Welding a plain bearing

[Sonic EscapeParticipant @sonicescape38234]

I want to make two plain bearings. And some kind of locking ring. They will rotate only 90°, from time to time. So friction is not an issue. Since I don't have how to make a pillow block I want to weld the bearing directly. Welding will modify it's internal diameter? I can't turn it on the lathe to fix it after it is welded.

[Sonic EscapeParticipant @sonicescape38234]

[bernard towersParticipant @bernardtowers37738]

You could make a hone to use after welding.

[Sonic EscapeParticipant @sonicescape38234]

What is a hone? Some kind of reamer?

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Sonic Escape, Cylinder Hone

Regards Nick.

[Ady1Participant @ady1]

If you spot weld it in as far from the bore as possible would it be ok?

Less heat= less distortion issues

Use a high setting, in…get a bead…out

A lower start voltage gives you a more focussed arc if memory serves

[Howard LewisParticipant @howardlewis46836]

Welding is likely tom produce some distortion, if only because of the concentrated area heated to melting point.

(Presumablt a steel bush welded to some form of steel body? &nbsp

So if possible, ream as a last op.

A reamer will probably remove any high spots more quickly than a hone.

Howard

[bernard towersParticipant @bernardtowers37738]

Just thinking that not everyone has a 20mm reamer, you can make a hone or a lap.

[Gary WoodingParticipant @garywooding25363]

I'm being thick here. On your diagram I don't know what you want to weld to what.

[Brian WoodParticipant @brianwood45127]

Not thick at all Gary, I don't know either.

Brian

[not done it yetParticipant @notdoneityet]

Posted by Brian Wood on 30/05/2023 17:59:47:

Not thick at all Gary, I don't know either.

Brian

Nor me – and likely many others. If we had dims of housing etc, I might suggest welding in something that can be machined as a bearing housing – then fit the shaft and bearings?

Thoughts on stainless steel against steel? Not my favourite, for sure.

[Howard LewisParticipant @howardlewis46836]

Not enoughn information for us to really nhelp, only to guess.

IF the part with the M3 thread is to be welded to the 50mm long part, there may be no need to weld. The parts look substantial enough to drill and tap through so that they could be fastened together with screws.

But how will the two parts be restrained / located / rotated ?

Tell us more and we may be able to help you!

Howard

[Sonic EscapeParticipant @sonicescape38234]

The thing should work like a hinge. I want to make a chop saw for cutting metals with a carbide blades. It is a long story, first I was thinking on a table saw, then a band saw and finally I choose this.

Red and green are the parts connected by the hinge. One is the base of the saw and the other is the part that holds the motor + blade. Blue is the stainless steel bar. And with yellow are the parts that should fit close over the blue bar. The small yellow parts at both end should hold the bar in place with a set screw. The length of the bar is 50cm.

Now I realized that I could never weld the yellow parts aligned without the blue rod in place. And the rod will get stuck if welding deforms the parts. So a reamer/hone would not help here. The only solution that I could think now is to weld the yellow parts on small plates, but it is becoming to complex.

Edited By Sonic Escape on 30/05/2023 21:12:13

[bernard towersParticipant @bernardtowers37738]

Tack parts in place the remove rod and finish weld.

[Sonic EscapeParticipant @sonicescape38234]

Posted by bernard towers on 30/05/2023 21:19:29:

Tack parts in place the remove rod and finish weld.

How? I was never able to tack parts precisely while welding. The dilatation force is very strong. Here is even more difficult, aligning two cylinders half a meter apart.

Edited By Sonic Escape on 30/05/2023 21:42:07

[Nigel Graham 2Participant @nigelgraham2]

I think you'd be better with mechanical fixing methods if at all possible, rather than trying to weld it, especially with mixed alloys.

The slightest distortion will have a large effect over a span of >500mm.

Make the hinges as cylinders welded independently to small plates that can be bolted to the frames, so you can align them by adjusting them on the bolts.

[Nicholas FarrParticipant @nicholasfarr14254]

Posted by Sonic Escape on 30/05/2023 21:41:45:

Posted by bernard towers on 30/05/2023 21:19:29:

Tack parts in place the remove rod and finish weld.

How? I was never able to tack parts precisely while welding. The dilatation force is very strong. Here is even more difficult, aligning two cylinders half a meter apart.

Edited By Sonic Escape on 30/05/2023 21:42:07

Hi Sonic Escape, it is quite a normal way of doing such things. Put your two yellow parts that are to be welded to the red part, onto your blue bar, and then hold them in position on the red part aligned up correctly, and then put three or four small tacks on each, then slide your other yellow parts on the blue bar, and hold the green part in alinement, and then tack them in three or four places. Keep all your tacks in the same pattern though, then when you are satisfied, remove the blue bar and weld the parts up, in the same sequence, so that any distortion is the same as possible for each piece. You will probably have to do a bit of easing out once welded and cooled, to get your bar to fit nicely.

Regards Nick.

[noel shelleyParticipant @noelshelley55608]

Hi Sonic, I would be VERY cautious of using stainless as the pin ! The more so in this application with swarf Etc about. Stainless is notorious for picking up, even a small rotation may cause it, even lubrication may not stop it. As for alignment, use an adjustable reamer to get your size right.after welding. Good luck. Noel.

[Sonic EscapeParticipant @sonicescape38234]

Posted by noel shelley on 30/05/2023 22:30:43:

Hi Sonic, I would be VERY cautious of using stainless as the pin ! The more so in this application with swarf Etc about. Stainless is notorious for picking up, even a small rotation may cause it, even lubrication may not stop it. As for alignment, use an adjustable reamer to get your size right.after welding. Good luck. Noel.

What you mean by picking up? I have no special reason to use stainless steel. It's just the most abundant material I have.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Sonic Escape, Noel is talking about galling, which S/Steel is often prone to do on rotating parts.

Regards Nick.

[Ady1Participant @ady1]

Stainless is tough but quite malleable compared to many metals, so it's prone to deformation under load

Fabulous for bending 90 degrees and maintaining its strength

You MAY have a higher spec stainless steel, like they use for yachting fixtures, only way to find out is to give it a whirl and see what happens

[Paul LousickParticipant @paullousick59116]

Machine the bore of the bush to finished size and use Loctite to fix the bush into its housing. (Crankshafts on model engines use Loctite for fixing the cranks to the shaft)

[HopperParticipant @hopper]

You don't need bronze bushes in such an application. Steel on steel would work just fine for a home use chop saw hinge. I would make the pivot blocks from square mild steel and bolt them in position to allow for final adjustment so you can set the saw up to cut dead square in all planes and to make sure the cutting disc is spot-on vertical. If you weld it all up you will be stuck with whatever alignment you weld it at.

Edited By Hopper on 31/05/2023 00:58:21

[Tim StevensParticipant @timstevens64731]

Your drawing shows – from the left, a short tube fixed to the shaft, a rotating tube, a second rotaing tube, then a space, then the same, reversed.

I don't see why you need two tubes at both ends. Can I suggest that you make a double-length tube for each end, separate them by a long, thin tube between them, and hold the whole thing together with your short tubes? Only the short end tubes are fixed. But make the short tubes bigger so they wont slide into the sleeve at each end. No welding required, and each bearing set can turn on the inner or outer diameter depending on which offers the less friction.

And – in 50 years when it gets a bit worn, it all comes apart easily so your great-grandchlidren can restore it.

cheers, Tim

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