Band saw guide bearings

[jsburger]

Two things come to my attention:
1) Assuming the picture is NOT upside down, the blade teeth direction is backwards.

2) The bearings do not appear to be tight against each other. The inner races should be jammed against each other. There should not be a gap between the outer races.

As an aside, the 'new' SPT parts pages in the website suck. More about that in a separate thread.

It was an attempt to determine if the pix was upside down that that suckiness was discovered.

I was going to say exactly the same thing. Then I realized the OP is talking about the guide bearing on the left side by the tensioner not the back up bearings. So the picture is correct and right side up.

[JPG]

Ya the back side!




What goes down MUST also go up(somewhere)!

[DLB]

I was FINALLY able to get back in my shop after weeks of too cold weather. I we sawing again today and had the same issue, but even worse. This time I paid more attention to the PowerPro and noticed the output shafts (all of them) slowing or stopping but the speed indicator staying about the same. So, I don't think the problem is the bearings. There is something wrong with my PowerPro. I have contacted Customer Service (this is a brand new machine).

Regarding the original post about the blade wedging "between" the bearings, it was the "guide" bearings, not the backup bearings. It still does work its way between the bearings a little.

Since you said all of the output spindles are slowing or stopping but the indicated speed is correct, I would say your lower Poly-V belt is slipping. If the upper belt was slipping, then the Idler shaft (lower aux) would be spinning normally. RPM indicated is the upper spindle speed, but it is actually measured in the motor and converted from motor RPM to output spindle RPM. Therefore, the displayed RPM ASSUMES no slip. As a Gen 1 guy, I'm not familiar with the tightening procedure on Gen 2. It will have something to do with adjustments made between the two parts of each motor mount. Be careful with this, if the adjustments are similar to Gen 1 then they adjust both motor position and the pitch of the motor shaft.

The bearings are definitely a problem, as others have said.

- David

[RonKlein]

There are known problems with the set screw in the motor pulley loosening, and allowing the pulley to slip on the motor shaft. If this is your situation, consider using some Loctite on the set screw before tightening it.
Ron

[chapmanruss]

Linusofs,

The Auto Track Blade Guide Bearings seem to be separated a bit allowing the blade to "wedge" in between them. The bearings should be tight together so no gap between them. This results in a small groove the blade will track on. Also make sure the bracket is adjusted correctly so the blade rests in the center of the two bearings.

The link below is the PDF for the Bandsaw Retro-Kit Instructions. Check to see if your Auto Track Blade Guide Bearings are installed as per the instructions.

https://www.shopsmith.com/_files/ugd/d5 ... 09e1c8.pdf

I have put/had this Auto Track Blade Guide Bearing assembly (2 bearings) on several Bandsaws and none have had the amount of gap yours has.

[Linusofs]

Sorry, I’ve not been on the forums for awhile. The picture is not upside down. The blade rises on the left side of the machine. The bearings could not be any tighter (I tried multiple times). The inner bearing races prevented them being any tighter. I put back the bronze bearing version that is one piece. It still works fine.

I did have a loose belt that was slipping. I tightened that up and it works “perfect “ now. I still don’t know why the two bearings wouldn’t work.

[DLB]

The bearings could not be any tighter (I tried multiple times). The inner bearing races prevented them being any tighter.

IIUC you are saying that the inner races are in full firm contact with each other but the outer races have a gap wide enough for the blade to enter.(?) It seems to me that one or both bearings would have to be bad for this to happen. I'm no ME, but I'd think a gap of 0.002" here would be excessive.

- David

[chapmanruss]

Linusofs,

Sorry to hear you are still having troubles with the Auto Track Blade Guide Bearings. Since they are butted as close as possible and still have the problem I ask again if they are Shopsmith OEM Bandsaw Bearings or are they from another source?

The picture below shows the Shopsmith OEM Bandsaw Backup Bearing Upgrade that includes the Auto Track Bearing pair. The inner race is flush with the outer race and therefore does not leave a gap between the outer races.

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Bandsaw Backup Bearing Upgrade.jpg (86.12 KiB) Viewed 28134 times

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The picture below shows the Auto Track Blade Guide Bearings that were used to upgrade a 1984 Bandsaw I restored. You can see there is no gap between the bearings since the blade is not tensioned. Once the Blade is tensioned the center between the two bearings would be directly behind the Blade when the Auto Track Blade Guide Bearing Assembly is correctly aligned. There is a small amount of adjustment allowed by the bolt that holds the Assembly to the Bandsaw's Main Frame.

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Auto Track Blade Guide Bearings.JPG (157.12 KiB) Viewed 28134 times

[Linusofs]

Yes, these are OEM bearings from Shopsmith. I received the kit that you pictured above. I had all the same thoughts eveyone above had and double checked that I had installed the bearings per the instructions and double checked that all four bearings were identical (they were). I finally gave up and but the old bronze bushing bearing back in (single piece) and it is working fine. It was not worn out like the backing bearings were.

[chapmanruss]

Since the Auto Track Blade Guide bearings are now out of the Bandsaw you could check them to confirm the problem. With a straight edge against the face of the bearing check if the inner race is further out then the outer race. You could do this on both sides of each of the 2 bearings. This would confirm what the problem is with these 2 bearings. I would be curious to know what you find. If this is the case, I would recommend contacting Shopsmith and report this problem. If this was a recent purchase, they should make it right.

As you have found it is not a problem with the single bearings used in the upper and lower guides.