Aligning Extension Tables

[dusty]

I decided today that it was time to sort of reorganize the shop and make ready for the next big build cycle. The family is growing (grand children and great grandchilden) faster than one woodworker can keep up with. There are projects galore so I had to get the Shopsmith back in tune.

I messed with the main table alignment a while ago so I knew that was good. That was my starting point.

After rearranging equipment and rolling the SS all over the shop, it ended up right back where it was. Except that I took it down off the blocks that I had it on. The blocks were being used to level the SS end for end and infeed to outfeed. Without blocks, it is level from end to end. But b ecause the garage floor slopes (for drainage) the Shopsmith is also not level (infeed to outfeed). I'm going to leave it that way at least for a while because it is more stable sitting directly on the floor.

All that is left are the extension tables. These should be easy but they sure are not. No, they are easy if one is content with having a right hand extension table and a left hand extension table and never swapping them.

That would be too, too easy. I want to understand why they cannot be freely swapped back and forth without adversely effecting their alignment.

[charlese]

Now You've got me trying to decide if I am just gross, or am I sloppy, or lackadaisical, or is my Mark V able to compensate for my wavy, concrete floor? I aligned the machine up some time ago and I move it all around in my shop. Have used it at oblique and right angles (even 180 degrees) to where it normally sits and it saws and does other operations just fine. My concern, and reason for moving the Mark V is to have adequate in-feed and out-feed room for the work piece.

I have noticed that my one extension table is not perfectly level with the main table in some locations, but this has never been a problem. After all it is mostly used for support. If, for example, if the in-feed side is 3/16" lower than the out-feed side, who cares? The support is there! If I were to use a floating table for the rip fence, tightening the front of the table around the extension tubes gives me a rip fence that is as precisely parallel to the saw blade as if it were on the main table. This has always seemed to work for me. If pieces come out square, in all dimensions, and are the correct size, I guess I just don't care if tables aren't perfectly aligned, or if the Mark V itself is level or canted a bit.

All I really care about is the main table stays in perfect alignment with the saw blade - and in drill press configuration, the table sits in a plane perpendicular to the drill or router bit. My sweet Mark V 510 has always competently answered that demand!:D

If I were to take the unit outside and set it up on gravel or dirt, then I might have to look at the potential racking of the overall machine. But there's no need to do that! The hand held "Skill saw" handles any outside stuff.

[greitz]

Hi, Dusty- I admire your enthusiasm! I know that every time I "reorganize", it'll be months before I remember where the new location is for everything, so I put that chore off as long as possible.

Anyway, if the miter slot is racked a few thousandths away from perfectly parallel to the blade, then the whole main table is also a few thousandths away from parallel. If you then align the extension table parallel to the main table, on the right, it will also be a few thousandths away from parallel to the blade. When you move the extension table to the left side, the extension table will still be parallel to the main table, but the tubes will not line up (nor will the front and back of the table). An error of a few thousandths at the miter slot distance (a couple of inches) can translate to a much bigger error when the extension table may be several feet from the blade.

Maybe someone with better computer skills than mine can make a drawing?

Gary

[Randy]

I moved a few months ago and have just started setting up the shop. My 510 sat in my semi-level basement for 18 years and I was never able to get the extension table perfect. I would have had to put cleats on the floor to put it back in the same spot every time. So I lived with the difference close but not within NASA spec's.

Now in my new garage I mean shop the floor is even worse. So I may have to mark the floor. Now I'm sure I'm not even up to Ford's spec's!

[dusty]

charlese, I believe you are reading something into my frustration that is just not the case. I don't challenge your position that the Shopsmith does it work just fine and that it performs to normal and reasonable expectations even after being moved around. If you can roll it out in the gravel driveway, it'll probably work there too.

What I want to understand is why the left and right extension tables are not interchangeable without alignment being adversely effected. If my machine was being racked, there would be no question. It is not. The floor is quite level side to side and it slopes evenly toward the garage door just as you would expect.

The tubes, all four of them, are reasonably level side to side (.1 to .2 degrees using a Wixey). If the tubes are in fact all parallel to one another then the extension tables should not be position sensitive but they are. WHY?.

I am attempting to understand why they cannot be moved without being effected.

