The Home Machinist!

I was given what they called a 5hp version of one, it was rated like a compressor motor. It had a tapered output shaft, check this one. I built it up and turned it down to fit a pressure washer pump. It wouldn't start the pump against the unloader valve. Used it for a couple of years till the magic ...

30 degrees is the standard for metric trapezoidal threads.
Ran into the same thing on my Polish made Summit lathe. Metric OD with 30 degree angle but imperial pitch for the North American market. All the other threads on the lead screw for bearing mounts were metric.

Greg

I had to make a new lead screw for the compound after a crash. I ground an 29 degree acme cutter, when I check the fit on the bent screw it didn't match. Hum. Did some research and found there was a 30 degree metric version of acme. Ground that and it matched. The new screw fit the nuts perfect.

Greg

I have a 16 x 80 lathe imported from Poland by Summit Machine Tools. It has inch pitch lead screws that are metric diameter and trapezoidal metric thread form.

Greg

Use a stepped key.

Greg

Marv is right, I have a PI tape that uses a vernier to read to 3 decimals. But it assumes the part is round and gives the average dia. The tape measures that crank into a housing are flat, ie no form to keep them straight so they will wrap around a cylinder. Think they're only divided in 1/8ths thou...

My mill uses long bolts with I think its a 10 inch riser. I have some 12 inch 1/4 wall pipe if your anywhere close.

Greg

Harolds idea is quite feasible, I made a smaller one for the variable drive on an old Delta scroll saw. Tried to post a picture but forgot how. Made it up with a plate and shaft weldament. There are two part putties that you need then cure with heat from a light bulb. High heat resistance and tough,...

You mentioned cutting the worm on a lathe. My Summit will cut 1/4 tpi, 4 inch pitch, slowest speed 20 rpm would give a carriage speed of 1 1/3 inches per second. I've never used that setting. Would you use a single point cutter or some sort of milling attachment. Square thread form is the only thing...

I agree with Harold on using HSS but I've had good results with brazed carbide cutters on large cast iron parts where the HSS would dull before finishing the face.

Greg

I dump a gallon in every few years let it sit for an hour then pump it out. If you bleed the mix into each line and let it sit you should get everything.

Greg

I produced a lot of odd parts on an 8 inch Logan. They're slow by todays standards but cheap to operate and can do some things standard machine tools can't. I added a DRO to the Logan and used it to cut 5 foot long racks for a CNC plasma table. As near as I can measure using a 24 inch dial calliper ...