I was using a sanding disc on my 520 yesterday, to dress some bandsawn edges to the layout lines. I initially had the 520 set up for table sawing, with the quill fully retracted, and the table carriage against the rubber bump-stop sleeve on the way tube. This places my saw blades pretty close to the center of the slot in the table insert. But when I changed over from the saw blade to the sanding disc, I had to move my table about 1/4" to the right in order to align the sanding disc with the slot.
I had noticed this before, but had never bothered to track down the reason why. Searching the Shopsmith website and this forum just now didn't shed any light on the subject. I do recall that Shopsmith used to offer a longer sanding-disc replacement arbor, to convert the older short-arbor discs (designed for Mark V/500 machines) for use with 505/510/520 machines.
Raw data:
I'm 99.9% sure that I have the correct saw-blade arbors for my 520. Both the 5/8" arbor and the 1-1/4" arbor measure 1-11/16" from the blade to the female end of the arbor.
My sanding-disc arbor measures 2-1/16" from the disc to the female end of the arbor.
Questions:
Do you guys have the same issue on your 505 / 510 / 520 / Mark 7 machines?
If so, why would Shopsmith have designed the newer sanding-disc arbors to be 1/4" longer than their newer saw-blade arbors?
I can confirm that the sanding disc arbors are longer than the blade arbors by about 1/4".
I can not offer an explanation for why. I very seldom position the sanding disk in the table cutout. I use the sanding disc with the main table position off to the right of the blade OR with no table at all. I also often mount the disk on the other end of the spindle.
Conical Disk???
"Making Sawdust Safely" Dusty
Sent from my Dell XPS using Firefox.
IF there is an engineering reason for it, perhaps it has to do with optimizing for dust collection.(?) Just a guess on my part. I had not noticed this as I don't use the bumpers. I like to set my saw up with the quill slightly extended to allow for fine adjustments in blade position using the quill, an old habit from my pre-500 days. I have a few bumpers but most are on the small side and don't work with this practice.
Since the table is movable, it seems like a non-issue to me. I always adjust things so my blade/disc, or whatever I'm using is positioned in the slot the way I need.
I really cannot give an answer for that either. Like Dusty I usually have my sanding disk positioned next to the table rather than in the table slot. Doing that I really haven't paid much attention to setting up the sanding disk in the table slot. Shopsmith did sell a Disk Sanding Table Insert but appears that has been discontinued. The slot in it is about 3/16" wider than the Saw Blade Table Insert and the length is slightly different at both ends. That additional width is towards the headstock side of the insert so that would not be the reason for the longer arbor on the Sanding Disk. The Lower Blade Guard for the Mark V 505, 510, 520 and Mark 7 was designed to be used with the Sanding Disk for dust collection. There is a stripped down version of the Lower Blade Guard for the Mark V 500 and original table system for Sanding Disk dust collection. Even that doesn't give us any answers to why the longer arbor on the sanding disk.
Russ
Mark V completely upgraded to Mark 7
Mark V 520
All SPT's & 2 Power Stations
Model 10ER S/N R64000 first one I restored on bench w/ metal ends & retractable casters.
Has Speed Changer, 4E Jointer, Jig Saw with lamp, a complete set of original accessories & much more.
Model 10E's S/N's 1076 & 1077 oldest ones I have restored. Mark 2 S/N 85959 restored. Others to be restored.
I have disks with different sized arbors. I was under the impression the difference had to do with the differences between the old and new versions of the table and carriage (500 vs. 510 and later) but the comments here don't seem to confirm that. I thought you needed the longer arbor to use the disk in the slot of the larger table.
I don't ever recall noticing this. Perhaps because when I change to the sander for in table use I also change the table insert and have the table off to the side and not over the disk when I start. By the time I'm set up and slide the table over I don't recall any need to adjust the quill to get it to fit........
Next time I do a set up I will check this out. 44 degrees in the garage shop now so no desire to do it now.
Ed
{Knight of the Shopsmith} [Hero's don't wear capes, they wear dog tags]
edma194 wrote: ↑Mon Feb 01, 2021 12:29 pm
I have disks with different sized arbors. I was under the impression the difference had to do with the differences between the old and new versions of the table and carriage (500 vs. 510 and later) but the comments here don't seem to confirm that. I thought you needed the longer arbor to use the disk in the slot of the larger table.
The extended arbors have more to do with positioning the disc (or blade) within the lower blade guard on the 510/520 table systems for improved dust collection. The older sanding discs can be used on the 510/520, but not with the lower saw guard. I don't think that the table or carriage make any difference, except you might have to extend the quill. Personally, if I'm using the disc in the slot of the table I'm also using the lower saw guard and dust collector.
garys wrote: ↑Mon Feb 01, 2021 11:16 am
Since the table is movable, it seems like a non-issue to me. I always adjust things so my blade/disc, or whatever I'm using is positioned in the slot the way I need.
It is certainly not an issue. It is these seemingly meaningless differences that lend to the mystery of why.
"Making Sawdust Safely" Dusty
Sent from my Dell XPS using Firefox.
