I have noticed on the newer Shopsmiths the main table is not ribbed between the two mitre slots. Does anyone know why Shopsmith stop ribbing the table completely?
When I bough mine SS would use the table ribbing as a selling point. Less surface contact so the wood moved easier and smoother.
I ask because I wonder if it has anything to do with table flatness. When I converted to 510 SS had to send out 3 main tables before I found one that was acceptable. Even then it wasn't flat but I was embarrassed to ask for another table. Through the years I have regretted more than once not insisting on a flat table. Oh well live and learn today I would insist on a flat table or at least one that was flat enough I wouldn't get angry everytime I put a square on one side of the blade and then the other and see the difference.
Anyone know why the stop ribbing the whole table?
Ed
Main table ribbing
Moderators: HopefulSSer, admin
-
Ed in Tampa
- Platinum Member
- Posts: 5830
- Joined: Fri Jul 21, 2006 12:45 am
- Location: North Tampa Bay area Florida
I'll ask the Engineering staff for you, Ed, and post again tomorrow. But I want to address the problem of out-of-true table. More often than not, a table that appears not to be flat is actually improperly aligned.
When you loosen the four bolts to align the table to the saw blade, slip a $20 bill between the ribs on the rear of the table crossbar (part 514344) and the rear trunnion (514620). You can use a $1 bill, but you pay closer attention if you use a twenty. Align the table keeping the bill pinched in place, then tighten the two bolts you can reach without tilting the table. Remove the bill, tilt the table, and tighten the other two.
The bill serves as a feeler gauge and leaves a .005" gap between the trunnion and the crossbar when the bolts are tight. If the gap is too small, the table will bind when you try to tilt it. If the gap is too large, the tilt lock will pinch the two trunnions together when you tighten it and the table will warp.
Also check the mounting bolt holes in the trunnions. All four bolt holes should be the same size. If two holes are 3/8" dia and the other two are 1/2" dia, you may have a bad run that got past us many years back. When the table is tightened down, the improperly machined trunnions pull the table out of true. Send us the trunnions; we'll check them; and if necessary, replace them.
We carefully season the table castings until they are far from green, and we have excellent quality control on our surface grinding, still I won't deny that every now and then an out-of-true table squeezes through. But it's rare. Let's try these fixes first, then we'll take a look at your table.
With all good wishes,
When you loosen the four bolts to align the table to the saw blade, slip a $20 bill between the ribs on the rear of the table crossbar (part 514344) and the rear trunnion (514620). You can use a $1 bill, but you pay closer attention if you use a twenty. Align the table keeping the bill pinched in place, then tighten the two bolts you can reach without tilting the table. Remove the bill, tilt the table, and tighten the other two.
The bill serves as a feeler gauge and leaves a .005" gap between the trunnion and the crossbar when the bolts are tight. If the gap is too small, the table will bind when you try to tilt it. If the gap is too large, the tilt lock will pinch the two trunnions together when you tighten it and the table will warp.
Also check the mounting bolt holes in the trunnions. All four bolt holes should be the same size. If two holes are 3/8" dia and the other two are 1/2" dia, you may have a bad run that got past us many years back. When the table is tightened down, the improperly machined trunnions pull the table out of true. Send us the trunnions; we'll check them; and if necessary, replace them.
We carefully season the table castings until they are far from green, and we have excellent quality control on our surface grinding, still I won't deny that every now and then an out-of-true table squeezes through. But it's rare. Let's try these fixes first, then we'll take a look at your table.
With all good wishes,
Nick Engler
http://www.workshopcompanion.com
http://www.workshopcompanion.com
-
Ed in Tampa
- Platinum Member
- Posts: 5830
- Joined: Fri Jul 21, 2006 12:45 am
- Location: North Tampa Bay area Florida
Nick
Thanks for the suggestion.
I haven't done what you suggestted yet as I have a question.
If I remember correctly when I mounted my table I was told to use shims between the trunions and the table to warp it level.
