Older 510 main table not aligned to new table extensions?

[pennview]

I just took a look at my 510 and see that the table surfaces are not on the same plane. I didn't measure the misalignment, but I guess it was about the same 2mm seen by cobalt60. I loosened the four nuts that secure the tubes to the table to see if there was sufficient slop in the assemblies to allow a fix for the misalignment, but there isn't enough. So, I'm thinking that a simple fix would be to bore the holes in the table a bit oversize so that I could raise the table by lowering where the tubes attach to the table.

[dusty]

WAIT, don't bore holes yet. The solution might be a lot simpler and already anticipated in the design. I am confident that the issue is not related to a major design deficiency by Shopsmith but rather a lack of applied procedures by we owners.

I have not heard anyone say that they have loosened the nuts on the bottom of the "extension/floating tables" to correct the height issue that we are talking about.

Whenever I have extension/floating tables to align I discard all instructions in the manual and use my own procedure.

AFTER COMPLETING Main Table alignment, I install extension tubes into the front and rear Main Table rails and tighten the knurled knobs.

I then loosen ALL of the nuts on the floating/extension tables in question. Then I slide the extension or floating tables, one at a time, onto the extension tubes and now alignment begins.

Tighten the knurl knobs on the floating/extension table - with the table snugged up tight against the side of the Main Table. This basically results in the tables being parallel to one another.

I then clamp a straight edge to the top of the Main Table (I use my long level for this). Now I clamp the floating/extension table up to the bottom of the level and lighten all of the nuts.

The tables were parallel to and on the same plane as a result of being clamped to the level and to one another. The nuts were loose until this was done and all that you are doing is securing the nuts with the tables in that perfect position.

This was verbose but I hope it is understandable and that it works for you 510 users. In my opinion, it is a tried and tested method.

There is no design defect in the 510 system. Yes, the 520 is an improvement unless you have a deformed rail or a bent tube.

[cobalt60]

Hi dusty, I tried that exact procedure over my lunch break. Well, only on one side, since the far-side-middle bolt of the main table is like RIGHT up against the metal angle indicator thingy. huh.

Anyway, I did a half-assed version of this, and the result was the main and extension tables perfectly parallel, but both extension tables still equally lower than the main (about 2mm).

I'll try again tonight, this time with conviction (and a straightedge and clamps, etc.)

dusty, if you have a moment, can you do me this favor: Can you measure the inside radii of the main table tube and the extension table tube? Mine are as follows:

Outside diameter of both: 32mm

Inside diameter of extensions: 27.4mm
Tube wall thickness of extensions: 3.0mm

Inside diameter of main table: 26mm
Tube wall thickness of main table: 2.6 mm

Table-top to top of bolt-holes are the same across all tables. When roughly set-up, the extension tables are consistently 2/64" lower than the main, though perfectly aligned in all other directions.





All this makes me wonder: IF (and only if) there is an updated version of the main table tubes, and that new version is the same inside-diameter as my extension tables, and I order these tubes... Problem should be solved... right? Frankly, I'd much rather spend a few bucks to do this than bore holes (see my earlier note about fearing metalwork).



EDIT (thanks JPG40504): I mistakenly swapped the ID measurements -- Main table is the thinner walls, and thus the larger inside diameter. Apologies, didn't mean to introduce more confusion.

[Ed in Tampa]

I think this problem is inherrant to all 510 and I believe that is reason the 520 was designed to replace the 510.
The problem is not different tube sizes but rather the way the connector tube in secured in the table fence tube.

The tube have to have some slop but if the connector tube is pressed against the top of the fence tube on one table and against the bottom of the fence tube on another. there will be a difference in table heights even if the table fence tubes are at identical height to the table surface. The only way alignment will work is if you place each the connector tube in each table exactly the same way each time.

Something I tried to do repeatedly with my 510 only to see it change as vibration or me bumping the table caused the connector tube to slide up or down in the table fence tube.

The problem is the knurled nuts that locks the connector tube in table fence tubes comes in from the side. If you lift the tube and insure the stud touches the connector tube below the apex of the arc on that side the tube will stay but in most cases the stud hits the arc and there is very little actual surface contact so very little pressure is needed for the connector tube to drop down.

