Building the Shopnots thickness sander....problem with pillow block bearings.

[betacrash]

Anyone here experienced with pillow block bearing? I am doing the final assembly on my shopnotes thickness sander and I am stuck because my 5/8" axle for the drum will not fit into my 5/8" bearing. I used some sandpaper and cleaned off the axle really good (still a no go). Are they supposed to be hammered on? Even if they are it seems to be an insanely tight squeeze. Any suggestions would be appreciated. thanks.

[cgallery]

I doubt it will help much, but try freezing the rod. This will reduce its diameter very slightly.

[LCHIEN]

they should be a tight fit because you don't want the axle rotating in the bearing, you want the bearing to be turning with the axle.

I wouldn't pound it in, light taps with a small rubber mallet, maybe. Don't want to damage the bearing.

[bmyers]

It was a bit of a challenge to get them on the shaft. A little extra "polishing" on the sleeve ends of the bearing will give some wiggle room and help things line up. Freezing the bar can help too, I didn't do that.

You don't want to hammer them on there so much as "tap" them into place. Don't tap them too far, it's easy to go past where you need them. Keep checking the placement while tapping until it's home..

I had to really polish up the bearing and shaft until they fit together. Also if it starts to go in slightly crooked it doesn't fit at all.

Any tapping or you do should be done to the inside sleeve of the bearing not the outside/case of the bearing. This will damage it.

IIRC, I placed the bearing on the floor (after a whole bunch of polishing) so the the inside sleeve of the bearing was on a block of wood. Stood up and tapped on the rod with a hammer and a pine wood block on the shaft. Once it was flush with the bearing I flipped it over and used a deep socket to rest against the sleeve of the bearing again and tapped it the rest of the way on. The pulley side needs to go a little farther than the other side but it should be easier going at that point.

Hope this helps. It wasn't easy and took more time than I thought it would.

You can see that one I made in various stages:

http://billswood.blogspot.com

Bill

[TheRic]

If the end of the rod is flat, squared off. You might want to consider putting a slight bevel on the end of the rod.

As Cgallery said getting the rod cold to shrink it slightly might help. Also make the bearing warm to enlarge the hole slightly. Maybe put it in the oven at 100 F. The bearing should be ablel to handle that, since a shop might get that hot.

Between the two it might help with things, don't think it could hurt.

[bmyers]

Oh yeah, I forgot to mention that bevel on the ends of the rod. Not much, just a little to get it started..


Bill

[betacrash]

bill, its great to see someone else building one. Im not hooking mine up to a table saw, i bought a standalone motor to power it. I really think the conveyor is a cool idea but Im getting burned out on making it and I feel like just putting a melamine table on it and push the stuff through. I finished gluing up my conveyor last night so today I will see if it was worth it.

[LCHIEN]

good points made:
1) bevel the end of the rod very slightly.
2) support the inner bearing race with a small sylinder-shaped object (like a deep socket) to tap the bearing on or ptap the rod into the bearing.
3) For peace of mind you might "Mic" (measure with calipers) the rod diameter and the bearing ID. Use the skinny tips of the calipers to measure the ID and not the thick part, you know. You should find the rod smaller than the ID by a bit. Then you know it will go.

[betacrash]

well i measured the the rod and it is .625. the i.d. of the bearing is .623. This sucks. I have no idea what to do now. Would it help if I hit the inner ring with a torch for a couple of seconds?

[betacrash]

well, the torch idea blew chunks. I had the idea of putting the bearing on my spindle sander since it has a cylinder that is about 5/8" (thinking that it could take off a few .01") I held the bearing while it went but it didnt seem to do much, either it is no match for the metal or my cylinder needs to be replaced. Once again.....this sucks.

[TheRic]

Are sure about those numbers, double / triple checked them?

I would suggest putting the rod in a drill, and sanding down the end. Having a chuck big enough would be the hard part. Sanding the rod down will probably go better than sanding the bearing. Those bearing are probably hardened steel.

Don't use a torch, you could ruin the bearing in a heartbeat.

[wardprobst]

well, the torch idea blew chunks. I had the idea of putting the bearing on my spindle sander since it has a cylinder that is about 5/8" (thinking that it could take off a few .01") I held the bearing while it went but it didnt seem to do much, either it is no match for the metal or my cylinder needs to be replaced. Once again.....this sucks.

Take the rod and bearing to a machine shop. It'll take them all of five minutes to put the two together. They do this stuff every day.

DP

[bmyers]

well i measured the rod and it is .625. the i.d. of the bearing is .623. This sucks. I have no idea what to do now. Would it help if I hit the inner ring with a torch for a couple of seconds?

That's great news! You 've only got .001 or so to go an you're there!

First, keep using the mic and some 600 grit, or 1000 if you are heavy handed. Try to sand evenly by wrapping the sandpaper around the steel rod and twisting it. Keep turning the rod 180 degrees in your grip so you are sure to sand evenly. Just a couple twists at a time then hit it with Scotchbrite. Check it with the mic. Also make sure you're not measuring some possible burr on the bearing sleeve and that the true inside diameter of the sleeve is .623 .

Creep up on it slowly. You do not want a loose fit here. Like I said, this process took much longer than I thought it would but it's important stuff. A vibration in this part of the machine will make it well, you know..

Try to improvise the same sort of setup that I did in my earlier post to assemble the bearings once you've got the two pieces a little closer together in diameter.

A tapping force it all it will take. The force you use to try to pound it in there is less than what it will require to remove it if it's not going to fit..

Remember this is Shopnotes so I think you're supposed to enjoy building it. You having fun yet? []

I bought an extra motor for mine also but I used the sander on the TS to true the drum and test it out. It works REAL nice and is a pleasure to use. I still haven't made a base for it but for now, that’s fine. I plan on moving soon so building big stuff isn't a good thing for me.

On the plus side on mounting it on the BT is that fact that I can use a router speed controller on the motor. Slowing it way down made it easier to sand the drum when it came time to true it up. At the designed speed in the book, it was still going too fast for me and heated up the glue in the laminated drum, clogging the paper and sanding poorly. At a much lower speed there was little heat and smooth accurate sanding. It's also handy while using the sander too. It's not that easy to crank a 16" wide board through there fast enough with the drum going full speed over and over again..(i.e. I'm still hunting for an exercise tread mill to steal some parts from)


Oh and leave the torch out of it for now.


Bill

[LCHIEN]

well i measured the the rod and it is .625. the i.d. of the bearing is .623. This sucks. I have no idea what to do now. Would it help if I hit the inner ring with a torch for a couple of seconds?

Are you sure you measure the bearing ID correctly? Good caliper technique is essential that the ID tips on the top are used and inserted the minimum distance and not angled which make the reading too small. Its much easier to measure an OD correctly than an ID.

If it is .623" then the bearing is defective, but that's not a likely thing. The ID tolerance is likely to be something like .625"+.005/-.000

Try inserting the shank of a 5/8" drill bit that you've checked the diameter of with the calipers.


P.S. According to the ABEC tolerances for precision ball bearings, the loosest tolerance for the bore hole (ID) is like +.0000", -.0003" That's pretty tight tolerances.

http://www.pacamor.com/abectolerances.php

[betacrash]

its amazing what a hammer, a pipe, and pure retard stregth can do. i measured and remeasured. It was .623. i was able to just pound on the inner ring of the bearing by using the pipe. for every 30-40 swings it moved 1". im so tired i cant even type any more.