Shopsmith Forums

Fellow Geniuses,
I have had an on going issue with my 1983 Mark V 500. We have a fellow member that has a brand new Mark 7 PowerPro Plus that is dealing with the same issue on his new machine.
The problem stems from what I describe as blade wobble. On my machine when the blade slows you can actually see where the blade does not swing true. It appears to wobble. I just had my headstock completely rebuilt. It has a single bearing quill that was rebuilt. I also bought a new 5/8th arbor. I noticed the blade movement on day one. Knowing the machine was solid I thought I had a bad arbor. I bought a new arbor. I still have what looks like a wobble. We tried several different blades. I still have what looks like a wobble. We put the machine in drillpress mode and installed a brad point bit. It Drilled straight and true. Zero bit walk or knock with a brad point or a forstner drill bit. I gave up. It is what it is.
I have been helping a new member along with his new 7 PP+. He is experiencing the exact issues that I have. Like me he bought a new arbor. Like me he has tried multiple blades. He describes his wobble issue exactly the same as mine. EXACTLY! Our fellow member is genuinely frustrated with what is obvious to the eye. That blade is not true. I could add more words but it would be blah blah blah. I/we are open to any thoughts ideas or criticism on the issue of what appears to be blade wobble. Ideas PLEASE!

Is the blade warped? Are you tightening the arbor nut correctly? Did you try a different arbor? The fact that you can drill OK with different style bits indicates that you do not have a headstock problem. The problem most likely has to be in what is being attached to the quill shaft and the methodology used to attach the components. One other thing is that the arbor mounting hole has been drilled at an angle rather than straight into the arbor. The accurate drilling suggests strongly to me that you have some kind of a funky arbor.
Bill V
PS You mentioned another member. Is he a member of this forum? If so please have him check in here to add to this discussion. Also what is your location? We may have someone close to you who can help.

Correction noted!
Both machines each have a new arbor. Bought by both users to confirm if our original arbors were bad. Second, on my machine we ran 4 different blades. My machine = 2 Arbors, 4 different blades. I bought a brand new arbor from ShopSmith to try and correct the issue. New Arbor and 4 blades later the problem is exactly the same. Me? I live in Portland Oregon.
YES! The other owner with the M7 PP+ Is a member on the forum. He bought a new ShopSmith arbor to null out the wobble issue. That did not work. He then bought a very nice Uber high quality blade. He still has a wobble. All new gear to the quill shaft and my 35 year old machine responds just like his new M7PP+.
Trust me, I have spent hours looking and thinking about this issue. On my machine everything is new or rebuilt.
Thank You!

How wide of a blade do you have and how wide is the kerf that it cuts?

If you have wobble, the kerf will be wider than the blade.

Can you measure shaft run-out with the arbor removed?

Thomschuck wrote:Correction noted!
Both machines each have a new arbor. Bought by both users to confirm if our original arbors were bad. Second, on my machine we ran 4 different blades. My machine = 2 Arbors, 4 different blades. I bought a brand new arbor from ShopSmith to try and correct the issue. New Arbor and 4 blades later the problem is exactly the same. Me? I live in Portland Oregon.
YES! The other owner with the M7 PP+ Is a member on the forum. He bought a new ShopSmith arbor to null out the wobble issue. That did not work. He then bought a very nice Uber high quality blade. He still has a wobble. All new gear to the quill shaft and my 35 year old machine responds just like his new M7PP+.
Trust me, I have spent hours looking and thinking about this issue. On my machine everything is new or rebuilt.
Thank You!

What is YOUR definition of wobble? You stated in your original post ...

"On my machine when the blade slows you can actually see where the blade does not swing true."

What does that exactly mean? Does the blade cut true at speed? If so then are you seeing an optical illusion at slower speeds?

Different machines, different arbors, different blades none of this makes any sense.

Blade wobble is supposedly one of the reasons that Shopsmith makes their blades with 1 1/4" diameter holes. Common sense says that the larger the mounting point of the blade, the less it will distort and wobble. It might work that way, but even the larger arbor might not be able to eliminate all wobble in the blade.
Does the wobble seem to affect the cuts you make with the saw? If not, then it doesn't matter. If you get poor or too wide cuts, then it might be worth pursuing farther.

Thank you for your replies.
Read this part please! I have tried every combination in the book to get my blade to run true.
Define wobble.... When my blade slows down it is not in a straight edge line. I put a Starrett scale Up against the blade so it is touching. I turn the blade with the SPT PTO. It no longer touches the blade. Like the blade is bent. Four bent blades, no way. One is a brand new Forrest blade.
I put a thin kerf Systematic blade on the machine. I made a cut into a piece of Walnut stock. I measured the cut. YES it’s wider than the kerf on the blade. I put on a brand new Forrest blade and measured that cut. It’s slightly wider than the kerf on the blade, but not much. It is almost like the blade is being mounted at an angle. If you listen to the blade you can hear the blade make contact then no noise, then contact, then no noise. Maybe one tweaked blade but not 4. maybe a bad arbor, but not two, one being brand new. Then in talking to Bill a new member with the M7 PP+ I discovered he is struging with the same issues. I know, WEIRD. Help? My question is define run out? I know play and I know runout. Note. It’s a very symmetrical problem.

If you have a sanding disk try it and see if you get the same results. The larger diameter should amplify the wobble if it is due to the quill and you will have eliminated any arbor issues. I think you have already eliminated the blades as the problem.

Is the table absolutely true to the blade?

If I press on my main table when its is only 2 post supported, it does have some movement if it is not supported by the
auxiliary table/legs. Is it possible the main table has some movement rather than the blade?


b

Do you have a dial indicator that you can use to measure runout, if any, of the bare spindle?