guys down the road in a bit. They have Citizen A32's that could run it no prob.

I did have cnc guys tell me they break a lot of tools in stuff that I regularly run without issues. They told me the SFM they were running at and I told them to cut that in half. The response was "then it will run too slow". Got to balance the loss of tooling vs increases cycle times.

The material supplier is Sullivan Metals and it looks like it is 220-240 ish bhn.

Ox- not ABC, but just north of NYC. They seem pretty big.

We have a Timken in NH and NH Ball Bearing nearby as well. They have turning departments in house.

 

[Ox]

Sullivan is where we git our from too.

But it would seem that if you were running for Timken, that they would supply the material.

If you would run it out of 1018 on your machine, go ahead and try this.
Other than maybe slowing it down a bit, I see no reason that it shouldn't run.
It sounds way worse than it is for sure!

Seems like it may want to make a boring bar sing a little worse than others?
Maybe ...


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Think Snow Eh!
Ox