WM250-VF jam up help required

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by Brian Rutherford on 09/11/2017 10:37:44:

Will put it in the lathe between centres to see if I can straighten it. Pity I can't use the cross slide to do it

That sounds as if it will put undue strain on other parts of the lathe. Better to use two V-blocks and a press. Personally I would contact Warco to see if they have a spare cross-slide leadscrew.

Russell

[Mick B1Participant @mickb1]

Posted by Brian Rutherford on 09/11/2017 10:37:44:

Pretty good bend in it at the start of the thread nearest the front. Will put it in the lathe between centres to see if I can straighten it. Pity I can't use the cross slide to do it

Depending on severity, I'd think there's a good chance you can. It's not hugely substantial.

On mine, there's a crosslide shearpin where the drive's taken from the pinion to the leadscrew. Looks like yours didn't snap like it should've. While you've got it in bits, there might be a case for judiciously weakening it as Howard suggested.

Edited By Mick B1 on 09/11/2017 10:56:32

[Brian RutherfordParticipant @brianrutherford79058]

Partially straightened it. Been ringing Warco all day for cost of replacement but no answers. Might get it good enough to let me make a replacement if warco are too dear. Have had the long lead screw out to knock shear pins out but very tight. Will drill out on the mill. Screw cutting lever is jammed so suspect other bits have sheared in the apron and fell into the bottom. Off to Belfast tonight to see son and grand kids so on hold till Tuesday.

[Ian S CParticipant @iansc]

If like mine it's 3 mm brass for the shear pin, I did the pin in very early in my learning screw cutting, I got a bit flustered and grabbed the saddle hand wheel, that stopped the saddle moving, and in a way was reassuring that the shear pin worked. On my lathe there is one (SP)on the lead screw, and one on the feed rod. There were two spare pins, and a pin punch in the tool box that came with the lathe.

Ian S C

[Brian RutherfordParticipant @brianrutherford79058]

Just an update. Got back from Ireland this afternoon so had chance for another look tonight.

Have drilled the brass shearpin out of main leadscrew. Removed the apron and managed to free the halfnut lever. Another shearpin has gone on the shaft holding the gear that drives the cross slide leadscrew.

The cross slide leadscrew i have straightened best i can but it will be tight when wound out near to its limits. Ideally it needs to be replaced. I think the pitch has been stretched. Warco want about £70 including postage and vat for a replacement so i am thinking of making another myself

[Mick B1Participant @mickb1]

You'd normally expect only one shearpin to break, and that would stop the action, so something quite complicated must've happened to break both.

I don't think I'd want to make a leadscrew myself, but that's because I prefer to concentrate on product for family and friends, and don't like to invest lots of time on tooling projects.

But as far as I can see it should be a practical proposition. If there's a way to do it (and I've not taken the crosslide off for examination), I'd try to avoid jamming on the far end of crosslide travel by having it simply run off the end of the leadscrew like my Myford Speed 10 used to rather than hitting a solid stop. And maybe use a smaller shearpin to reduce the damage from outward facing up against the handwheel bearing housing as seems to've happened to you.

[Clive HartlandParticipant @clivehartland94829]

I would suggest that brass is too hard for a shear pin and you should go back to a soft aluminium one. I have not seen a shear pin on a lathe other than an Alu one.

[Brian RutherfordParticipant @brianrutherford79058]

Lathe all back together now. Crosslide is a little tight but not patchy. Its as if the gibs are done up too tight but they are not. Still its useable. Will probably make a new one in the near future.

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