Milled Pads on Fore and Aft Edges of Tables

[dusty]

On the fore and aft edges of the Shopsmith tables you find some milled pads. Each of those pads protrudes about 1/32" beyond the edges of the tables.

Would anyone care to explain what they are and why they are located where they are.

[Skizzity]

For the table spacers for the rail assemblies. A guess here, as evenly spaced as can be without hitting a miter gauge slot, trunnions, or table ribs? For clearance?

[Ed in Tampa]

I think the question has been asked before and if memory serves correctly they are registration pads used in milling.

[dusty]

I think the question has been asked before and if memory serves correctly they are registration pads used in milling.

Yeah, maybe it is a redundant question but I can't find where it was asked. The pads themselves are milled and the milled surfaces, fore and aft, are separated by exactly 22".

On the Main Table, the mounting holes for the front and rear rails are drilled into those pads. Could it be that that is their primary purpose; reference surfaces for the rails?

[reible]

Without access to shopsmith details we are again faced with guesses.

When parts are cast it is normal to have pads like these in place and to mill them to use as reference surfaces for other operations. Cleaver designers might also find these useful for secondary purposes.

The order of the milling also must be taken into account. Are these the primary operation on which the following operations are indexed? If the answer is yes then the miter slots which we have learned are cut at the same time could be referenced from these...... or some other operation might be done and then these done later for locations of say the drilled holes in the table..... Lots of possibilities.

Ed

[JPG]

My early 510 has those pads. The rails are registered to them.

Since the later 510 moved the location of the center rail mounting spacer and tables(some at least) have the pads at both locations, I think we can conclude they are there for that purpose at least. Whether they are also used as a reference surface for other machining is a matter of conjecture(guessing).

And yes they are 22" apart front to back.

[dusty]

Without access to shopsmith details we are again faced with guesses.

When parts are cast it is normal to have pads like these in place and to mill them to use as reference surfaces for other operations. Cleaver designers might also find these useful for secondary purposes.

The order of the milling also must be taken into account. Are these the primary operation on which the following operations are indexed? If the answer is yes then the miter slots which we have learned are cut at the same time could be referenced from these...... or some other operation might be done and then these done later for locations of say the drilled holes in the table..... Lots of possibilities.

Ed

I agree, Ed. Without access to the engineers' notes, this is all conjecture. But as an engineer and even more so 'as an engineering technician' I know that a lot of what ends up in the design is recovery from design error.

I think that the the center pad location could be just that.

By my way of thinking, the logical distribution would have been one stud/hole centered and the other two equally spaced toward the edges. As it is, the out board pads are set 1 1/2" in from the edges of the table. To have centered the remaining pad was prohibited by the location of the rear trunion; the pad was then moved, out of necessity, to one side. Which side is dictated by the location of the table cutout. So what do we end up with? The two outboard mounts inset 1 1/2" and the center mount offset 1" away from the center line and away from the table cutout.

It has been stated that older versions of the Mark 5/V utilized the other pad. I don't see how that would have been possible due to the rear trunions' proximity.

[JPG]

. . .
It has been stated that older versions of the Mark 5/V utilized the other pad. I don't see how that would have been possible due to the rear trunions' proximity.

The older version used tapped holes(no nuts to interfere with stuff under the table).

[JPG]

Also the holes were evenly spaced(7 1/4") and only had three pads.

So the extra pad was added for the new 'stud' hole location.