alignment error found?

reible · Post by **reible** » Sun Dec 21, 2008 10:05 pm

Hi,

I brought in one of my extension tables and pulled the rear rail off to measure the hole trying to help someone else and while I held it I noticed something. One end looks nice and square and the other doesn't. Now remember I have never been able to exchange the extension table from side to side as it would never align. I purchased a second one so I have a left side and right side. Nick claimed he could do it despite the shopsmith manual saying it couldn't be done. I may have to change my mind on this if I find different after replacing this rear rail.

So what do you think? I think this could be a problem.

[ATTACH]2589[/ATTACH]

[ATTACH]2590[/ATTACH]

[ATTACH]2591[/ATTACH]

To bad I'll have to wait until spring to find out.

Ed

fixit · Post by **fixit** » Sun Dec 21, 2008 10:15 pm

Ed,

I think you may have hit on the problem. I'm heading for the shop as soon as I get done here to check and see if my rails have the same non-square configuration. Like you, I have never been able to align my SS so the ext. table would work on both ends of the machine.

I'll post back with results of my inspection.

Just checked. The rails on my machine are nearly perfect 90 degrees. I can see a bit of light between the rail and square on one side but not enough to cause a problem, in my opinion, and certainly not as far out as your picture.

P.S. I aligned the main and ext. table (mounted on the right side) on my machine about two weeks ago and I'm within 0.002". Tomorrow I'll check and see if the ext table will align on the left side.

doug45601 · Post by **doug45601** » Mon Dec 22, 2008 12:52 am

Several years back when I ordered and received my 520 upgrade setup I also noticed the same warped issue.. Called Shopsmith, explained to them the problem and they sent me a new piece. I still am unable to get both extention tables to line with the main table..

Watched Nicks instructions over and over and went through the micro-tune up over and over and still to this day can only get close.

Good luck with yours..

dusty · Post by **dusty** » Mon Dec 22, 2008 5:51 am

If you are having difficulty aligning the extension tables to the main table, a malformed rail like reible's could certainly be the cause.

However, after you check your rails, check the extension tubes that you are using. They too must be straight for the alignment to work as smoothly as Nick demonstrated.

I have two sets of tubes that are not straight enough for that demo. Well, I had two sets of 5' tubes. Now I have only one. I cut the original two tubes into smaller pieces.

It does not seem to me that this could be anything other than a manufactured condition. I don't think that an aluminum extrusion could be bent that way.

Ed, does that condition appear to exist for the entire length of the extrusion?

reible · Post by **reible** » Mon Dec 22, 2008 11:32 am

Hi Dusty,

I don't have a really good way to measure but if I use the bottom as a reference I would say it tapers to nothing at about 2/3 the way to the other end. The pem fastener gets in the way so it could be I messed up when I moved the square over it???

I'm beginning to think maybe this is not going to help much but I'll replace it anyway just to be sure. As was mentioned by doug45601 he had his replaced and alignment is still an issue.

It was late last night so I was not thinking as clear as I am this morning. I checked the other end for square using the square area where the tube goes. It reads 1.330 on both diagonals. The other end that is "warped" is 1.289 by 1.341. The tube however rides against only the top small rounded area in the extrusion, this limits the effect of the problem.

The defect is not what you would expect to see in a extruded part so it was damaged after it was made. Maybe even I did it at some point in time or maybe it is the part that was next to doug45601's piece when they were cut out??? Anyway it is to late to blame shopsmith as if it had been defective I should have noticed it at delivery.... heck it could have even been done on the truck???

I worked one summer while at school at an aluminum extrusion company as a "draftsman". They were surprised I actually knew how to measure things and could help out in that area as well (all due to working in a machine shop before I was drafted). So that combined with me being in school I got to do a lot more then just drafting and they made it an educational experience for me. It was a nice outreach from the company/people there and I hope their experience with hiring students went well and they continued doing it. Anyway I digress...

Ed

dusty wrote:If you are having difficulty aligning the extension tables to the main table, a malformed rail like reible's could certainly be the cause.

However, after you check your rails, check the extension tubes that you are using. They too must be straight for the alignment to work as smoothly as Nick demonstrated.

I have two sets of tubes that are not straight enough for that demo. Well, I had two sets of 5' tubes. Now I have only one. I cut the original two tubes into smaller pieces.

It does not seem to me that this could be anything other than a manufactured condition. I don't think that an aluminum extrusion could be bent that way.

Ed, does that condition appear to exist for the entire length of the extrusion?

dusty · Post by **dusty** » Mon Dec 22, 2008 7:01 pm

reible wrote:Hi Dusty,

........
It reads 1.330 on both diagonals. The other end that is "warped" is 1.289 by 1.341. The tube however rides against only the top small rounded area in the extrusion, this limits the effect of the problem.
.........
Ed

My time was demanded elsewhere today so I didn't get as much time in the shop as I would have liked. I did get enough time out there to conclude that two of my rear rails are reasonably square (by diagonal measurement).

My readings were a bit different than reible's. I have one whose diagonals measure 1.248/1.246 and another that measures 1.300/1.297.

I eye balled four front rails (with the aid of an engineer's square) and feel they are good.

I think I have to go get a better caliper. I have a really good one but it is calibrated in mm. The other one is a plastic one that I bought (I think from Shopsmith). It has seen better days. The local Woodcraft is having a local sale - maybe I'll get lucky.

I can use my 0 interest American Express card there and SWMBO makes certain that it gets paid in full every month.