Looking for "shaft coupler"

Mcmaster-Carr P/N 3084K33 Drill out the smaller bore and tap to match your shaft. The coupling shouldn't slip on the larger shaft even without a keyway.

You can try MSC, McMaster-Carr, Grainger, mebbe goggle "power transmission" supply houses. Here in Brooklyn, there is Northside Power Transmission, but a long shot for this particular part.

Easy enough to make if you have a lathe, or even better, a friend with a lathe. :) Take 1.25" solid brass or alum or steel, tap one side, drill out the other, tap yer set screws, and voila, adapter.

They might also make something in a LoveJoy type coupling, you know, with the rubber interlocking fingers. One half would fit the threaded, the other half the unthreaded. Proly sold in separate halves, precisely for mixing/matching.

Curious as to why you are gear reducing your grinder. Seems to have possibilities! :)

Aligning these things is not very easy (both to drill a very straight hole in the adaptor, as well as to tap straight, and align the motors it is all not easy.

I would just get a more matching motor. I would go the pulley route, if possible, or buy a diff. motor.

What are you going to do with this gear reducer setup? For 1/2 hp you might be able to get away with cutting a short piece of garden hose and forcing it over the 3/4" shaft and slipping it over the 1/2" shaft and using radiator hose clamps.

The correct way to couple a stationary motor with a stationary load is with a spider setup which allows for tiny misalignment and also cushions the torque slightly.

If you had a lathe you'd probably not ask these questi> I want to run a gear reducer with a bench grinder motor.The motor has a

Good advice. Altho a lovejoy coupling does cut you a lot of slack, in those regards.

As far as the OPs purpose for this, if it's more for blade sharpening, Sears sells one of these low-rpm wet wheels, about $30. Sears calls it a Utility Grinder. Got it, haven't really used it, proly my eyes were bigger than my stomach.... as usual. :) But, more importantly, it is sitting there, waiting to be used, and it looks good sitting there... :)

Get a coupler and a reducer bushing for the smaller end. You can use a bronze oilite bushing in a pinch.

Try brows> I want to run a gear reducer with a bench grinder motor.The motor has a

I once needed 2 identical couplers for different shaft sizes. I bought one coupler for one sized shaft, another for the other sized shaft. Then I pulled them both apart and reassembled as required. May not be the perfect answer for you, but no machining required!

Go to your local bearing house (Motion, Applied etc.) they can fix you up with a Lovejoy jaw type coupling (or most any other kind) with the shaft diameters you need. They stock hubs and elements separately and mix and match as you need them.

Thats why Hardinge invented 5C collets.

A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects. Lazarus Long