Looking for 7" dia thick wall steel tube for bearing housing

[Milland]

Recently it appears that tube and solid stainless are similar in price. I just switched a part over to tube. We'll see how much I hate myself when I see how out-of-round the tube is.

Oh, you won't hate the delivered OOR. You'll hate the after-machining OOR...

 

[Garwood]

Seriously?

Yes. How do you put a mirror finish on your 1018 parts?

 

[BT Fabrication]

Around here that 7" by 6" long would be about $80 per....... CDN! so change the 30% exchange rate and its under 60 bucks usd.

 

[PackardV8]

FWIW, we just went through this exercise and savings from starting with tube were illusory. Go with good bar stock which you know works with your machine and tooling.

Another FWIW, a bearing housing usually doesn't benefit from more expensive stock. OEMs use cast iron where they can. The bearing shell provides the strength and the wear resistance.

 

[Cole2534]

Another FWIW, a bearing housing usually doesn't benefit from more expensive stock. OEMs use cast iron where they can. The bearing shell provides the strength and the wear resistance.

I suspect the benefit is to the builder, not the bearing.

 

[Overland]

Around here that 7" by 6" long would be about $80 per....... CDN! so change the 30% exchange rate and its under 60 bucks usd.

Quite remarkable.
Tube 6.75 OD, 4.25 ID, 6" long is about 36 lbs; so less than US$2/lb. ?
Solid about 60 lbs, so US$1/lb. ????
Bob

 

[Overland]

FWIW, we just went through this exercise and savings from starting with tube were illusory. Go with good bar stock which you know works with your machine and tooling.

Another FWIW, a bearing housing usually doesn't benefit from more expensive stock. OEMs use cast iron where they can. The bearing shell provides the strength and the wear resistance.

It'll be welded into a frame, in Alaska. The guy is putting roller bearings in it.

I'm paying about $90 a piece for tube, delivered from Cincinnati to Greenville, SC.
Really don't want to spend hours drill out a 4" hole, 6 " long on a manual lathe.
Bob

 

[Garwood]

It'll be welded into a frame, in Alaska. The guy is putting roller bearings in it.

I'm paying about $90 a piece for tube, delivered from Cincinnati to Greenville, SC.
Really don't want to spend hours drill out a 4" hole, 6 " long on a manual lathe.
Bob

Just wondering how you are handling the flip assuming you aren't doing all the turning from one side?

I bring it up because I get the work fixing jobs like these pretty regularly when the bores don't line up.

 

[Overland]

Just wondering how you are handling the flip assuming you aren't doing all the turning from one side?

I bring it up because I get the work fixing jobs like these pretty regularly when the bores don't line up.

I have a Set-Tru chuck, so was thinking maybe face & turn OD one end on all 4 pieces, then flip, dial in, turn other OD, then maybe bore both bearing bores on this setting, with a smaller dia, in the center for the bearings to seat against.
I can probably flip end to end to do bores, once chuck is dialed in. I can face and turn OD on one end for all four pieces, then dial chuck in and grip on finished dia.
Got to hold pretty tight for bearing ID of course, but shouldn't be too difficult with a 2" dia boring bar, sharp inserts, in a 4" bore.
As always, open to suggestions.
Thanks
Bob
Bob

 

[Garwood]

Not a chance that will work. Not even remotely.

You need softjaws at a minimum or make an ID mandrel and a method to hold the tube on it.

These are the kinds of jobs that will kick your ass if you don't have the experience to do them correctly.

 

[Overland]

Not a chance that will work. Not even remotely.

You need softjaws at a minimum or make an ID mandrel and a method to hold the tube on it.

These are the kinds of jobs that will kick your ass if you don't have the experience to do them correctly.

The OD doesn't matter. The housings have some plates welded to them, and attached into a frame.
All that matters is the bearing bores, and alignment. I don't see how a mandrel will help me hold the bores.
The welding is not my concern. Customer has responsibility how he does welding.
Bob

 

[newtonsapple]

The OD doesn't matter. The housings have some plates welded to them, and attached into a frame.
All that matters is the bearing bores, and alignment. I don't see how a mandrel will help me hold the bores.
The welding is not my concern. Customer has responsibility how he does welding.
Bob

Do you think you might squish it out of round in the chuck?

The fun thing is that a 3 jaw can deform a part so that it will still measure the same id all the way around using a 2 point mic.

 

[Garwood]

The OD doesn't matter. The housings have some plates welded to them, and attached into a frame.
All that matters is the bearing bores, and alignment. I don't see how a mandrel will help me hold the bores.

Your part has two planes that must align accurately on the flip. Set Tru 3 jaw with hard jaws doesn't cut it.

Try to grasp what you're doing before you make scrap parts.

 

[Milland]

Your part has two planes that must align accurately on the flip. Set Tru 3 jaw with hard jaws doesn't cut it.

Try to grasp what you're doing before you make scrap parts.

Fair point, but sort of overwhelmed by the subsequent welding by the end user. Between thermal stresses from heating and cooling and the pulling-in against the mount plate, there's no way this will be circular to whatever degree is ideal when it's done.

I'm presuming these are for taper roller bearings, and therefore have some more tolerance for non-perfect bores. And we have to remember that the bore roundness will follow whatever errors the manual lathe's spindle bearing leave, so again, we're not talking honed angular contact spindle bearing bore results here...

 

[Garwood]

When he flips it hard jaws it'll be real likely he's off alignment 5-10 thou for the second bore.

Using soft jaws gives him assurance the flip is good, no indicating needed.

I often use an ID or od mandrel for this stuff because I don't have softjaws for my manual lathe chucks and not going to spend the money or wait a week to do a little job like this.

So I chuck on a rem with a couple hold down stud holes poked in first and turn a register and a shoulder.

So you run your first ops on all parts, then throw together a quick and ugly mandrel then you do all the 2nd ops. And you know the bores are dead nuts inline.

 

[magneticanomaly]

When I need a ring that I can't cut out of pipe, I often bend and weld the blank. Not hard (hot) with minimal tooling on an arbor press.
I agree with Garwood on the need for bores to be coaxial.
You could probably do it in one setup with a long-enough boring-bar. Bore the outboard bore, counting passes and your final cross-slide position, then repeat the sequence for the inboard bore.
Still should use soft pie jaws so they come out round, unless the finished
wall is over an inch thick

 

[Milland]

When he flips it hard jaws it'll be real likely he's off alignment 5-10 thou for the second bore.

He says he's got a Set-Tru, so dialing it back in to an established diameter isn't a big deal. Ditto he should have a registration face for perpendicularity. Let's give the OP credit for knowing how to do this.

It would be interesting to check for deformity of the first bore with the indicator at the second chucking to see if there's any OOR present, within a thou or so is fine, again presuming this gets worse after welding and mounting. If it's OK for the customer to not have the flange and facing/finish boring done at that point you sorta' have to believe him...

 

[Overland]

Do you think you might squish it out of round in the chuck?

The fun thing is that a 3 jaw can deform a part so that it will still measure the same id all the way around using a 2 point mic.

1" wall thickness ?

 

[Overland]

I appreciate the constructive comments.
As I said earlier, one option is to do both end bores on the same setting, with a 2" boring bar; as Magnet discussed.
I have a 1" wall thickness, so quite stiff material. Yes I'm sure I could deform it if I was aggressive with the chuck, but please credit it me with a little experience.

Not my design, but I'll do a good job, on my end.

Thanks Milland.

Bob

 

[Rob F.]

Something I saw on Joe Pie years ago is an easy way to keep parts parallel, use it with or without soft jaws for concentricity. Call them "bolt on soft standoffs"