Rip fence and floating table

JPG · Post by **JPG** » Sun Feb 16, 2014 4:05 pm

dusty wrote:I believe, because I have been told so by Nick, that the pads to which you refer really have a dual purpose. Yes, they are the mounting points for the spacers used to position the rails (front and rear). But they are also the reference points used by the milling machines during manufacture.

As such, much more often than not, if the pads are out-of-spec this will be detected during the manufacturing process. I suspect that if we knew everything there is to know about what happened to your tables, there would be no mystery.

As it is, you are happy because your tables have been made to work properly. However, I am not convinced (and will not be because of my nature), that the situation is as simple as "they barely met specification and therefore needed to be shimmed". Shopsmith knows more than you have been told.

Not sure of that! SS did not say 'out' of spec. SS said Near max + and near max -. Assuming they were referring to the pads, a big skew could result.

Perhaps SS 'learned' the fallacy of statistical QA 'thinking'!:D

Naw, the sample size was too small!:rolleyes:

Wonder what the 'tolerance' is/was!

dusty · Post by **dusty** » Sun Feb 16, 2014 5:00 pm

JPG40504 wrote:Not sure of that! SS did not say 'out' of spec. SS said Near max + and near max -. Assuming they were referring to the pads, a big skew could result.

Perhaps SS 'learned' the fallacy of statistical QA 'thinking'!:D

Naw, the sample size was too small!:rolleyes:

Wonder what the 'tolerance' is/was!

This is the case for many different settings/adjustments in the Shopsmith realm. They just do not speak to tolerances as much as I would like. I, therefore, have established many of my own work to specifications.

I have a grandson-in-law who is working to become a "machinist". I am trying to get him interested in exploring some of those self established tolerances to see if they can/should be tightened.

I had a discussion with him about the floating tables (with reference to the fixed table) but I could not get him to take the bait. I may have to sink to offering a steak on the outdoor grill to get his attention.

We eat AFTER we work. A rule previously learned and learned well. I fire the grill when we are about to quit.

algale · Post by **algale** » Sun Feb 16, 2014 5:29 pm

JPG40504 wrote:Not sure of that! SS did not say 'out' of spec. SS said Near max + and near max -. Correct, that's what SS (Jim McCann actually) told me about my table pads.Assuming they were referring to the pads, a big skew could result.

Perhaps SS 'learned' the fallacy of statistical QA 'thinking'!:D I hope so. I told Jim that SS needed to rethink the spec if compliance with the spec could lead to a rip fence becoming so far out of alignment when moved from the main table to the extension/floating table that it was "unusable" (his word). He agreed.

Naw, the sample size was too small!:rolleyes:

Wonder what the 'tolerance' is/was! I never got that info out of him.

See my comments above in red.

algale · Post by **algale** » Sun Feb 16, 2014 5:38 pm

dusty wrote:I believe, because I have been told so by Nick, that the pads to which you refer really have a dual purpose. Yes, they are the mounting points for the spacers used to position the rails (front and rear). But they are also the reference points used by the milling machines during manufacture.

As such, much more often than not, if the pads are out-of-spec this will be detected during the manufacturing process. See my response to JPG in this thread: I was not told they were out of spec but at the maximum opposing tolerances (specs) causing the skew. I suspect that if we knew everything there is to know about what happened to your tables, there would be no mystery.

As it is, you are happy because your tables have been made to work properly. However, I am not convinced (and will not be because of my nature), that the situation is as simple as "they barely met specification and therefore needed to be shimmed". Shopsmith knows more than you have been told.I have no reason to suspect Jim McCann was not telling me the truth, the whole truth and nothing but the truth about what he found with the tables. And, frankly, I don't think you have any grounds to insinuate that SS held back relevant information.

See my comments in red.

dusty · Post by **dusty** » Sun Feb 16, 2014 7:27 pm

Shopsmith has done right by you and I understand why you feel the way you do. If I was in your situation, I would probably feel the same way.

