Odd acme thread for carriage feed nut

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Eaglewood

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Hi I am a newbie to this site and have recently transitioned from a toolmaker ( retired) to a hobby machinist.
I have been refurbishing a Maximat Standard and adding a taper attachment but the feed nut needs attention and it is a 15/32-10 am me thread. I could at last resort single point it but don't like doing that an such a small bore. Any suggestions on finding a tap??
Will post pics off tapper attachment when I decide on a proper finish.
Thanks
 
Eaglewood said:
Hi I am a newbie to this site and have recently transitioned from a toolmaker ( retired) to a hobby machinist.
I have been refurbishing a Maximat Standard and adding a taper attachment but the feed nut needs attention and it is a 15/32-10 am me thread. I could at last resort single point it but don't like doing that an such a small bore. Any suggestions on finding a tap??
Will post pics off tapper attachment when I decide on a proper finish.
Thanks
Click to expand...
Most Likely a 1/2 x 10 acme tap
Is the shaft Dia. 15/32
 
Littlemachineshop had a nice acme thread gauge for sale a couple of weeks ago. It has many different acme thread sizes cut into the gauge. I bought one to measure some unknown threads on some ancient shafting I picked up from an estate sale. but haven't used it yet. Might be handy to try out one of these gauges?

Glenn
 
15/32" is .4687" 12 MM is .472"
10 TPI is .1" thread lead or 2.54 MM (.0984")
Use a thread pitch gauge and measure the lead.
 
Thanks guys. Some interesting food for thought. The metric attack is very close. The lathe could be had with either a metric or inch screw , mine is inch. The shaft measures .468. I wonder if the .0016 pitch difference will be an issue?
Thanks again
Dick
 
Eaglewood said:
Thanks guys. Some interesting food for thought. The metric attack is very close. The lathe could be had with either a metric or inch screw , mine is inch. The shaft measures .468. I wonder if the .0016 pitch difference will be an issue?
Thanks again
Dick
Click to expand...
On a ten pitch Acme thread, you have a OD tolerance of 0.005". So it could actually be a metric OD of 16mm. I would not rule it out for that brand of lathe made over in Eastern Europe. Now, be careful, the flank angle is more than likely 15 degrees for a total included angle of 30 degrees. This fits in more in line with the European standards or ISO.

Since you are doing some rebuilding, there is no reason to follow what was there originally. Change it to a 1/2-10 ACME left hand thread.

Ken
 
Hi Ken, why a left hand thread? And you are right, the flank angle may be different because of it's Austrian birth.
Probably need to change to 1/2-10 everything.
Dick
 
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