I will look at my 510 upgrade instructions but if I recall correctly we used the sanding disk. Turned the table to vertical position and then moved the carriage so the table and sanding disk were close. Then we added shims until the table was parallel to the disk. I think I needed to put one or two shims between the trunion at one place to pull table level. Does that sound right?
I beleive the SS setup is much easier now, but I think you still sell the shims in the maintaince pak.
Ed
Thanks for the suggestion.
I haven't done what you suggestted yet as I have a question.
If I remember correctly when I mounted my table I was told to use shims between the trunions and the table to warp it level.
I will look at my 510 upgrade instructions but if I recall correctly we used the sanding disk. Turned the table to vertical position and then moved the carriage so the table and sanding disk were close. Then we added shims until the table was parallel to the disk. I think I needed to put one or two shims between the trunion at one place to pull table level. Does that sound right?
I beleive the SS setup is much easier now, but I think you still sell the shims in the maintaince pak.
Ed
The answers to your questions, Ed:
1. Just about the same time we introduced the 520, the mold for the table casting wore out. When we made the new mold, we decided to eliminate the ribs in the central section of the table because a fair number of user had complianed that these ribs made it difficult to make fine adjustments in the position of the stock before sawing. The "feathers" on the end of a freshly-cut piece would hang up on the edges of the ribs, preventing the woodworkers from sliding the board sideways.
2. It's absolutely impossible for the shims to warp or pull on the surface of the table. If you insert a shim between the trunnion and the table at any one of the four bolts, all that will happen is that the trunnion will pivot slightly to accommodate the shim and the table will tilt slightly front to back (or left to right, if you're working in the drill press mode). When the bolt is tightened the shim will impart no tension to the table surface and will make no difference in its flatness.
Before we go any further, let me define my terms and the adjustments you must make. I'm using "flat" and "flatness" to indicate the trueness of the table surface. The surface of a flat table defines a single plane; there are no low spots or high spots. This table has miter gauge slots and these slots should be perpendicular to the axis of rotation of the spindle in the sawing and sanding position. When the Shopsmith is in the vertical drilling mode, the table surface must be perpendicular to the axis of rotation from side to side (from one fence mount to the other) as you face the table.
Here's the procedure you should follow to align the table. This works for the 500, 510, and 520:
A. Check for flatness. If the machine is new, use a PRECISION GROUND straightedge to check that the table is flat. Don't trust a metal rule or a jointed board. Place the straightedge on the table so it stretches diagonally from corner to corner. You should not be able to slide a crisp new dollar bill folded in half (.010"-.012" thick) under the straightedge anywhere along its length. Check the other diagonal. If the table is not flat, there is nothing that you can do to true it short of taking it to a machine shop and having it reground. Send it back to us and we'll beat on it with a big hammer.
B. Square the table to the axis of rotation in the drilling position. Put the machine in the drill press postion and mount a sanding disc (without sandpaper) to the spindle. Adjust the table heigh so its 4 or 5 inches below the disc. There are several measuring tools you can use for what comes next, but the easiest by far is a dial indicator. (See http://www.shopsmith.com/ownersite/cata ... icator.htm.) Adust the indicator to measure the vertical distance between the table and the disc. Place the indicator tip against the disc near the edge and rotate the disc until you find the "high spot." (No sanding disc -- or saw blade, for that matter -- is completely true; they're all off by several thousandths.) Mark this high spot with a wax pencil or marker; you will make ALL of the following measurements from this spot ONLY.
Turn the disc so the high spot is to the left of the spindle and measure from the disc to the table at the spot. Turn the high spot to the right and repeat.
Shim the table on the left or right to make both measurements the same, adding shims between the table and the trunnions at the four bolt locations.) If you add one shim to one of the right-hand bolts, it will raise the table on the right HALF the thickness of the shim. If you add two shims, one to each of the right-hand bolts, it will raise the table on the right the FULL thickness of a single shim.
Incidentally, we've improved the machining quality of the trunnions so owners rarely have to resort to shims to make this adjustment on the 520.
