Stamped vs Machined washer (behind stone)

[Calvin Wrightsman]

I recently bought a T-3 (on Saturday, March 31st.) from the Woodcraft store in Lenexa, Kansas.   I got it home, unpacked it, put the stone on, and turned it on.  There was a noticeable wobble (run-out) in the stone, so I took it back to the Woodcraft store.  The gentleman at the store noticed that the heavy thick washer that sits behind the stone was stamped out rather than machined, and therefore, the two sides were not parallel, which caused the wobble.  After some grinding on the washer, he had eliminated almost all of the wobble.  From my place in Topeka, Kansas, USA to the Woodcraft store in Lenexa, Kansas USA is 69 miles one way.   Therefore, I had to drive an extra 138 miles (plus the high cost of gasoline) all because of a stamped washer rather than a machined one.  Has anyone experienced this same problem on a brand new machine?  Thanks.

[Mike Fairleigh]

Calvin,

I don't have a good answer for you, but wanted to say hello since I live in Olathe.  I've been using a T-7 now for about 5 months.

I believe my washer is stamped also, however it's flat/coplanar enough that I don't have any wobble.

[jeffs55]

It hardly seems likely that the mere fact that a washer was stamped instead of machined would cause such a problem. It seems like tremendous overkill to machine a washer anyway. I have never thought to look but I doubt that I have a single "machined" washer in the house. Now,  a poorly stamped one made from a flat blank that did not have parallel sides to begin with, I can understand that. If your salesman actually ground a washer to a flat state then he is a great salesman but a little uhhhhhhhh not to smart. I would have just gone to the washer section and found you a flat one.

[Ken S]

A test of (some) grinders in the latest issue of Fine Woodworking addresses the problem of pressed flanges.  The author was able to minimize runout by marking and rotating the flanges to mostly correct wheel runout.  This sounds like the same issue with the washer on the Tormek.

The article would have been more useful if the $200 max price grinders had been compared with something like a Baldor.  The issue with the flanges was somewhat glossed over, more attention being given to the wheels and rests supplied with the grinder.  Several of the grinders being tested had improved smoothness after rotating the pressed flanges.  Incidentally, only a "best value" was awarded for the cheapest of the group, no "best". That would tell me the evaluator didn't think much of the group.

Either finding a flat washer or correcting one should not be difficult.  The washer should lay flat on a flat surface such as a table saw top or glass.  The thickness should measure the same around it as measured with a micrometer, dial indicator or caliper.

This is another post which should be addressed by the technical staff of Tormek AB.  Please post.

Sorry that I am presently unable to test my washer, as my Tormek was recently stolen.

Ken

[Mike Fairleigh]

Actually a replacement stainless washer isn't that easy to find, assuming you want to match the original's dimensions.  Even McMaster doesn't seem to have them.  It's a 12mm x 36mm x 5mm. (I assume the T3 is the same as the T-7, but I'm not certain of that).

I do agree that any wobble in either wheel probably has more to do with either defective wheel(s) or a bent shaft than it does with the washer.  Still, this thread caused me to take my washer off and give it a closer look.  I decided it couldn't hurt to take a few light polishing passes over a 1,000 grit waterstone on each side.  You can see that on the flat (stone) side, there was an uneven ridge almost all the way around the outer edge, and another ridge around the inside diameter.  This is to be expected with a stamped steel part, but I do feel better about being rid of it. 



On the machine side, the polishing slightly increased the contact area with the nylon bushing - not that any more contact is needed:

[Ken S]

Good job, Mike.

Did you happen to measure the thickness at different points around the circumference? Flattening both sides on your waterstone should take care of the flatness issue.  If the thickness is the same throughout, it should also be parallel.

In defense of Tormek AB, the Tormek grinders are continually evolving.  Jeff has written an interesting blog (on the Sharptools website) about the evolution of the universal support bar.  I purchased my T-7 about three years ago.  Even in that short time, the EZY lock shaft has been designed and is now standard; the AWT improved water trough is now standard; the drill sharpening jig is available.  A revolving base attachment is just hitting the market.  The Tormek designers have not stood still.

When rusty shafts became an issue, the shaft was redesigned in stainless steel.  We may be seeing a future modification/improvement in the making.  Future units may come with machined washers. 

In my opinion, what really makes the Tormek company outstanding, is that these improvements can be retrofitted to all the past machines.  That is commendable.

I know first hand that this forum is followed by the Tormek company in Sweden.  I hope they will post on this issue.

Jeff, I assume you have been with this forum from the start.  Has the washer issue come up before, or is this something new?

Ken

ps, very good photography, also, guys.

[Mike Fairleigh]

Ken, I meant to, but forgot, to take a careful thickness measurement after the polishing.  I did put the caliper on it in one spot and measured 5.04mm in that area; the "light test" seemed to indicate that it was co-planar.

[Jeff Farris]

Your assumption in searching for a perfectly parallel washer is that the mating surface of the grindstone is perfectly flat as well. Not a very good assumption.

There will be imperfections in both. What I have always done to minimize run-out is to unlock the nut, turn the washer a quarter turn while maintaining the position of the grindstone and then locking the nut.  Somewhere around the circumference of the two mating surfaces, you'll find the "sweet spot" where the run-out is at its minimum.

[ironduke]

If you use Jeff's solution (a good expedient) then you should mark the shaft, wheel and both washers so you can re-assemble/re-mount the wheel in the same orientation.  Also remember the "hammer tap" when mounting on the old-style shaft.  Things have to be tight, but not toooo tight.