Again tube size is not the problem nor is the tube wall thickness. The problem is the concept. If you have every fence tube mounted to the table so the top of the tube is the same distance from the top of the table on each table (which is exaclty how the 530 is aligned) those tubes are aligned, the problem is the connector tube once in the fence tube and secured may be pressed against the bottom inside of the fence connector tube on one table and againt the top on the next. The locking stud and how it contact the curvature of the connector tube determines which way it will push the connector tube and since the tube is fixed in place by the previous table the newly installed table moves up or down.

Is this a problem? It drove me absolutely crazy the whole time I had the 510, but I will have to admit I never was able to prove this difference in table heights caused a safety or accuracy problem. Remember we are only talking the smallest difference.

The problem is totally solved by the 520 design. The studs that secure the connector tube in the table fence tube push the connector up against the top of the fence tube when tigthened. To insure all tables are in the same plane all one has to do is insure each table fence tube top is the same distance from the top of the table on each table. If they are when you tighten the connector tube it is pushed to the top of the fence tube and forms the plane for the next table which will push the connector tube to the top of it fence tube.
Thus perfect alignment.

Dusty has a great idea but again the problem is really where the tightening stud contacts the connector tube. If the stud contacts it above the apex of curve on the side it will force the connector tube toward the bottom of the fence tube. If it contacts it in middle there is so little contact the table will move due to vibration. If it contacts it from the belown the apex of the curve on the side it will force the tube up. It is a design flaw that happened. Does it render the SS useless no but it can really bug you, I know.

[dusty]

I have taken some measurements and I conclude that my ODs are very similar to yours but my IDs and consequently wall thickness is considerably different.

I am really not alarmed by this at all because there are really NO CRITICAL DIMENSIONS involved in this discussion except for the physical relationship of the front rails. The ideal setup would have the front rails perfectly aligned one to another throughout a setup.

I took measurements at opposite ends of each rail both OD and ID. The wall thickness shown here is calculated (not measured). A couple numbers look odd and tomorrow I will measure those thicknesses for clarification.

Main Table
Front Rail OD 31.90mm 31.85mm Front Rail ID 27.20mm 26.95mm
Rear Rail OD 32.60mm 32.55 Rear Rail ID 27.20mm 27.05mm

Left Extension
Front Rail OD 31.80mm 32.65mm Front Rail ID 27.25mm 27.35mm
Rear Rail OD 32.30mm 31.95mm Rear Rail ID 26.85mm 27.35

Right Extension
Front Rail OD 32.15mm 32.45mm Front Rail ID 27.30mm 26.90mm
Rear Rail OD 31.65mm 32.05mm Rear Rail ID 26.80mm 26.90mm

Main Table
Front Rail Thickness 4.7mm 4.9mm
Rear Rail Thickness 5.4mm 5.5mm

Left Extension
Front Rail Thickness 4.6mm 5.3mm
Rear Rail Thickness 5.4mm 4.6mm

Left Extension
Front Rail Thickness 4.85mm 5.55mm
Rear Rail Thickness 4.85mm 5.15mm

[cobalt60]

I am really not alarmed by this at all because there are really NO CRITICAL DIMENSIONS involved in this discussion except for the physical relationship of the front rails. The ideal setup would have the front rails perfectly aligned one to another throughout a setup.

Thanks so much for going through the trouble dusty. I'm honestly starting to think that SOMEHOW my main table rail is simply different than the others, and if it were the same, I wouldn't have the trouble I do right now. Basically, gravity is NOT pulling the main table down (fixed to the frame), so the extension tube is resting on the BOTTOM of the inside-diameter of the main table, but conversely, the TOP of the inside-diameter of the extension tables. The greater the variation of these inside-diameters, the greater the potential table height variance.


However, I'm going to try a more-high-precision setup tonight and report on the results once I have them.


Separately, I'll probably call customer service tomorrow to ask if I could order that tube part, and if it's OK to return the items if they don't solve the problem.


Thanks again to everyone for your thoughts. I'll be back soon!

[JPG]

I have measured 4 510 rails from my 'collection'.

2 are of the older mouse hole/bolted into tapped holes in the tables.

2 are of the newer studed, secured with nuts version.

1 of each being a main table rail and 1 each an extension table rail.

The rails measured as follows:

ALL had an od of 1.25 " = 31.75mm

The older had an id of ~ 1.02" = 25.9mm and a wall thickness of ~.112" =2.8mm.