But, I am not and I do not. I am skeptical. I worked far too long in manufacturing quality control as a test engineer to believe in coincidence.

Incidentally, I did not say that the pads on your tables were out-of-spec.

"As such, much more often than not, if the pads are out-of-spec this will be detected during the manufacturing process."

algale · Post by **algale** » Sun Feb 16, 2014 8:15 pm

dusty wrote:Shopsmith has done right by you and I understand why you feel the way you do. If I was in your situation, I would probably feel the same way.

But, I am not and I do not. I am skeptical. I worked far too long in manufacturing quality control as a test engineer to believe in coincidence.

Incidentally, I did not say that the pads on your tables were out-of-spec.

"As such, much more often than not, if the pads are out-of-spec this will be detected during the manufacturing process."

I guess I (and possibly JPG) misinterpreted your comment about out of spec pads (and how it would likely be caught during the manufacturing process) as suggesting you doubted that the pads were a viable explanation for the problem I experienced. Now I'm left unsure why you mentioned it at all.

I respect your background as an engineer and your knowledge of Shopsmiths, Dusty, and I assure you that nobody who knows or works with me has ever accused me of lacking a very healthy sense of skepticism. If you had some fact or even a hypothesis in mind that explains why shims solved the problem that is consistent with some other explanation than the one Jim McCann gave me, or if you care to explain what you find to be a "coincidence" or what types of information you suspect Shopsmith is not telling me, I'll consider joining you in your skepticism. Otherwise, I'll be skeptical of your skepticism.

garys · Post by **garys** » Sun Feb 16, 2014 8:28 pm

I suspect something needs alignment. When I got my 510, I went through the alignment instructions for the entire system. When aligned correctly, it works like it should. The fence sits straight across the main, floating, or both tables.
I suggest doing an alignment. Shopsmith has the instructions on their site for you.

JPG · Post by **JPG** » Sun Feb 16, 2014 11:50 pm

algale wrote:I guess I (and possibly JPG) misinterpreted your comment about out of spec pads (and how it would likely be caught during the manufacturing process) as suggesting you doubted that the pads were a viable explanation for the problem I experienced. Now I'm left unsure why you mentioned it at all.

I respect your background as an engineer and your knowledge of Shopsmiths, Dusty, and I assure you that nobody who knows or works with me has ever accused me of lacking a very healthy sense of skepticism. If you had some fact or even a hypothesis in mind that explains why shims solved the problem that is consistent with some other explanation than the one Jim McCann gave me, or if you care to explain what you find to be a "coincidence" or what types of information you suspect Shopsmith is not telling me, I'll consider joining you in your skepticism. Otherwise, I'll be skeptical of your skepticism.

No misunderstanding here.

However each paragraph must be read and understood on its own. Do not connect them when that was not the original intention. Do not overlook the qualifier 'if'.

Lastly a bit of unjustified suspicions voiced, but tis possible.

And SS is under no obligation to open the kimono here!

JPG · Post by **JPG** » Sun Feb 16, 2014 11:54 pm

garys wrote:I suspect something needs alignment. When I got my 510, I went through the alignment instructions for the entire system. When aligned correctly, it works like it should. The fence sits straight across the main, floating, or both tables.
I suggest doing an alignment. Shopsmith has the instructions on their site for you.

Read and absorb this entire thread and those linked to from it. This discussion is not about lack of alignment, rather the inability to accomplish it.

billmayo · Post by **billmayo** » Mon Feb 17, 2014 9:47 am

Before switching to the 520 upgrade, I was mixing early and late 510 table rails when building 510s for sale. I made up a 6" wide 3/4" plywood jig that set on the table and I mounted short connecting tubes extending on each end so I could slide the short jig connecting tubes into the ends of the main, floating and extension table rails. I had to redrill the rail mounting holes in the tables many times and use shims to space the rails the same distance apart and at the same height for all the different tables. I would switch the jig to the other side of table to check and redo as needed. I remember having to use star washers in place of lock washers to hold the rail alignment. I did not remember my customers or me having any alignment problems after doing these changes.