My 520 started singing today.

[dynabase]

I looked at the picture I posted on page 4 (#320) and it looks like it's 1 3/4 but I will confirm it again on Sunday.

Michael

[dusty]

I looked at the picture I posted on page 4 (#320) and it looks like it's 1 3/4 but I will confirm it again on Sunday.

Michael

It should be 1 3/4". I checked all of my arbors this morning. I posted this earlier but without dimensions.

[dusty]

Arbor to Blade #1.jpg (171.28 KiB) Viewed 5223 times

Arbor #2.jpg (133.68 KiB) Viewed 5223 times

Maybe a closer look and these two images will tell us something. I know I read the measurements incorrectly.

[reible]

Arbor to Blade #1.jpg

Arbor #2.jpg

Maybe a closer look and these two images will tell us something. I know I read the measurements incorrectly.

I'm sure they are telling us something but I'm not sure what. If you go back and look at my images you can see the blade to the center of the allen screw on the silver collar is 2" while in his shot it looks to be 1-13/16".

I may have to go out and dig up one of my old 500 arbors to look at. From memory I think they are a lot shorter...... so are there other arbors from shopsmith that are only slightly shorter?

Ed

[reible]

As I remembered the 500 arbor is a lot shorter. Here is a picture, looks like about 1-5/16" (sorry, I for got to actually measure so I'm using the picture to get that dimension) to the same place the other arbor measures 1-3/4". That would be 7/16" shorter.

20170507_091701_resized.jpg (263.51 KiB) Viewed 5210 times

Ed

[JPG]

My comparison on a couple of arbors yields about a 1/2" difference in the distance from the headstock end of the arbors and the INSIDE surface of a blade (1 3/4 vs 1 1/4).

Dynabase's 1 3/4 was to the OUTSIDE surface of the blade.

Also there is parallelax/staightness/zeroing issues with some of these pix of measurements(Ed's look good).

I have concern re the spacer that appears to have instances of both 1 3/8" and 1 7/16" lengths in other threads.

Also in Dynabase's pix of the spacer abutting the carriage etc., there appears to be a lip.

Additional confusion, but I think relevant to understanding the 'issue'.

Problem is, we have not(yet) explained that apparent 1/4" anomaly.

When comparing arbors that have a fixed distance blade mounting surface on opposite faces of the blade, the blade thickness must be considered.

[JPG]

Sonething else we need to look at is the collar and the length of the quill shaft extending beyond the collar as well as whether the collar extends the proper distance from the end of the quill body.

Thus the relevant measurement points are, face of quill bore in headstock(zero reference), rubber bumper, end of quill body*, outer face of collar, inner/outer face of blade surface on the arbors.

* This assumes the end of quill body to inner surface of the retaining ring/stop is constant.

[dusty]

I have had two different size rubber bumpers. I had a new one from Shopsmith on my Shorty but have taken it off and put the old one back on. The three new ones that I got from Shopsmith (two different requisitions) were shorter than what I already had.

There is a small "bump" on the headstock right where the bumper makes contact. It exists on both of my headstocks. It holds the rubber off the headstock by about an 1/8". I THINK that it is there to compensate for the contour of the headstock.

Yes - there is something to be learned from Eds' methods. Conclusions drawn using Eds' photo images are much more likely to be correct than from others. Parallelax being the major issue. Eds methods avoid that.

I would still like to see a photo of the dnabase saw blade as it comes up through the table cutout (without a table insert).

With regard to blade thickness, I prefer to work with the left face of the blade as the reference surface. This remains the same no matter which blade you may have mounted.

[dynabase]

I checked the arbor and it is 1 3/4.

The main problem is with the trunnions. I cannot move my table at all because of the rear trunnion. I am waiting on a reply from Shopsmith support and will either get a new trunnion from them or drill this one out. Until then I don't know what else we can do. If you want me to reassemble the maintable with the old trunnions and take a picture I will be happy to do so. I think it would be better to see what we have after I get the trunnion thing resolved.

With the new trunnion I will be able to adjust the table some. The 1/4 inch difference between the two sides of the blade when measured using the miter slots should be different. If I could move the table 1/8 of an inch that might balance things out some.


Michael

[dusty]

Am I correct? The one trunion has 1/2" holes and the other has 3/8" holes (1/8" smaller). If I am correct, the larger holes will give you 1/16" more movement in any direction than you have now.

Will that extra movement alleviate your existing 1/4" error?