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Cincinnati Tray Top end gears

"Mike"

Plastic
Joined
Jun 22, 2014
Location
washington, USA
I'm putting together a 1950 10 x 24 Tray Top lathe that I bought as a basket case from the estate of a guy who started a rebuild. It came in several boxes, and I've put everything together that I have. I'm missing the two end gears, a 120t idler gear, and a smaller 66t (I think) drive gear. I do have the quadrant bracket, but not the gears, nor the shaft the larger gear rides on. I'd think I should be able to order gears from Boston gear, if I can find the specs for the original gears. I'm hoping to find someone with an early 10 or 12.5 Tray Top that could help me with some specs for these gears.

Also, I don't have the leadscrew to gearbox clutch, I'm hoping for some ideas on what I might fabricate to take it's place. The shaft exiting the gearbox is splined, the leadscrew has a typical taper pin attachment.

thanks
Mike
 
Sounds like the spindle gear is there, since it was not on your "don't have" list. Get your info from it

You are looking primarily for DIAMETRAL PITCH and secondarily for PRESSURE ANGLE

To get DP, get a good mic OD of gear, count teeth, add two to that count and divide OD into the sum

Example:

32 teeth, 2.125" OD
34 divided by 2.125 equals 16 DP

Here are two maybe helpful pubs - one shows the spindle gear in direct contact with the big idler gear

Cincinnati Lathe & Tool Co. - Publication Reprints - Tray-Top Cintilathes | VintageMachinery.org

Cincinnati Lathe & Tool Co. - Publication Reprints - Operating, Parts, and Service Manual for Tray-Top Lathe | VintageMachinery.org
 
I've sourced the end gears from a couple of other lathes. I found the larger, 120t idler gear, along with the hub and shaft from a Leblond lathe. The shaft and hub will fit up to my banjo bracket with only some minor modification. The smaller, 66t gear I sourced from a Harrison lathe. It will need a smaller diameter hub fit to the gear. So I got lucky, I'll be able to make both gears work with extremely minor mods.

Now, the next issue is my leadscrew to gearbox interface. Of course, this is also missing. I figured a simple commercially available splined coupling would do the trick, but the gearbox shaft is not a standard SAE size. So, I'll probably need to make this from scratch.
 
Proper gear timing

Mike, you say you found replacement gears from other manufacturers for use on your machine. I'd suggest you be careful with the exact diameters of these gears since these gears will set the ratios for your gear train and can affect your ability to cut threads and your actual feed speeds. To verify this the use of a thread gauge me not be enough, I would cut a couple of threads at different diameters / leads and measure the pitch on an optical comparator. Hope they work for you.
 
Gears data

I'm putting together a 1950 10 x 24 Tray Top lathe that I bought as a basket case from the estate of a guy who started a rebuild. It came in several boxes, and I've put everything together that I have. I'm missing the two end gears, a 120t idler gear, and a smaller 66t (I think) drive gear. I do have the quadrant bracket, but not the gears, nor the shaft the larger gear rides on. I'd think I should be able to order gears from Boston gear, if I can find the specs for the original gears. I'm hoping to find someone with an early 10 or 12.5 Tray Top that could help me with some specs for these gears.

Also, I don't have the leadscrew to gearbox clutch, I'm hoping for some ideas on what I might fabricate to take it's place. The shaft exiting the gearbox is splined, the leadscrew has a typical taper pin attachment.

thanks
Mike

Do you have the manual for this lathe? I have two different ones but to know which one you need I would need the serial number and year of manufacture. I would also need an email to send it to.

I have a 12.5x30 I got a while back and it has proven to be a very nice machine. What did you get for chuck(s)? I do think you can order the gears from any gear manufacturer, when I get home in a couple of days I'll try to post the width of the gears and pictures of mine.
 








 
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