Adding a 2 groove pulley to motor shaft

Alcap said:
Would you be able to use two single pulleys side by side ? If so that might be easier to get the sizes your after
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I hadn't thought of that! Thanks. I'll look into it and see if that is a viable option. However, there might not be enough room on the shaft and it might not allow the door to close.
 
I called an electric motor place near my house and he told me that the size I'm looking for is not common in a double groove pulley because two pulleys put too much stress on a 1/2" shaft. He said it would be fine with just one pulley when I explained what I was actually going to do with it. Now that I know the original pulley was close to 2" OD maybe I can buy one (or two) of the 2" OD ones and see how it goes.

No one commented about making one. I'd like to hear your thoughts and comments on that option.
 
ARC-170 said:
I can buy one (or two) of the 2" OD ones
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The original pulley had 2 steps of different sizes, the smaller 1.93" OD and the larger 4.39" OD. If you get two pulleys the same size you will not have the same speed ranges as the original and swapping between them will be more of a problem.
 
CluelessNewB said:
The original pulley had 2 steps of different sizes, the smaller 1.93" OD and the larger 4.39" OD. If you get two pulleys the same size you will not have the same speed ranges as the original and swapping between them will be more of a problem.
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I know. I may just see about getting 2 different sizes now that I know what size to get. The plan is to have the two grooves on the motor shaft align with the 2 grooves on the driven wheel. That way, I can just have two belts; one for the small motor pulley/big pulley and one for the motor pulley/other big pulley. Changing belts is thus a matter of just taking one off and putting the other on, no need to move the motor.
 
In the original setup using a 2-step motor pulley and a 2-step countershaft pulley, the same belt fit both positions. That's probably the reason for the rather odd diameters of the 9-428 1/2" bore) and the 10-428 (5/8" bore) pulleys. Clausing still carries the 10-428 with a reducing sleeve for the older 1/2" shaft diameter motors. The factory pulley is more expensive than the Chinese single groove ones but if you consider that the total cost of doing it with two different diameter pulleys and two different length belts (assuming that you buy decent quality belts) will be doubled, And the spindle RPM's probably won't match what it should be, you aren't saving much money over doing it the original and in my opinion right way.
 
Clausing has them for about $100 shipped. Does this seem reasonable?

However, I have some hesitation. When I was measuring the speeds I currently have, it vibrated quite a bit at the higher RPM. The machine is bolted securely to the table and the table is sturdy. Is this normal? I haven't really needed the higher RPM's yet, so getting a pulley that allows for 2,000 RPM on a machine that vibrates gives me pause. Would it help to take some video so you can hear and see it?
 
1) How old and crunchy is your belt? (very common problem)
2) Is your motor shaft straight? (bent shafts on 1/2" shaft motors are unfortunately common also)
3) How about your motor pulley? Is it a low budget unbalanced diecast part? (again not uncommon)

$100 seems like a lot but reproduction and used parts also go for big money on ePay. (It may be your best option)

Definitely check your motor shaft before you spend the money on a 1/2" bore pulley.
 
CluelessNewB said:
1) How old and crunchy is your belt? (very common problem)
2) Is your motor shaft straight? (bent shafts on 1/2" shaft motors are unfortunately common also)
3) How about your motor pulley? Is it a low budget unbalanced diecast part? (again not uncommon)

$100 seems like a lot but reproduction and used parts also go for big money on ePay. (It may be your best option)

Definitely check your motor shaft before you spend the money on a 1/2" bore pulley.
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1. It's a new link belt. Maybe it's too loose?
2. I put a dial indicator on it and it was perfectly straight.
3. Yes, it appears to be diecast.

Well, I looked at the set up again and it runs fine. I wonder if I had something out of place when I tried this before? I posted a video of the machine running:
 
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In my humble and not very knowledgeable opinion not having the exact same speeds as original won't make a bit of difference in the operation of your lathe. You are going to find speeds and feeds that work for you with whatever pulleys you have on your lathe. 2" and 4" pulleys are so close to original that you will never see any difference. The difference between a 1.93" pulley and a 2" pulley 3.5% faster. Your 15 rpm will now be 15.5 rpm The difference between a 4" pulley and a 4.39" pulley is 9% slower. The fast speed on my Craftsman 12x36 is 2072 rpm. With a 4" pulley it would be 1885 rpm. Still not enough difference to make any difference in the operation of your lathe.

You can find 2" and 4" pulleys with a 1/2" bore all over the place. You can probably find a 2"/4" step pulley too. Surplus Center has 1.75 and 4.45 1/2" bore pulleys. McMaster Carr and Grainger have them too.
 
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