Bandsaw Tracking – Revisited

[everettdavis]

There have been a host of folks who have posted many times that the Shopsmith Bandsaws are designed unlike other Bandsaws, and what one knows of the others simply does not apply to Shopsmith.

I have not entered into that discussion in any great capacity through the years for a variety of reasons.

Most discussion surrounds the issue of how the Shopsmith Bandsaw tracks the blade and how they believe it works.

I have been researching it in the background for a long time. Recently on an extended break I did some more research and obtained the Original patent -2,903,027- for Shopsmith Blade Tracking and Guiding Mechanism for Band Saw Construction.

I has numerous cross-sectional drawings, annotated with numbers in text explaining exactly how the design is supposed to work, and contrasts in the text why and how it varies from other Bandsaw designs.

Again, I am not going to weigh in with comment, as the inventors themselves do that so methodically within the patent application:


• Filed - patent 2,903,027 13 - Feb 1956 and awarded 8 Sep 1959 to Yuba Consolidated Industries, Inc. San Francisco, CA. a corporation of Delaware.

This document answers questions on how it was supposed to work, originally.

The PDF of the Patent 2,903,027 is attached.

Everett

Shopsmith Blade Tracking and Guiding Mechanism Patent for Band Saw 13 Feb 1956.pdf

(1.03 MiB) Downloaded 861 times

[dusty]

Very interesting and very informative read. Thank you, Everett for the time spent and the effort expended to provide this document.

I'll have to read it two or three more times before I begin to think I understand it all but that is good.

[everettdavis]

You are most welcome my friend, and mentor.... Don't get to do that very often.... It's almost always the reverse.

Sort of in that vein, but for others who are not as familiar with the Bandsaw features as you, I have been asked why the blade guides have the odd angles on them opposed to being flat. That too was first documented in the original Bandsaw manuals.

As part of a work-up I was once working on for a Bandsaw documentation piece that I may later decide to actually write, I extrapolated a photo and text of that, adding some color to illustrate what they were designed to achieve.

Blessings,

Everett

Bandsaw Angled Guides allow wider throat for cutting.png (586.01 KiB) Viewed 6537 times

[dusty]

As I continue to study this document, I become even more impressed by the design. The detail regarding blade tracking about the upper and lower wheels (referred to as pulleys in the document) teaches me that I do not fully understand the physics of this design. Why does the blade tend to track to the greater circumference of the "pulleys"? Figure 17 in the document.

[JPG]

As I continue to study this document, I become even more impressed by the design. The detail regarding blade tracking about the upper and lower wheels (referred to as pulleys in the document) teaches me that I do not fully understand the physics of this design. Why does the blade tend to track to the greater circumference of the "pulleys"? Figure 17 in the document.

I have not(yet) read the pdf above, but I think the same reason a blade tracks to the greater diameter(the high point on a crowned pulley).

[dusty]

As I continue to study this document, I become even more impressed by the design. The detail regarding blade tracking about the upper and lower wheels (referred to as pulleys in the document) teaches me that I do not fully understand the physics of this design. Why does the blade tend to track to the greater circumference of the "pulleys"? Figure 17 in the document.

I have not(yet) read the pdf above, but I think the same reason a blade tracks to the greater diameter(the high point on a crowned pulley).

And Figure 18.

[rcplaneguy]

Interesting! We have wondered what the “cant” of the upper wheel should be, now we know! 1 degree, 37 minutes.

[JPG]

Interesting! We have wondered what the “cant” of the upper wheel should be, now we know! 1 degree, 37 minutes.

Iiuc, the upper wheel. Cant angle is 1 degree 15 minutes.

[beeg]

Iiuc, the upper wheel. Cant angle is 1 degree 15 minutes.

So WHAT is that in inches?

[JPG]

Iiuc, the upper wheel. Cant angle is 1 degree 15 minutes.

So WHAT is that in inches?

??? An angle is not a length.