Sb Fourteen-hit A Snag

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Kroll

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Guys on my SB Fourteen project I was on a good roll,everything was going smooth until today.I am posting my problem separate from my restoration project cause I just want it to be a good clean post.My problem is the bushing that is for the gear that pivots that drives the QCGB.The bore of the gear is .757 and the bushing OD is .744 and its alittle rough kinda like no oil was ever added.Bushing is part#25 and the gear is #24.Anyway I think I have couple choices:1)Is to try and make another bushing or 2)Bore the gear alittle bigger and turn the OD of the bushing down alittle so that maybe I can get one of those oil embedded sleeves and press it in.Guys it seems to me that SB should have design these parts to have a sleeve so that over time it could be replace but I'm sure there's a reason why they did not.Anyway guys I don't have much experience with these type of issues,I don't know what the gear is made of nor do I know what the bushing is made of.If its mild steel then maybe I stand a chance.I really would like to go with the oil embedded sleeve cause its alittle more forgiving than steel against steel.If you have any ideals or suggestions please let me know,cause I do know that SB parts are out of price range.Thanks krollDSC03276.JPG DSC03273.JPG DSC03274.JPG DSC03275.JPG DSC03277.JPG
 
the gear should be cast iron, with the bushing steel. If I were in your position I would ream the gear to a new ID and then make a bushing to fit. Cast iron usually runs for a long time on steel with minimal lube required because of its high carbon content. Keep us posted on progress = Jack
 
coffmajt said:
the gear should be cast iron, with the bushing steel. If I were in your position I would ream the gear to a new ID and then make a bushing to fit. Cast iron usually runs for a long time on steel with minimal lube required because of its high carbon content. Keep us posted on progress = Jack
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Sounds like good advice. If that's the worst of your problems, your golden.
 
Thanks guys,we now have a plan which leads me to ask another question be posting over in the Beginners Forum and that's about reamers???
 
Hi Kroll :)

Merry Christmas... :)

Like the others have mentioned, the gear is cast iron and the shaft is steel. This is a very good combination of materials, if properly lubricated. If you have a 4-jaw chuck on your other lathe (do you still have the Colchester ? ) you could indicate the gear true and just bore it to size, then make a new steel shaft with a nice sliding fit. If you simply try to ream the gear bore, it might not end up concentric if the hole has been wallowed out.

Brian :)
 
First bore, slightly undersize, then ream. You can bore it start to finish, but it is devilishly easy to overshoot your target bore size...

A reamer will not move a hole, only enlarge it.
 
Thanks guys for all the comments,I now understand that the combination of cast iron and steel was not one of those value engineer designs but well though out plan.I never knew that,after all this lathe and others SB lathes have lasted for yrs.Guys I posted my question about reamers over in the beginners section(I am) and receive lots of good comments so between learning about the combination of cast iron/steel and reamers how to use them so my small problem has done more good than the problem itself.Like I was told by someone "Calm seas never made a good sailor"
So something that I first though was negative has turned into something positive thanks to the membership.----kroll
Brian,yes sir I do and have a 4jaw chuck which I finish getting the head align bout month ago.But not much tooling for it yet.The bore is good though about halfway then its rough,so I may try to see if I can get the gear perfect and just take a cleanup cut then use a reamer.
 
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Hello Bob :)

I am wondering why a reamer would be a part of Kroll's situation. The way that I see it, he has a rough and bad fit between his cast iron gear and his steel shaft. If the gear is bored even slightly, it will require a new shaft turned to the new diameter. Would the reamer provide a better finished hole than boring?

No disrespect, but I would simply bore the gear to a nice and symmetric hole, and then turn a new shaft carefully, to fit the bored hole.

Brian :)
 
Yes, Brian, I misunderstood the issue. Your answer to make a new shaft was correct, or an added bushing would also work.
 
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