I have been needing a thread dial for my South Bend 9 inch lathe. There are reproduction units of high quality available to buy for around $120 with shipping. This is a reasonable amount but right now I just can't afford it , so I decided to make one to do until I can purchase one.
The big problem was the gear. I could not find one anywhere, so I tried to make one using some redneck hobbing method I saw on the internet. Well, it didn't work. After screwing up three gear blanks I gave up. Then while surfing eBay, I found a nylon gear real close to the correct diameter and it had 32 teeth. They came from China and cost $5 for five gears. I figured it was worth a shot. they arrived a few days ago and are a regular spur gear. The teeth meshed with the lead screw but not as well as I wanted. I ground a piece of 1/4" square tool steel to fit the acme thread on the lead screw and held it in my hand and scraped the nylon gear teeth by hand. It only took about 15 minutes and it fit a whole bunch better.
I started with a piece of aluminum 1 1/2" in diameter and 3 1/2" long. I milled and drilled till I had the body made.
A piece of 1/4" drill rod made the shaft.
A small piece of brass made the number dial. I cut a strip of paper equal to the circumference of my chuck and folded it 4 times to divide it into 8 equal divisions. I put it around the chuck and used a pointer and this allowed me to index to position and scribe the lines on the brass number dial I made.
I drilled a 5/16" hole through the dial body at a 3 to 4 degree angle to tilt the dial when mounted. This let the gear mesh much better. the mounting rod was machined to .314" for a press fit into the body. It won't move, in fact it would mess up the body if I tried to get it back out. You can see this angle in the photos. It is slight so it presents no problem.
This was a simple project that took about 3 hours to make and works so well, I don't have to hurry to buy an expensive rpro unit. I am putting all the photos at the end here along with the print. (there are two copies because the picture quality is kind of poor.)
The big problem was the gear. I could not find one anywhere, so I tried to make one using some redneck hobbing method I saw on the internet. Well, it didn't work. After screwing up three gear blanks I gave up. Then while surfing eBay, I found a nylon gear real close to the correct diameter and it had 32 teeth. They came from China and cost $5 for five gears. I figured it was worth a shot. they arrived a few days ago and are a regular spur gear. The teeth meshed with the lead screw but not as well as I wanted. I ground a piece of 1/4" square tool steel to fit the acme thread on the lead screw and held it in my hand and scraped the nylon gear teeth by hand. It only took about 15 minutes and it fit a whole bunch better.
I started with a piece of aluminum 1 1/2" in diameter and 3 1/2" long. I milled and drilled till I had the body made.
A piece of 1/4" drill rod made the shaft.
A small piece of brass made the number dial. I cut a strip of paper equal to the circumference of my chuck and folded it 4 times to divide it into 8 equal divisions. I put it around the chuck and used a pointer and this allowed me to index to position and scribe the lines on the brass number dial I made.
I drilled a 5/16" hole through the dial body at a 3 to 4 degree angle to tilt the dial when mounted. This let the gear mesh much better. the mounting rod was machined to .314" for a press fit into the body. It won't move, in fact it would mess up the body if I tried to get it back out. You can see this angle in the photos. It is slight so it presents no problem.
This was a simple project that took about 3 hours to make and works so well, I don't have to hurry to buy an expensive rpro unit. I am putting all the photos at the end here along with the print. (there are two copies because the picture quality is kind of poor.)