Table Line Up
Posted: Fri Apr 30, 2021 9:18 am
If the saw blade is parallel to the miter track is the table considered lined up.
A woodworking forum for woodworking hobbyist and woodworking projects related and unrelated to the Shopsmith MARK V
https://forum.shopsmith.com/
edflorence wrote: ↑Fri Apr 30, 2021 1:16 pm Basically, yes. But, there has been much electronic ink spilled on this forum discussing just how parallel is parallel and how best to determine it.
I don't see how there could be consensus. The accuracy needed depends on the work being performed. The procedure in the manual (there are many variations) doesn't quantify the error and is clearly close enough for a lot of work. I doubt that it reliably produces results better than 8 or ten thou over a distance of 8". Which is not good enough for many of us as individuals or for the work we're doing. Taking us down a path with variations in technique and the equipment we're using.
Yes, I suppose you are right. There can be no consensus - for a variety of reasons.DLB wrote: ↑Sat May 01, 2021 8:31 amI don't see how there could be consensus. The accuracy needed depends on the work being performed. The procedure in the manual (there are many variations) doesn't quantify the error and is clearly close enough for a lot of work. I doubt that it reliably produces results better than 8 or ten thou over a distance of 8". Which is not good enough for many of us as individuals or for the work we're doing. Taking us down a path with variations in technique and the equipment we're using.
- David
In the interest of safety I think we should be clear about these precision numbers. I infer that you're referring to accuracy of a cut, as in +/- 1/32" in the length or width of a board. Not an angle representing deviation from parallel, like 1/32" over 8" between blade plane of rotation and miter tracks. That, to me, would be a very large and potentially unsafe error.dusty wrote: ↑Sat May 01, 2021 10:23 am If asked, over the years (especially the last few), my answer would have been a constant contradiction. Today I am inclined to say that I hardly ever strive for precision better than 1/32" (.03125"). Why? Because I no longer see well enough to shot for 1/64" (.01563"). I might even concede that the Shopsmith can not hold tolerances any tighter than that.
The numbers that I stated thus far in were intended to quantify characteristics of a cut piece of wood and have nothing to do with blade to table alignments. If I rip something 6" wide I want it to be 6" within the tolerances so stated. Very good points you make.DLB wrote: ↑Sat May 01, 2021 11:51 amIn the interest of safety I think we should be clear about these precision numbers. I infer that you're referring to accuracy of a cut, as in +/- 1/32" in the length or width of a board. Not an angle representing deviation from parallel, like 1/32" over 8" between blade plane of rotation and miter tracks. That, to me, would be a very large and potentially unsafe error.dusty wrote: ↑Sat May 01, 2021 10:23 am If asked, over the years (especially the last few), my answer would have been a constant contradiction. Today I am inclined to say that I hardly ever strive for precision better than 1/32" (.03125"). Why? Because I no longer see well enough to shot for 1/64" (.01563"). I might even concede that the Shopsmith can not hold tolerances any tighter than that.
Nick had some fuzzy math, Sawdust Session 1 IIRC, determining maximum error from parallel for a 'typical' blade. I'm reluctant to repeat here, too much deviation from typical. But, the message remains good. You do not want the deviation from parallel to be large enough that the work contacts the body of the blade. At best, this causes binding and burning and at worst a kickback. Smaller errors cause the system to work harder to create a wider than intended kerf, and can result in angle errors in some setups.
- David