C. Square the miter gauge slots to the axis of rotation in the sanding/sawing position. Set up the machine in the disc sanding postion and adjust the dial indicator to measure the distance between a table slot and the sanding disc. Loosen, but don't remove, all four bolts that hold the table to the trunnion. Put a $20 dollar bill between the crossbar ribs and the rear trunnion, as I mentioned earlier in this thread. Turn the disc so the high spot is close to the front of the table. Measure the distance between the disc and the table slot. Then turn the disc so the high spot is near the back and repeat. Position the table so both measurements are the same and the bill is still pinched in place. Tighten the bolts.
That's it for aligning the table, Ed. When you're finished the table should be under almost no tension whatsoever when the tilt lock is tightened. No warping; warping BAD.
We'll have a test on this on Monday, folks.
With all good wishes,
1. Just about the same time we introduced the 520, the mold for the table casting wore out. When we made the new mold, we decided to eliminate the ribs in the central section of the table because a fair number of user had complianed that these ribs made it difficult to make fine adjustments in the position of the stock before sawing. The "feathers" on the end of a freshly-cut piece would hang up on the edges of the ribs, preventing the woodworkers from sliding the board sideways.
2. It's absolutely impossible for the shims to warp or pull on the surface of the table. If you insert a shim between the trunnion and the table at any one of the four bolts, all that will happen is that the trunnion will pivot slightly to accommodate the shim and the table will tilt slightly front to back (or left to right, if you're working in the drill press mode). When the bolt is tightened the shim will impart no tension to the table surface and will make no difference in its flatness.
Before we go any further, let me define my terms and the adjustments you must make. I'm using "flat" and "flatness" to indicate the trueness of the table surface. The surface of a flat table defines a single plane; there are no low spots or high spots. This table has miter gauge slots and these slots should be perpendicular to the axis of rotation of the spindle in the sawing and sanding position. When the Shopsmith is in the vertical drilling mode, the table surface must be perpendicular to the axis of rotation from side to side (from one fence mount to the other) as you face the table.
Here's the procedure you should follow to align the table. This works for the 500, 510, and 520:
A. Check for flatness. If the machine is new, use a PRECISION GROUND straightedge to check that the table is flat. Don't trust a metal rule or a jointed board. Place the straightedge on the table so it stretches diagonally from corner to corner. You should not be able to slide a crisp new dollar bill folded in half (.010"-.012" thick) under the straightedge anywhere along its length. Check the other diagonal. If the table is not flat, there is nothing that you can do to true it short of taking it to a machine shop and having it reground. Send it back to us and we'll beat on it with a big hammer.
B. Square the table to the axis of rotation in the drilling position. Put the machine in the drill press postion and mount a sanding disc (without sandpaper) to the spindle. Adjust the table heigh so its 4 or 5 inches below the disc. There are several measuring tools you can use for what comes next, but the easiest by far is a dial indicator. (See http://www.shopsmith.com/ownersite/cata ... icator.htm.) Adust the indicator to measure the vertical distance between the table and the disc. Place the indicator tip against the disc near the edge and rotate the disc until you find the "high spot." (No sanding disc -- or saw blade, for that matter -- is completely true; they're all off by several thousandths.) Mark this high spot with a wax pencil or marker; you will make ALL of the following measurements from this spot ONLY.
Turn the disc so the high spot is to the left of the spindle and measure from the disc to the table at the spot. Turn the high spot to the right and repeat.
Shim the table on the left or right to make both measurements the same, adding shims between the table and the trunnions at the four bolt locations.) If you add one shim to one of the right-hand bolts, it will raise the table on the right HALF the thickness of the shim. If you add two shims, one to each of the right-hand bolts, it will raise the table on the right the FULL thickness of a single shim.
Incidentally, we've improved the machining quality of the trunnions so owners rarely have to resort to shims to make this adjustment on the 520.
