View Full Version : Hybrid arbor-pulley

brian Rupnow
05-16-2018, 01:06 PM
I have a 1/2 horsepower 1750 rpm motor on my main workbench out in the garage that is primarily used to "run in" small engines to loosen them up. I want an arbor to mount my different polishing buffs on. I don't like polishing in my lathe because it makes such a mess. I don't want to be constantly changing the pulley for a shaft mounted arbor because it gnarls up the motor shaft. LIGHTBUULB!!!--Make a threaded arbor that has the pulley permanently mounted to it.

05-16-2018, 01:23 PM
I would not want a spinning pulley next to my buffs. I have a dedicated polish motor with the extended reach housing. Even it gets in the way sometimes. I can't imagine a spinning pulley would be very safe. But you're not me. :cool:

Dave C
05-16-2018, 01:44 PM
Get yourself another motor to mount your buffs on. It will be a lot cheaper than the doctor bill you will have after catching a finger under that V belt.

05-16-2018, 02:01 PM
Get yourself another motor to mount your buffs on. It will be a lot cheaper than the doctor bill you will have after catching a finger under that V belt.
Or against the edge of the pulley. I've got a scar on my right index finger from getting too close to the edge of a running pulley. (Setting the timing on a running car, not polishing.) I'm glad it wasn't under a belt. My hand would have gone one way and the finger another. :eek:

05-16-2018, 03:01 PM
If I'm understanding Brian's thoughts, the pulley would only be used for the breakin of new engines, at which time he wouldn't be buffing anything. And conversely, when he's buffing the motor isn't turning anything with the pulley, it's just a smooth free wheeling part next to the buff. Sounds okay to me. The new arbor is cantilevered out there a ways, but then he's an engineer and can assess that for himself.

brian Rupnow
05-16-2018, 04:36 PM
Prior to building this thing I ran my buffs in the lathe at about 500 rpm. This should be a big improvement at 1750 rpm. I won't have buffs on there when I'm using the v-pulley to break in an engine. Conversely, I won't have the v-belt on there when I am buffing something. Think about it--For the last 8 years I've been spinning those buffs about 2" from the spinning jaws on the lathe chuck, with a half inch bolt and nut making my arbor. This was a nice little project, based 40% on need and 60% to give me somethin g to do this afternoon.

05-16-2018, 05:20 PM
Interesting old looking bench grinder in the rear of the first photo.

05-16-2018, 05:55 PM
Suit yourself. The pulley is spinning when the motor runs. It doesn't have to have a belt on it to be dangerous.. :cool:

brian Rupnow
05-16-2018, 06:50 PM
Interesting old looking bench grinder in the rear of the first photo.
Good eye, Sasquatch. My dad bought that from the blacksmith in Bancroft when he closed up shop when I was a kid. I have no idea how old it is, but it's probably older than I am.

05-16-2018, 08:42 PM
I don't under stand wy you dont,
A put a soft pad made from copper brass or alum, between setscrew and shaft.
B slide a close fitting cover over pulley when not in use..

05-16-2018, 11:29 PM
Brian - How does the motor shaft actually drive the arbor? I don't see a key or setscrew anywhere. But I do see and allen wrench so there must be a setscrew somewhere.

brian Rupnow
05-17-2018, 09:16 AM
One 1/4"-20 set screw thru the 1 1/4" sleeve and seated in the bottom of the keyway. The pulley is not welded either--it has a 5/16" set screw thru the hub area and bears against the outside of the 1 1/4' diameter piece. I didn't want to make too many things "immovable" in case anything actually did give me a problem.

05-17-2018, 12:12 PM
The setup and manner of use seem just fine to me. With no belt on the pulley during buffing at worse you will touch the edge of the pulley and scuff a bit of skin. Then you won't do that anymore.

It would never pass muster in this safety focused age in a multi person shop but as you say it's still head and shoulders better than what you did before.

It would be different if it were going to have a belt in the pulley during buffing. Then I'd be siding with the doomsayers. But without a belt in place it's no worse for safety than any number of other power tools we all use and a lot better than many of them.

Dave C
05-17-2018, 01:09 PM
Didn't intend to be a doomsayer, but like ccwken I speak from experience. I have a scar under one fingernail that has been there since 1954; the result of getting the fingertip under the v belt on a jig saw. Mom nearly fainted when she saw the nail had been pulled out from the rear and still attached at the front.

05-17-2018, 02:52 PM
Yeah, but there won't be a belt in place when he's buffing. The pulley is only being used for short times to break in a new engine.

05-17-2018, 08:13 PM
Yeah, but there won't be a belt in place when he's buffing. The pulley is only being used for short times to break in a new engine.
So you're saying the pulley doesn't spin when he's buffing? See post #8

brian Rupnow
05-17-2018, 08:37 PM
I don't polish a lot of things. During my fourty year fascination with hot-rods, I polished a number of aluminum brackets and small parts, to the point where I actually became quite good at it. I "studied" the art of polishing, read everything I could find on the subject, and like many other "new" things I learned, I flogged it right to death. Eventually the hot-rods left my life, and I took up machining as a hobby. Somewhere along the way, I lost track of my dedicated arbor for polishing buffs, and resorted to a long bolt with a nut and two washers holding the buff, with the shank of the bolt held in the 3 jaw chuck on my lathe. If you think the picture I posted is terribly dangerous, you would have had a heart attack if you knew how many times I got my knuckles rapped by a spinning chuck jaw. I decided to polish the last engine I built, and while doing it, decided that I really needed to do something "a little better". I only have one other motor that is not "fully dedicated" and that is the one I added the arbor to. I don't do enough polishing to drop $100 on another motor, so will live happily with what I now have, knowing full well that every time I use it I am courting death and dismemberment. When my fingers go flying off into the sunset without the rest of me, I will fondly remember all of the warnings I have received on the forum--Brian

brian Rupnow
05-19-2018, 09:48 AM
Not out of any undue considerations of my fingers, but in order to get the correct ratio I machined a smaller v-pulley from aluminum and mounted it on my arbour. The original pulley which I showed on the arbour was 3.5" diameter. The new one is 2 1/2" diameter, which restores the ratio I wanted and does get the pulley a little farther away from my fingers if I want to polish something on the buff.

Dave C
05-27-2018, 01:57 PM
Did some web searching and found this pic of the saw that pulled my fingernail off. Notice there is no belt guard mentioned. Sorry but could not find an English version.


05-27-2018, 02:45 PM
If you ever have to replace the bearing heads on your mower deck, inside the old one/s is a flanged shaft.
It is of machinable steel so the flange end can be re-purposed to hold a buffer etc, or in my case, a slitting saw.
Added bonus of this one is that the spline is a multiple of 3 so it grips positively in a 3 jaw