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Mark 7 saw blade runout
Posted: Wed Mar 19, 2025 10:46 pm
by Linusofs
I have a brand new Mark 7. I noticed some wobble in the saw blade so jury rigged my digital caliper as a dial indicator of sorts. I see about .015” wobble in the blade near the teeth. I measured this several times with two blades. For grins I did the same in my 44 year old Mark V and only measured about .001”. Then I measured the kerf width using a 1/8” wide blade. The kerf measured about .145”. This seems consistent with the wobble I measured.
So I tried chucking up my longest straightest drill bit (1/2” about 6” long) and checked for “orbit”. I could see some orbit at the tip but didn’t have a way of measuring it.
Has anyone else seen this? What is deemed acceptable?
Re: Mark 7 saw blade runout
Posted: Wed Mar 19, 2025 11:52 pm
by DLB
Was the measurement with a new blade and arbor that came with a Mark 7? If yes that seems pretty high to me as the new blades that I've bought have had low (but unspecified) runout. I've also seen earlier blades have runout in this range. I suggest putting a lathe faceplate on the spindle and check for runout in case you have a spindle problem.
Tom on Youtube's Woodshop Nerdery did a video on spindle runout and other subjects, IIRC he had received a new Mark 7 with excessive runout and SS replaced his quill. I think it was this one: (
https://www.youtube.com/watch?v=HEFFYw29yV4) but it might have spanned a couple of episodes.
Some higher end blades specify runout. For most of their blades Forrest specifies runout at 0.001" and in their advertising say that 0.004" to 0.010" is common for other brands.
- David
Re: Mark 7 saw blade runout
Posted: Thu Mar 20, 2025 2:12 pm
by chapmanruss
Linusofs,
Just curious if you used the same Saw Blade and Arbor when you tried it on your older Mark V.
Since you also tried a Drill Bit and saw some "orbit" I would suspect the problem is with the Quill assembly.
Re: Mark 7 saw blade runout
Posted: Thu Mar 20, 2025 5:16 pm
by dusty
I would be asking Shopsmith for directions. Let them decide what needs to be rrplaced so they can ship the appropriate replacement parts.
Re: Mark 7 saw blade runout
Posted: Thu Mar 20, 2025 10:14 pm
by GetterDone
With the Info that has been shared,
I will add that a Dial Indicator or Dial test indicator can be used to make sure that things are Running True.
I get most of my Indicators for work like this from a company called CDCO,
http://cdcotools.com/
I hope this Helps.
Start with Checking the shaft itself, then everything you add to it (Arbor/Etc.) can cause more Runout.