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Re: Truing, As Best You Can, Shopsmith Table Tops
Posted: Fri Sep 11, 2015 6:50 pm
by dusty
I believe you are setting the tilt of the Extension Tables to equal the tilt of the Main Table which I suggest is not perfectly level.
When you align the way you did using a straight edge and the Main Table set for what you believe to be 90.0° to the blade, you actually transpose to the Extension Table ANY tilt that there might be in the Main Table.
If the tilt angle of the Extension Table was only .1°, the unwanted rise that would occur 62" away (at the far end of the Shopsmith) would be 3/16". If you was using a straight edge to align that second Extension Table, the left hand side of that table would be 3/16" higher than the right hand side of the other Extension Table. At the same time, back at the first Extension Table, the left hand side of that Extension Table is only 1/64" higher than the right hand side.
Now the numbers are not the same for what you did because when you align the second table, you side the Headstock to the left (closer to the left hand Extension Table). Doing this reduces the amount of error that is transposed to the second Extension Table but there is still some error.
I think this is what you are chasing right now.
BTW if you go shopping for an angle indicator look around. There are a couple others besides the Wixey that you might want to consider. The Angle Cube (iGaging) is one of them. Even the new Wixey is different than the one I have. Mine has a Resolution of 1/10° and an Accuracy of 1/5° while the new one has the same Resolution but an accuracy of 1/10°.
Re: Truing, As Best You Can, Shopsmith Table Tops
Posted: Fri Sep 11, 2015 8:14 pm
by JPG
dusty wrote:jsburger wrote:Ed in Tampa wrote:I hope when this thread is completed someone will summarize the information.
For what it is worth I can switch my Aux table from the left to right and have the tubes line up on my 520. I aligned it as Nick taught us back in a saw dust session.
If you are talking about the connector tubes between the tables then yes. They will almost always fit since the hole in the rails is slightly larger than the tube and the tubes are not perfectly straight so you can rotate them to start them in the rail.
We are talking about putting a straight edge on the table tops and having them co-planer from end to end when you switch ends without any external forces.
In this case I think the discussion is more about figuring out the mechanics and the geometry of what is going on rather than saying the accuracy of the SS is inadequate. I think we can all agree that the SS accuracy is perfectly adequate regardless of this discussion.
If you use stop collars on the Extension Tables, you may be having the same experience that I did yesterday.
I aligned the Extension Table to the Main Table with the Headstock moved all the way to the right and with connector tubes inserted into the rails. Everything looked good so I tightened the nuts that secure the Extension Table to the Extension Table Base (504273). With that done, I moved the Extension Table to the other end, slide the Headstock and Carriage to the left and checked for level (coplanar table tops).
No cigar.
The Extension Table was about 1/2" - 3/4" too high. Back to the other end with the Extension Table. It checks out fine. Tables check level with the Wixey. A straight edge across the tables looks good. The stop collar is tight in the correct location. Confused! I move the Extension Table back to the left side and recheck. Same problem. Still confused, I decided to go to bed.
Started the next day with the same results. Nope, this has got to be operator error. Everything checks and that can't be. Something does not check. Got that, John.
OPERATOR ERROR. It has to be.
Break the entire system down and start over.
The very first thing you need to do is validate the tables and then square the Main Table to the blade. Do this meticulously. It is absolutely imperative that the Main Table be square to the blade (no tilt) and that the miter tracks be parallel to the blade (no skew).
Next I would mount an Extension Table in the right hand side and loosen all four of the nuts securing the table. Make the table loose enough to move around. Set it for a height that approximates that of the Main Table. Side the Carriage to the right so that the right edge of the Main Table almost touched the left hand side of the Extension Table. Slide the front extension tube into the rails of both the extension table and the main table. Tighten the thumb screws on the rails. Now do the same with the rear side. At this point, the tables should be co-planar as this is established by the rails and the extension tubes. All that needs to be done is to position the Extension Table Base vertically (if it is not already there) and secures all of the nuts and bolts that hold the Extension Table. I now use a stop collar on the Extension Table Bases to establish this height. John taught me that during this thread.
If this has been done correctly, you can move this Extension Table to the left side, slide the Headstock and Carriage to the left and insert the Extension Tubes. The Extension Tubes should slide FREELY into the rails. If there is ANY binding, something is not correct.
All that is left to do is another Extension Table for the other end. If this went well, the Extension Tables can be used at either end. Some minor tweaking may be needed depending on how picky you are.
