Boring Motor Pulley for Air Compressor

[sld961]

I need a double groove 2.55" pulley with 1.125 bore to get the right rpms. The problem is that I can't find that pulley off the shelf, fixed bore or bushed bore.

I can get a 2.55" pulley with a 1" bore that is "rated" to be bored out to 1.125". I have access to a mill. Can I simply bore out the middle to 1.125" and shave the shaft key down to fit? Or do I "need" to extend the keyway groove after boring for some reason?

This seems like a simple solution, is there anything I'm missing? Any reason I shouldn't just bore out the pulley?

 

[Cole2534]

How many HP is your motor? 1/8" on the ID is only 1/16" off the key and that probably wouldn't upset me. However, if you feel it needs addressed a file and some time will get you where you need to go although a broach would be best.

Sent from my SCH-R890 using Tapatalk

 

[sld961]

How many HP is your motor? 1/8" on the ID is only 1/16" off the key and that probably wouldn't upset me. However, if you feel it needs addressed a file and some time will get you where you need to go although a broach would be best.

Sent from my SCH-R890 using Tapatalk

It's a 3 hp motor, 3450rpms. My initial thought is that 1/16" off the key won't hurt anything, but I'm no expert in this stuff, so I figured I'd ask.

 

[Cole2534]

What size is the key now?

-Cole

 

[sld961]

I don't have the pulley or key yet. I assumed it would be a standard size.

I just measured the shaft groove. It's 0.25" wide and about 0.125"deep. I assume it would be a 0.25" square key.

 

[Cole2534]

Pulling 1/16" off that wouldn't bother me at 3hp.

-Cole

 

[larry_g]

If you have the mill and not the broach then a modified key could be done. OTOH if you have to take this to a shop to have done then have the keyway in the pulley broached to keep things standard.

lg
no neat sig line

 

[sld961]

My buddy has a mill at work that he can use, so it won't be any cost for me, so I'll just shave the key a little and make it work. Thanks for your input.

 

[kkroger]

If you have the access to the mill simply use the Quill and an insert to stroke the keyway out. Pretty easy.

 

[zkling]

It will probably be fine, but why not just deepen the key way? Easily done in the lathe, bore it and then use a boring bar to slot/cut the key way.

 

[sld961]

I found a pulley that will work. There is a 2.50" pulley with 1-1/8"bore. $22 at the local Bearing and Drives Unlimited store.