need a gear made

I don't claim to be an expert on gears. I design medical devices and fixturing and often use gearing in my designs so I have some practical experience using them.

A 16 tooth spur gear with 72 teeth has a PD that is 4.5" and an OD that is 4.625"

73 teeth does not make sense. I have owned several old lathes and I don't see how the correct feed ratios can be obtained with a 73 tooth gear in the feed gear train.

Charlie
 
CharlieW said:
I don't claim to be an expert on gears. I design medical devices and fixturing and often use gearing in my designs so I have some practical experience using them.

A 16 tooth spur gear with 72 teeth has a PD that is 4.5" and an OD that is 4.625"

73 teeth does not make sense. I have owned several old lathes and I don't see how the correct feed ratios can be obtained with a 73 tooth gear in the feed gear train.

Charlie
Click to expand...
well the only thing i know about gears is if you get your finger between them you have one less finger. i have not threaded with this lathe yet so i dont know, ive counted this gear 3 times my wife counted 2 times my son counted 1 time we all came up with 73 teeth, why this is i dont know, but while watching this machine run it looks like it was made for it, i did talk with the guy that still has most of the books for sheldon lathe company and he worked for them 40+ years but he did not have the manual on my lathe, and he said since that gear fits on a stud and has no slot to adjust it a 72 may not fit it. now some where in its life maybe somebody switched it out and did not know what they were doing, i dont know, so i'm kinda stuck, i dont know if i need to count all three gears on on the banjo to come up with a solution to this:thinking: the gearbox gear is 96 teeth
 
It certainly has 72 teeth + one missing makes 73. I use to have a Sheldon like yours but it didn't have any gear issues so I have no idea what gearing it had.

I went out to my shop and went through my old manuals and came across manuals for Sheldon 10", 11" and 12" lathes.

I think this information may be helpful.

EndGearing_w.jpg
QC-Box_w.jpg

Charlie

The 2 pages show Sheldon gear numbers. I noticed that the picture showing the end gear train shows a gear number listed. Does the one with the broken tooth have a "K" number on it? Based on the numbers listed, I suspect the broken gear does not belong to the lathe.

EndGearing_w.jpg

QC-Box_w.jpg

EndGearing_w.jpg

QC-Box_w.jpg
 
CharlieW said:
It certainly has 72 teeth + one missing makes 73. I use to have a Sheldon like yours but it didn't have any gear issues so I have no idea what gearing it had.

I went out to my shop and went through my old manuals and came across manuals for Sheldon 10", 11" and 12" lathes.

I think this information may be helpful.

EndGearing_w.jpg
QC-Box_w.jpg

Charlie

The 2 pages show Sheldon gear numbers. I noticed that the picture showing the end gear train shows a gear number listed. Does the one with the broken tooth have a "K" number on it? Based on the numbers listed, I suspect the broken gear does not belong to the lathe.
Click to expand...
the number on the gear is a m758 and i do have the manual you have too

EndGearing_w.jpg

QC-Box_w.jpg

EndGearing_w.jpg

QC-Box_w.jpg
 
the manual calls for a 64 tooth but can a 64 tooth be made with that diam, i dont know:thinking:
 
ok im going to get some 7018 rods and fix it but i do want to get one made cause i dont want any down time at a later date:biggrin:
 
You must log in or register to reply here.
Back
Top