Start with the Main Table total alignment and end with a verification that that alignment is still dead on.
Yes, you need to loosen the stop collars before you attempt to make any table height adjustments.
JSBURGER:
I did it that way twice yesterday with the same results. Since I have two extension tables I aligned one on the right and the other one on the left. All three tables were dead on and co-planer with the straight edge, square to the blade and miter tracks. Then I swapped the tables end for end. The left hand table was tilted to the right compared to the main table. The right hand edge was below the straight edge about 1/16" both front and back. The right hand table had about the same tilt to the left
BUT the really weird part was that when the front of the right hand table was at the same height as the main table the back of the table was about 1/8" low. That makes absolutely no sense to me. Nothing on that machine is that far out to cause that.
I did the alignment twice. The second time I loosened all the aux table nuts completely and ran them up so the tables sat close to the brackets with just two threads showing above the top nuts to make room for adjustment. Exactly the same result. Really confused since they were not that way when I first started down this road.
Wixey is on the way and will be here Monday. Then we will start over again.
JPG:
Bent tubes on the mounts????
Re: Truing, As Best You Can, Shopsmith Table Tops
Posted: Sat Sep 12, 2015 5:59 am
by dusty
Bent tubes on the mounts????
I assume you are referring to extension tubes and not the the vertical support tubes. The extension tubes would have to be bent quit severely to cause a real problem. The Extension Tables are actually floating when being aligned to the straight edge. But if you suspect bent tubes, take them out of the equation. Just don't tighten the thumb screws; this would negate the effect of bent tubes.
Re: Truing, As Best You Can, Shopsmith Table Tops
Posted: Sat Sep 12, 2015 12:21 pm
by JPG
dusty wrote:Bent tubes on the mounts????
I assume you are referring to extension tubes and not the the vertical support tubes. The extension tubes would have to be bent quit severely to cause a real problem. The Extension Tables are actually floating when being aligned to the straight edge. But if you suspect bent tubes, take them out of the equation. Just don't tighten the thumb screws; this would negate the effect of bent tubes.
Assumption wrong.
How can the tables align differently(but not opposite and equally) if all four mounting tubes are straight?
As an aside, I understand the rationale for using the rails/tubes, but they introduce an additional factor. Especially with the newer(late 510 and 520 rails being adjustable).
IIWM, I would align the tables first, then address rail compatibility issues. However my 510 is of the earlier version(rails not meaningfully adjustable)(and some think them too damn inaccurate anyway!
).
Re: Truing, As Best You Can, Shopsmith Table Tops
Posted: Sat Sep 12, 2015 12:37 pm
by rjent
I know this is probably a dumb question. But here goes.....
I always check for square on the blade before making cuts, always. And if I use the extension tables, I always use the proverbial long level to make sure they are square and flat, this is even on the 10ER.
What am I missing? What is so complicated here? Is this whole exercise about repeatability? Accuracy?
Just asking. Just trying to learn .....
Re: Truing, As Best You Can, Shopsmith Table Tops
Posted: Sat Sep 12, 2015 1:39 pm
by dusty
JPG wrote:dusty wrote:Bent tubes on the mounts????
I assume you are referring to extension tubes and not the the vertical support tubes. The extension tubes would have to be bent quit severely to cause a real problem. The Extension Tables are actually floating when being aligned to the straight edge. But if you suspect bent tubes, take them out of the equation. Just don't tighten the thumb screws; this would negate the effect of bent tubes.
Assumption wrong.
How can the tables align differently(but not opposite and equally) if all four mounting tubes are straight?
As an aside, I understand the rationale for using the rails/tubes, but they introduce an additional factor. Especially with the newer(late 510 and 520 rails being adjustable).
IIWM, I would align the tables first, then address rail compatibility issues. However my 510 is of the earlier version(rails not meaningfully adjustable)(and some think them too damn inaccurate anyway!
).
If the Extension Table(s) slide up and down in the Base Arm, it is doubtful that the Extension Table legs are bent.
The rails move a little but I would not call them adjustable.
Re: Truing, As Best You Can, Shopsmith Table Tops
Posted: Sat Sep 12, 2015 1:45 pm
by dusty
rjent wrote:I know this is probably a dumb question. But here goes.....
I always check for square on the blade before making cuts, always. And if I use the extension tables, I always use the proverbial long level to make sure they are square and flat, this is even on the 10ER.
What am I missing? What is so complicated here? Is this whole exercise about repeatability? Accuracy?