C. Square the miter gauge slots to the axis of rotation in the sanding/sawing position. Set up the machine in the disc sanding postion and adjust the dial indicator to measure the distance between a table slot and the sanding disc. Loosen, but don't remove, all four bolts that hold the table to the trunnion. Put a $20 dollar bill between the crossbar ribs and the rear trunnion, as I mentioned earlier in this thread. Turn the disc so the high spot is close to the front of the table. Measure the distance between the disc and the table slot. Then turn the disc so the high spot is near the back and repeat. Position the table so both measurements are the same and the bill is still pinched in place. Tighten the bolts.
That's it for aligning the table, Ed. When you're finished the table should be under almost no tension whatsoever when the tilt lock is tightened. No warping; warping BAD.
We'll have a test on this on Monday, folks.
With all good wishes,
Nick Engler
http://www.workshopcompanion.com
http://www.workshopcompanion.com
Nick,
My table was sticking really badly whenever I tilted it for drill press mode, so I tried your trick using a dollar bill since I didn't have any 20's. I'm pretty sure I put the bill in the right place, but the table is still hard to tilt to 90 degrees. In fact, it's so hard that when I do, it emits a loud "screech" like fingernails on a chalk board. Any other ideas?
Bruce
My table was sticking really badly whenever I tilted it for drill press mode, so I tried your trick using a dollar bill since I didn't have any 20's. I'm pretty sure I put the bill in the right place, but the table is still hard to tilt to 90 degrees. In fact, it's so hard that when I do, it emits a loud "screech" like fingernails on a chalk board. Any other ideas?
Bruce
Bruce, if the table sticks at only one position, the ribs on the crossbar are rubbing on the inside surfaces of the trunnions. One of two things is wrong. (1) These surfaces are gauled or, more likely, (2) one or both of the trunnions are toed in.
If the surfaces are gauled, the solution is to lap the trunnions the same way you lap a hand plane to flatten the bottom.
If the trunnions are toed in, this has worked for me: True the table the way I described in "C" earlier in this thread, then remove it from the carriage. Turn it upside down on your workbench. Loosen the tilt lock and tilt the posts so they are in the drill press position. Do NOT tighten the tilt lock. Loosen the to table mounting bolts closest to the legs. Leave the other two tight -- they will hold the table in the alignment you just worked so hard to make, but the toed-in trunnions will spirng out right and left ever so lightly. Snug up the mounting bolts and test the tilting action -- it should be much better. If you're satisfied, tighten the two mounting bolts completely.
Tilt the legs all the way in the opposite direction until the 45-degree stop contacts the table. If the table does not tilt smoothly in this direction, the trunnions are toed-in on this side of the table as well. Loosen the two table mounting bolts closest to the legs and go through the same procedure as descibed in the previous paragraph.
You shouldn't loose your table alignment doing this as you only loosen two bolts at a time -- the other two remain tight and hold the alignment while you're correcting for the toe-in.
With all good wishes,
If the surfaces are gauled, the solution is to lap the trunnions the same way you lap a hand plane to flatten the bottom.
If the trunnions are toed in, this has worked for me: True the table the way I described in "C" earlier in this thread, then remove it from the carriage. Turn it upside down on your workbench. Loosen the tilt lock and tilt the posts so they are in the drill press position. Do NOT tighten the tilt lock. Loosen the to table mounting bolts closest to the legs. Leave the other two tight -- they will hold the table in the alignment you just worked so hard to make, but the toed-in trunnions will spirng out right and left ever so lightly. Snug up the mounting bolts and test the tilting action -- it should be much better. If you're satisfied, tighten the two mounting bolts completely.
Tilt the legs all the way in the opposite direction until the 45-degree stop contacts the table. If the table does not tilt smoothly in this direction, the trunnions are toed-in on this side of the table as well. Loosen the two table mounting bolts closest to the legs and go through the same procedure as descibed in the previous paragraph.
You shouldn't loose your table alignment doing this as you only loosen two bolts at a time -- the other two remain tight and hold the alignment while you're correcting for the toe-in.
