Mark V Pinion broke...

[ScotSunnergren]

So this happened while working on a nice little bowl on the lathe...

broke.jpg (201.76 KiB) Viewed 1578 times

That ring was attached to what I believe is called a carriage pinion of which there are two, one on each end.

But the shopsmith.com parts seems to indicate that Shopsmith 500 Carriage Pinon 501392 is not available.

Does anyone know where I can get one...?

Thanks!

[ScotSunnergren]

There is an original full carriage assembly for the Mark V on Ebay but there is also this...

newer.jpg (83.26 KiB) Viewed 1565 times

...which says it is also for the Mark V.

Will this fit and work with my original Mark V from 1954?

[algale]

In a word, "no."

That carriage if for the 510/520/Mark 7, and the leg spacing on the main table for those models is quite a bit further apart than the leg spacing on your original Mark V from 1954. So it will not work.

[Majones1]

But you can find several 500 carriages on e-bay. Like this one which includes a photo of the part you need.

https://www.ebay.com/itm/Shopsmith-Carr ... 632-2357-0

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B8FAA896-4313-4E80-AB1F-2B287BCE0D74.jpeg (346.25 KiB) Viewed 1547 times

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55AF6E7B-294B-45BF-B1C6-3CDD623322D8.jpeg (146.69 KiB) Viewed 1547 times

[ScotSunnergren]

Thank you. Are the pinions steel or aluminum? Can they be welded?

[DLB]

Thank you. Are the pinions steel or aluminum? Can they be welded?

They are steel. Until your pics I didn't know these were separate pieces. I weld, and I would not be too optimistic about welding it by hand. But for the back one and with nothing to lose I might give it a try. Carefully evaluate what surfaces need to be flat and free of weld before trying.

From your picture and studying mine, a '57, I'm wondering if there is a change. If mine came apart I would expect it to look different than yours does. Specifically I don't understand the outside chamfer where yours failed.

- David

[ScotSunnergren]

I went ahead and ordered a full assembly from ebay but here are a couple closeups of the break fir anyone interested in the welding question. I have 0 knowledge of welding and would not know if this is doable.


Broken pinion...

PXL_20220102_175536021.jpg (135.57 KiB) Viewed 1466 times

Reference unbroken pinion...

IMG_20220102_130217.jpg (158.23 KiB) Viewed 1466 times

[ScotSunnergren]

Looks to me like the ring/washer had a chamfer to match that of the pinion body and that connection is what failed. Def looks like they are two pieces when looking at the unbroken one.

[Majones1]

Looks to me like the ring/washer had a chamfer to match that of the pinion body and that connection is what failed. Def looks like they are two pieces when looking at the unbroken one.

It does doesn’t it. Is that washer glued or welded? It looks to me like the former. But either way, this may indicate there is a greater problem because it seems like they would not put so much pressure on the washer portion of this unit that it could eventually fail. I would think that the locking pressure should only be applied to the inner chamfered portion of the unit. I would look for how it seats in the carriage and if there is excessive wear on the pinion chamfers and the carriage seats they press against.

[ScotSunnergren]

I would look for how it seats in the carriage and if there is excessive wear on the pinion chamfers and the carriage seats they press against.

No unusual wear that is obvious but it IS over 65 years old... And I cannot attest to how it was used for all but the last few months...