Just asking. Just trying to learn .....
There is NO issue if you are using a Main Table and and one Extension Table.
There is no issue if you are using the Main Table and two Extension Tables so long as the Extension Tables were aligned where they are being used.
The problem does not occur (or become noticeable) until you try to swap the Extension Tables end for end (UNLESS there is a defective (bent) part somewhere that we are not considering).
The most likely suspect for that, in my humble opinion, would be a warped table and I would think a table as bad as we are talking about would be very noticeable.
Re: Truing, As Best You Can, Shopsmith Table Tops
Posted: Sat Sep 12, 2015 2:57 pm
by JPG
dusty wrote:JPG wrote:dusty wrote:Bent tubes on the mounts????
I assume you are referring to extension tubes and not the the vertical support tubes. The extension tubes would have to be bent quit severely to cause a real problem. The Extension Tables are actually floating when being aligned to the straight edge. But if you suspect bent tubes, take them out of the equation. Just don't tighten the thumb screws; this would negate the effect of bent tubes.
Assumption wrong.
How can the tables align differently(but not opposite and equally) if all four mounting tubes are straight?
As an aside, I understand the rationale for using the rails/tubes, but they introduce an additional factor. Especially with the newer(late 510 and 520 rails being adjustable).
IIWM, I would align the tables first, then address rail compatibility issues. However my 510 is of the earlier version(rails not meaningfully adjustable)(and some think them too damn inaccurate anyway!
).
If the Extension Table(s) slide up and down in the Base Arm, it is doubtful that the Extension Table legs are bent.
The rails move a little but I would not call them adjustable.
The rails are 'adjustable' to the extent of the slop in the mounting holes etc.. The original 510 had tapped holes in the table which were definitely non-adjustable. The 520 comes with that 'gauge'.
Not all the extension tables that I have slide 'smoothly' in the spt mounts. I attribute the drag to be caused by less than perfect alignment/straightness.
Not having used the 510 much with the tubes, I think in terms of 'no tubes' like the M5 and do not routinely think of using the extension tubes for 'aligning'.
I am really coming up blank with a reason for Jsburger's slanting ext table(left vs right). Like Dusty, I do not like to consider a manufacturing error(bore alignments).
Re: Truing, As Best You Can, Shopsmith Table Tops
Posted: Sat Sep 12, 2015 3:15 pm
by dusty
I have used it but no longer. The primary purpose of the gauge was to get the tubes on all the tables to line up with one another so that the extension tubes would go through. I simply mount the rails loosely, turn the tables up side down on the work bench side by side, slide the 5' tube into the rails, tighten all the thumb screws and then secure the rails to the tables. Perfect alignment
Re: Truing, As Best You Can, Shopsmith Table Tops
Posted: Sat Sep 12, 2015 7:54 pm
by reible
This was an interesting read.
My own history was that when I got my 520 I could align a table on one side but it would not work on the other end. By that I mean if I wanted to use it for just support it worked fine but if I wanted to use the rip fence on it that was a different story.
When I read the manual it indicted that this would be the case, the design intent or practicality that resulted lead me to purchase a second table to use on the "other" side.
When I got my second upgrade to a 520 I also got a second extension table for the same reason. I could get things close and the tubes would even fit but I would not or shall I say could not use it for ripping.
Since the 5 foot tubes are easy to bend and there is a lot of movement possible just having the tubes fitting ie sliding in does not mean it is adjusted.
The first change I had to this situation was when I upgraded to the double tilt. After the upgrade I found I could take one extension table and use it on both ends and have it close enough to use the rip fence on either table and be with in tolerance. Now I have not repeated this test since then so it is quite possible that it is now totally out of wack and I just got lucky that one time.
The method of measurement I selected was a long tube which would be placed between a tooth on a blade and the rip fence. The tube was the longest reach I had and by inserting a feeler gauge I could get a reading of how square the fence was to the blade at the longer distance. By repeating this on both sides after alignment my goal was to have no more then a .005" difference in squareness to the blade. In the previous attempts before the double tilt I was seeing numbers in excess of a 1/32" and sometimes almost an 1/8".
So far as tables being less then flat or combinations of other errors they might be there but I've not seen them to be a problem. I use a drywall square to do table to table alignment, the 4 foot length means that I can not span all three tables but main to right then main to left has worked for me. The long part of the T provides weight so I can use the edge of the rule to look for gaps which I like as a gauge.
Looking forward to more reading on the subject.
Ed