With all good wishes,
Nick Engler
http://www.workshopcompanion.com
http://www.workshopcompanion.com
-
Ed in Tampa
- Platinum Member
- Posts: 5830
- Joined: Fri Jul 21, 2006 12:45 am
- Location: North Tampa Bay area Florida
Nick
I have a question. When do step C you say adjust the table until both measurements are the same. I was using a dail indicator and I messed and I played and I messed and I played and to the best I could get the two was two points on the scale difference front to back.
The scale I used has .1 - .9 with one revolution being .10 of inch. So I think the numbers are .01 of an inch with the little marks in between being .001 of an inch. If I'm reading it right that means I have the table adjusted to .002 between the front measurement and the rear.
While they are not the same I think that is probably closed enough since both measurements will change if I just slap the table with my hand.
What say you am I close enough or should I continue until I get zero if that is possible?
I have a question. When do step C you say adjust the table until both measurements are the same. I was using a dail indicator and I messed and I played and I messed and I played and to the best I could get the two was two points on the scale difference front to back.
The scale I used has .1 - .9 with one revolution being .10 of inch. So I think the numbers are .01 of an inch with the little marks in between being .001 of an inch. If I'm reading it right that means I have the table adjusted to .002 between the front measurement and the rear.
While they are not the same I think that is probably closed enough since both measurements will change if I just slap the table with my hand.
What say you am I close enough or should I continue until I get zero if that is possible?
-
dusty
- Platinum Member
- Posts: 21371
- Joined: Wed Nov 22, 2006 6:52 am
- Location: Tucson (Wildcat Country), Arizona
Main Table Ribbing
I have to quit reading these posts. Each one causes me to find something else that seems to need attention. I have Christmas presents to build and there isn't enough time to be fooling around on this computer...at least that is what I have been told by "the supreme authority in this household".
Assuming that gauling is 'unwanted scratches, gouges, etc' my trunnions are badly gauled. The table tilts as freely as I believe it ever has but there certainly is some drag. I've waxed the inboard sides of the trunnions but I don't think it helped anything...and (before someone tells so) I know that the manual does NOT recommend waxing.
After Christmas, I'll try to borrow a $20 and try a documented solution.
Incidently, I cleaned the wax off the trunnions for now.
Assuming that gauling is 'unwanted scratches, gouges, etc' my trunnions are badly gauled. The table tilts as freely as I believe it ever has but there certainly is some drag. I've waxed the inboard sides of the trunnions but I don't think it helped anything...and (before someone tells so) I know that the manual does NOT recommend waxing.
After Christmas, I'll try to borrow a $20 and try a documented solution.
Incidently, I cleaned the wax off the trunnions for now.
The manual doesn't recommend waxing the inside surfaces of the trunnions, Dusty, but I do. The only reason the manual says not to is because we occasionally get new owners who apparently never learned to color within the lines and smear wax all over trunnions and anything else within spitting distance.
And Ed, if you've got that table trued to the axis of rotation within .002", then you're about .003" ahead of where I usually give up. I should have written, "...position the table until both measurements are as close as you can make them (within .005" or better)."
"Gauled" is where the metal is gouged and a slivver or a ribbon of metal -- called a gaul -- rolls up, creating both a low spot (the gouge) and a high spot (the gaul). The gaul wedges between the surfaces of the ribs and the trunnions as they swing past each other and cause them to bind. This is very unusual -- you really have to abuse the machine big time to create the gauls. As for having scratches on the trunnions -- well, who doesn't?
With all good wishes,
And Ed, if you've got that table trued to the axis of rotation within .002", then you're about .003" ahead of where I usually give up. I should have written, "...position the table until both measurements are as close as you can make them (within .005" or better)."
"Gauled" is where the metal is gouged and a slivver or a ribbon of metal -- called a gaul -- rolls up, creating both a low spot (the gouge) and a high spot (the gaul). The gaul wedges between the surfaces of the ribs and the trunnions as they swing past each other and cause them to bind. This is very unusual -- you really have to abuse the machine big time to create the gauls. As for having scratches on the trunnions -- well, who doesn't?
With all good wishes,
Nick Engler
http://www.workshopcompanion.com
http://www.workshopcompanion.com