The newer had an id of ~ 1.065 = 27mm and a wall thickness of ~ .088" = 2.2mm.

I am confused by Cobalt60 stating the tubes are 'loose' in his main table rails, yet he measured them to have a smaller id?? The 'extension' tables were lower than the main table. Both statements seem backwards from his measurements.

His measurements confirm to me that the different size rails are not a case of 'old/new' style, but that there are new style with either size rails(wall thickness). His measurement of 'all' newer version rails are consistent with and vary by the same amount as my 'old/new' set.

I think Ed nailed it. The tubes are free to slide up or down from a contact point opposite the thumbscrew and would introduce a vertical variation. The newer rails(larger id) may have been an attempt to both force the tubes more positively(up or down unfortunately) so as to reduce the drift Ed described. I think it made ss realize a different approach was needed since the 'fix' was worse than the original problem.

Previously was discussed the front to rear alignment problem Keakap had with his 'mixture' of old/new rails. The id difference was identified then, but the vertical 'issue' was not recognized at that time(or at least not discussed).

Much of this is conjecture since we do not have a sufficient sample to establish the time line. It is quite possible the rail wall thickness was 'accidental' due to some totally independent set of circumstances(differing vendors...)

The 'problem' can be 'worked around' with an extension table by adjusting the support tube position, but the 'floating' tables are left to seek their own 'floating positions vertically'(maybe that is what got them their 'name'!).

In the case of the main/ext table setup. the tubes probably end up dropping below the 'center position' and if the rails are of the same id, then the table tops should align closely. With the floating table(s) positioned between the main and extension table, since the tube is supporting the table(the opposite of the main ext table example above), the tube will align with the rail above the 'center line'. Thus the table tops will vary by the difference between the rail id and the tube od(1"). This difference will be greater with 'newer' rails, and will vary if a mix of old/new rails are being used. None of that is good and will cause frustration(just ask Ed and Keakap).

If you have a rail dimension 'mixture' consistency will be elusive.

If you have a set of consistently sized rails, accommodation of the 'supporting/supported' scenario must be allowed for.(either always pull the tube up when tightening the main table or extension tables to the tube,
or always pull the tube down when tightening the floating table(s) to the tube.

[cobalt60]

Whoops, edited in my mistake. Yes, I swapped the inside diameter measurements -- the main table has the extra room. Apologies for adding confusion here!


Here's the results of trying much harder to force the tables into alignment:

Laid the tables flat on my bench, loosened ALL bolts, inserted tubes and tightened everything up.

[ATTACH]11517[/ATTACH]

[ATTACH]11516[/ATTACH]


Dropped it back in and ... results?

[ATTACH]11518[/ATTACH]


[ATTACH]11519[/ATTACH]

Welp, not great.

[ATTACH]11520[/ATTACH]




It's closer than before, maybe 1/64" instead of 2/64". But it's NOT OVER YET. (I'm just out of photos for this post)

[cobalt60]

OK, I'm not giving up. I'm sure now that the amount of vertical play is equal or greater than the offset. So I just need to try harder, right?

Here's me holding the table in place by hand, thumbscrews totally loose:

[ATTACH]11521[/ATTACH]

And here's a pretty-good job of hand-alignment with everything tight:
[ATTACH]11522[/ATTACH]

OK but honestly that seems VERY fiddly, to the point where it just doesn't seem "right." I wonder how it holds up to some basic work.

[ATTACH]11524[/ATTACH]

[ATTACH]11523[/ATTACH]


It seems to stay put after some basic pushing around and jostling. I guess I can deal with fiddly setup if necessary, but it's not ideal.

Honestly, I can't help wonder if things would just work better if I had matching tube diameters. Let me know if this sounds silly: I think I'll call SS Customer Service and see if I can buy two replacement main table tubes -- with the express intent to return them if they don't improve the situation.





...

But it's NOT OVER YET.

[pennview]

In looking at the misalignment of the tables on my 510, I tried to adjust the studs and nuts that hold the tubes to the floating table, but found virtually no room for adjusting the table height because the diameter of the holes in the table are a pretty good match for the diameter of the studs. As I recall they are about 1/4" diameter.

I'll take another look tomorrow and try Dusty's method of alignment. If that doesn't work, I'll just drill out the holes 1/64" larger at a time until I can get the tables on the same plane. If I screw one up, there's always JBWeld.