9" SM Utilathe Restoration

[RobinHood]

Turn her down to 1/2" sound ok?

I would turn it down just enough to clean up. Nice and parallel. You can indicate off of the bearing journals to see if the centres in the shaft are good to use. They should be, unless someone in the past has beat on them with a hammer. Then it gets a bit trickier, but still doable.

The pulley that was on that shaft probably has some deep gouges in its bore. I would bore it over size and make a custom sleeve that fits the undersized motor shaft and the oversized pulley bore. A piece of heavy walled DOM pipe would be a good starting point for a sleeve. I would make the sleeve a light press fit (with some red locktite) into the pulley. If the pulley is aluminum, you can even go the shrink fit route: leave the sleeve OD oversized. Heat the pulley evenly with a propane torch (or heat gun) and use red locktite and drop it in. Once it cools, it won’t come out again.
Then bore it out so the shaft just fits with no play. Cut the key way into the sleeve where the pulley’s is and install.

 

[YYCHM]

You can indicate off of the bearing journals to see if the centres in the shaft are good to use.

Oh great, now you tell me In any event, I checked it's all good, turning true. I'll take it down to 0.55 and call it quits, I'm at 0.56 now. Does the pulley sleeve need to be steel or can it be anything i.e. aluminum?

 

[RobinHood]

Oh no, don’t stop, if you are doing well and you are happy, go for 1/2” shaft diameter. Just more work for you...

I aluminum would work. Make it a good fit to the shaft - ie no slop - or it will have a tendency to wobble and come undone and you will be back to square one when the shaft/bore gouges.

 

[YYCHM]

You sure you measured the ID correctly? Maybe measure the shaft‘s bearing journal instead?

Based on the OD, it looks like a quality 6203-2RS deep groove ball bearing would work.

6203 - 2RS is 40mmm OD, 17mm ID and a width of 12mm

https://www.skf.com/au/products/rol...ings/deep-groove-ball-bearings/productid-6203

PA has some cheap ones - not my first choice; would do in a pinch, however. I’d go for SKF Explorer (not their cheap line), NTN, NACHI, ore something along those lines.

https://www.princessauto.com/en/detail/bearing-6203-2rs/A-p3850658e

I went to SKF this morning. Doesn't appear to be a place that deals with general public purchases. Looked to be an engineering office. To gain access you had to call someone to come screen you with a thermometer. I didn't pursue it other than to read all the instructions to gain access.

Who in Calgary sells bearings over the counter other than PA?

 

[Dabbler]

Transmission supply, Acklands both deal with SKF. SKF and FAG both have technical suppport lines, and will get you to the exact bearing number, which you can then order from the distributor.

 

[Johnwa]

I’ve got some from Motion Canada . I think they bought BC Bearings.

 

[RobinHood]

Also Gregg Distributors.

https://www.greggdistributors.ca/catalogue.php

 

[YYCHM]

Has anyone used BDI? It's close to MSM which I need to visit.

 

[RobinHood]

Not yet, been meaning to. Drive past them often enough...

if they sell quality brand bearings - you are good to go.

 

[YYCHM]

Trying to set this pully up to over-bore it. I have it dialed in radially but I'm seeing 0.04 axially. What's acceptable?

 

[RobinHood]

You put shims in behind the pulley where it butts up against the chuck jaws. Then check radial runout again -> set to zero (by moving the independent jaws). Check axial again -> set to zero (by shimming). Back and forth until it runs as true as possible in both axis.



speaking of shims: you should put some aluminum or copper pieces between the jaws and the pulley so it does not get chewed up by the hard jaws.

 

[YYCHM]

Not yet, been meaning to. Drive past them often enough...

if they sell quality brand bearings - you are good to go.

Looks like BDI is a pretty good place for bearings. They carry SKF and other brand names bearings and Leeson motors etc. BTB- The SKF office in Calgary is a design office, they don't sell to the general public (BDI confirmed that).

Now here is the deal......



The guy at BDI measured up my bearings and came back out with two to choose from and said..... these ones you can have or you can pay for these ones Not to be one to look a gift horse in the mouth I took the freebie's LOL.

Look to be labeled 6203 ZZ C3 on the outer race and 6203Z on the inner race.

 

[YYCHM]

Done and Done.....



Got the motor bearings swapped out and the old defunct pulley sleeved from 5/8" to 1/2". She is running, quieter and smoother than before, and the pulley appears to be turning true in both axis and has no slop fit wise. Won't know what sort of improvement was achieved until I remount it on the lathe again.

Interesting that my camera captured this image while it was running. The image makes it looks like it's stopped? Look at the fwd/stop/rev switch, it's running.

 

[RobinHood]

Good job, Craig.

 

[YYCHM]

Good job, Craig.

Thanks.

The sleeve turned into a bit of a Bubba job I think. I drilled the defunct pulley from 5/8' to 11/16' on the lathe and then turned an aluminium plug until it just about fit the pulley bore. I had to hammer the plug into the pulley it was that tight. I then drilled the plug while mounted in the pulley on the lathe to 1/2" and started test fitting the rotor shaft. 1/2" drilled didn't have enough wiggle room for the 0.505" rotor shaft, so I started boring the 1/2" hole in the mounted pulley plug. Once satisfied I was close, I cut the plug length wise using a manual jigsaw where it intersected the pulley keyway. This allowed the plug to be backed out of the pulley bore. I then milled the saw cut along the plug to 3/16" to accept a key (or so I thought). With the plug re-installed in the pulley I found it wouldn't accept a 3/16" key so lots of filling ensued (LOTS). When I finally had the keyway sorted out (and more than filling was resorted to), I cleaned everything and red Loctite' d the sleeve into the pulley. Now test fitting the pulley to the rotor shaft revealed it would go on 3/4 and then get too snug to go any further with out resorting to a hammer. I need to get that pulley on/off without resorting to a hammer and puller every time. Hmmmm…. have some sort of pulley bore taper going here as the rotor shaft measures spot on along it's length. Now what to do? Boring didn't prevent this? Well... out comes the valve grinding compound and a few turns later that pulley was fully seated. A few more applications of valve grinding compound and I could mount and dismount the pulley no problem.

So, ya... Bubba' d my way through this LOL.

 

[RobinHood]

Nothing wrong with “Bubba’ing“ if the end result is what you wanted. You used the tools at hand and with some ingenuity got the job done.

It was probably the locktite that stoped the sleeved pulley to fit after you “glued” it. In oder for the locktite to work, it has to take up some room between the parts to be glued. It’s not much, but is is there. That’s the amount you had to take out with valve grinding compound.

 

[YYCHM]

Well, I won't be afraid of tackling bearings now. They just tapped on easy-peasy. Re-assembling the motor was a bit of a head scratcher. The rear bearing caps need to be captured in order to align with the front caps so that you can get the retaining screws in. I was getting pretty flustered until I noticed that the long rods that retain the cage end covers just happen to be the same size and thread. You can use those to capture the back caps then slide the front caps down the long rods into place and then install the retaining screws one at a time

 

[Tom O]

Nice I’d be tempted to remove the stickout of the keyway for safety sake.

 

[YYCHM]

Nice I’d be tempted to remove the stickout of the keyway for safety sake.

Yup, going to do that for sure.

 

[YYCHM]

Well...… this is a little disappointing

I remounted the re-built 3/4 HP motor on the lathe and the vibration is still there. It's a little less and running quieter but it's there and not as smooth as running the 1/2 HP motor?

Dunno now.