Upper and lower output drive shafts slightly different sizes

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almackovjak
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Upper and lower output drive shafts slightly different sizes

Post by almackovjak »

Hello,
I recently acquired a 1973-1974 Shopsmith and it appears that the four splined drive hub fits only the upper output shaft of the headstock. Both shafts appear to be close to the nominal 5/8" diameter with the lower one being slightly larger preventing the hub from going on. Has anyone experienced this problem? Should I try with a new drive hub? My lower drive shaft (idler shaft?) is definitely not 1/2" as I have heard of with newer models. Any advice would be appreciated. Thank you.
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JPG
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Re: Upper and lower output drive shafts slightly different sizes

Post by JPG »

almackovjak wrote:Hello,
I recently acquired a 1973-1974 Shopsmith and it appears that the four splined drive hub fits only the upper output shaft of the headstock. Both shafts appear to be close to the nominal 5/8" diameter with the lower one being slightly larger preventing the hub from going on. Has anyone experienced this problem? Should I try with a new drive hub? My lower drive shaft (idler shaft?) is definitely not 1/2" as I have heard of with newer models. Any advice would be appreciated. Thank you.

Wheredja hear that?

I would be looking for burrs on the lower shaft.

The 5 spline hubs with a 1/2" bore are only for use with the jointer, jigsaw, scrollsaw and other SPTs witjh a 1/2" input shaft.
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Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10
E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
almackovjak
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Re: Upper and lower output drive shafts slightly different sizes

Post by almackovjak »

Thanks for your quick and helpful response. The lower shaft measures slightly larger than the upper one when measured with my cheap calipers. I get .626 for top shaft and .632 on the bottom shaft. I am trying to drive a jointer off the lower shaft. There are no burrs but some rust. Again, any thoughts on this subject would be appreciated. Thanks.
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JPG
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Re: Upper and lower output drive shafts slightly different sizes

Post by JPG »

almackovjak wrote:Thanks for your quick and helpful response. The lower shaft measures slightly larger than the upper one when measured with my cheap calipers. I get .626 for top shaft and .632 on the bottom shaft. I am trying to drive a jointer off the lower shaft. There are no burrs but some rust. Again, any thoughts on this subject would be appreciated. Thanks.
Mystery solved! Steel 'grows' as rust forms.

Gently remove all the rust. Steel wool???
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╟JPG ╢
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Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10
E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
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BuckeyeDennis
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Re: Upper and lower output drive shafts slightly different sizes

Post by BuckeyeDennis »

almackovjak wrote:Hello,
I recently acquired a 1973-1974 Shopsmith and it appears that the four splined drive hub fits only the upper output shaft of the headstock. Both shafts appear to be close to the nominal 5/8" diameter with the lower one being slightly larger preventing the hub from going on. Has anyone experienced this problem? Should I try with a new drive hub? My lower drive shaft (idler shaft?) is definitely not 1/2" as I have heard of with newer models. Any advice would be appreciated. Thank you.
Indeed I have experienced that problem. It came up toward the end of the first page of this thread, and most of the rest of the thread was spent trying to understand it.
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Re: Upper and lower output drive shafts slightly different sizes

Post by RFGuy »

I had a similar problem, albeit not with the drive hubs. When I purchased the quick index quill handle kit from Shopsmith, I found it fit easily on one side of the quill feed pinion, but not on the other. Pulled out my good calipers and checked and sure enough the diameter of the quill feed pinion is quite a bit different in diameter on the front side versus the back side. I don't remember the numbers now and would have a tough time removing one of them to measure it. I believe the manufacturing tolerances of parts inside a Mark V are a lot looser than many of us think they are...
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kenbu
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Re: Upper and lower output drive shafts slightly different sizes

Post by kenbu »

I have exactly the same issue with my 1985 510. No rust, no burs, just different shaft sizes.

Ken
DLB
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Re: Upper and lower output drive shafts slightly different sizes

Post by DLB »

In the original post, the OP said "... the four splined drive hub..." I want to emphasize the use of the singular because there are two different types of four splined headstock drive hubs, and since you bought this used you may not have both. There has been some variation in this over the years, but the upper hub is usually about 1-1/4 inch long with both ends open. The lower hub is usually about 3/4 inch long and often has one end closed. Both are near 5/8 inch ID but evidently there is some variation.

-David
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JPG
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Re: Upper and lower output drive shafts slightly different sizes

Post by JPG »

RFGuy wrote:I had a similar problem, albeit not with the drive hubs. When I purchased the quick index quill handle kit from Shopsmith, I found it fit easily on one side of the quill feed pinion, but not on the other. Pulled out my good calipers and checked and sure enough the diameter of the quill feed pinion is quite a bit different in diameter on the front side versus the back side. I don't remember the numbers now and would have a tough time removing one of them to measure it. I believe the manufacturing tolerances of parts inside a Mark V are a lot looser than many of us think they are...

An all too common event with off shore sourcing.(not all bad but...)


Made in USA and assembled in USA are not the same thing.
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╟JPG ╢
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Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10
E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
almackovjak
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Re: Upper and lower output drive shafts slightly different sizes

Post by almackovjak »

Thank you JPG, I am considering how to remove material from shaft or bore of hub. Steel wool, scotchbrite, emery cloth, ream an extra hub to fit, are good ideas but how would it be done with any degree of accuracy? It seems that I would need to take the .632" shaft down to approximately .626" which is not an insignificant amount of steel. Thanks again for your input!
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