Incidently, main table alignment to the blade and to the miter slot is not part of my frustration at all. They remain perfectly acceptable through normal use and abuse.

Extension tables - that is all and if I leave them where they were aligned they remain acceptable - especially to the standards that you expressed in this thread.

[Nick]

Dusty, check that your extension tubes are parallel to the table surfaces and the way tubes (vertically) with the Wixey inclinometer, since you have one. Also check that they are parallel to each other.

Insert the tubes in the main table, tighten the locking knobs, and take a reading on each tube with your Wixey balanced atop the tubes. Also take a reading on the main table surface with the Wixey parallel to the direction of the tubes. Do the same for the way tubes. All readings should be the same, within a few tenths of a degree of one another.

Now insert the tubes in one of your extension tables and take the same reading (knobs locked) -- way tubes and extension table surface. In order for you to be able to swap an extension table from side to side, all these readings should be very, very close to one another. That is, the table surfaces should parallel to one another when locked in place. The extension tubes should be held parallel to one another and to the table surfaces. And everything should be parallel to the way tubes.

With all good wishes,

[a1gutterman]

Hi Dusty,

I know that this problem has haunted you for a very long time: You have mentioned it on this forum several times. Maybe you could try this (maybe you already have):

I know that you have more then one main table. You could remove your #1 main table from it's position and replace it with #2 main table. Do a complete alignment with this "new" table including the extension tables. Now try switching the extension tables. Do you still have the same problem?

If no, perhaps your #1 main table is somehow tweaked?

If yes, at least you know you and your SS are consistant:D .

[Ed in Tampa]

Dusty
When I initially set up my Mark V 500 my extension table was exactly perfect when used in either side. When I upgraded to the 510 and then later to the 520 I have never been able to achieve that perfection. Right now it is the closest I can get it. The extension table is perfectly aligned with main table when used on either side however when I place it in right side the legs slide freely up and down in the tube guide. However when the table is moved to the left side there is a bind. I have worked and worked on removing that bind and so far I have been unable to accomplish it. The minute I allow the aux table to move out of alignment with the main table the bind disappears.

Everyone convinced me that is normal and that I should simply get another aux table, using one table on the left and the other on the right. However I still can't figure out why I can't get the table to align with the main table when placed on either side and not bind in the support tube.

I still believe the manufacturing quality of the 510 and 520 upgrade was not as quality as the original 500. I'm still very dissatisfied with my main table, even after SS replaced it twice it still has warps and dips in it, that to me should not be.

My model 500 was a model of manufacturing excellence the two subsequent upgrades don't seem to have that same quality.
Ed

[Nick]

Funny thing, Ed. I've got a 500 that performs exactly the same way as your 520, and a 520 that performs like your 500. On my 500, the auxilary table binds on one side, but aux table fits like a dream on both sides of my 520. Your observation about a loss of quality seems unlikely since Shopsmith uses the same materials and manufacturing procedures to manufacture the 520 as they used for the 500.

The old Mark V 500 "mini" that I use for sharpening also has this problem, by the way -- the aux table binds in one side but not the other. The folks in the factory speculated that either the base or the headrest (or both) castings were warped. This can happen if the castings are machined "green," before they have been properly seasoned. Castings need to rest for a few months, just like lumber. It can also happen if one the bench tubes is bowed. Normally, bowed bench tubes are weeded out in assembly, but there is a possibility that a tube could have been bent in shipping or another incident after it was assembled.

You say you "upgraded," Ed. Does that mean that the frame (castings and bench tubes, specifically) of your 520 is the same as your old 500? I want to check some things with my factory snitches before I comment further.

With all good wishes,

[billmayo]

I welded a Mini metal chuck on the 5/8" arbor and use it to turn the way and bench tubes to clean, remove rust and polish them. I added two wheels to the lathe tailstock to support the tubes. I am finding a lot of the tubes have a slight bow in them which I believe would affect alignment. The several problems I could determine was when the Shopsmith was being converted from the drill press mode, the headstock and way tubes were dropped onto the headrest. Also loading and unload the Shopsmith on/off a trailer/truck with the headstock located in the middle of the way tubes. I recomment always putting the headstock at the headrest end when moving or converting to the drill press mode. Another good reason for installing the Lift-Assist package.

Bill Mayo