Gear Cutter, What can you get away with

[Larry$]

You've amassed quite a collection.
I just mostly do thing to prove I can. I also do some repair work mostly on the woodworking shop's equipment.
I passed on doing one awhile back and shouldn't have. A cast-iron bracket got broken that was part of the lift mechanism for the inside vertical head on a German made molder. It had a metric ACME type thread and I didn't have a set of taps for it. I had the machine shop down the street make a new part in steel. I told him it was metric but he didn't seem to grasp that part of it. He struggled more than I would have and had to make the part over at least twice. In the end I had to modify the part to make it work. I prefer to work in metric, easier. Our shop has a mix of domestic, Imperial, and European equipment. Sure wish the US had gone metric back in the 70s when they talked about it.

I did pick up the slotting attachment and

 

[benmychree]

Th

You've amassed quite a collection.
I just mostly do thing to prove I can. I also do some repair work mostly on the woodworking shop's equipment.
I passed on doing one awhile back and shouldn't have. A cast-iron bracket got broken that was part of the lift mechanism for the inside vertical head on a German made molder. It had a metric ACME type thread and I didn't have a set of taps for it. I had the machine shop down the street make a new part in steel. I told him it was metric but he didn't seem to grasp that part of it. He struggled more than I would have and had to make the part over at least twice. In the end I had to modify the part to make it work. I prefer to work in metric, easier. Our shop has a mix of domestic, Imperial, and European equipment. Sure wish the US had gone metric back in the 70s when they talked about it.

The metric trapezoidial thread, although similar to our acme thread is not at all the same, it has a 30 degree included angle instead of out 29 degree, it is really entirely different. a little homework on the guy's part would have saved the rework.

 

[Larry$]

A large machine shop that does a lot of work for Goodyear and other manufacturers. Given that a lot of manufacturing equipment is imported, they would have to deal with Metric on a regular basis. When his part failed after a few days we found that it has a ?pressed? brass/ bronze? threaded bushing that had slid out. I don't know if you can rely on a press fit for brass to steel or not. But in this case the fit was little more than "snug." I put two setscrews through the steel and into pockets on the bushing. Might work? The bushing has a shoulder that supports the primary load but when the shaft is reversed it still might have some load due to breakaway effort and a considerable cantilevered load.
I suspect the bushing was a purchased item. Even though I'm slow as molasses I could have gotten it done faster and not relied on a sloppy press fit.