Main table difficult to raise and lower

[donpol]

I have recently acquired a 1970's era Mark V with the 500 tables. I'm having difficulty raising and lowering the main table. What happens is this: If I start with the main table completely out of the casting that holds it to the way tubes, I have difficulty installing it. When I go to put the support tubes into the casting they don't seem to line up with the gears in the casting. The table will go in with some difficulty and then it will be difficult to raise and lower the table using the handle. This happens about 9 out of 10 times. Occasionally when I put the table in, the gears will mesh and the table will move up and down very easily. Because of this I'm thinking there may be some alignment issue with the table posts or the gears in the casting.

I've tried cleaning everything. I took out the gears and the square rod that holds them in place and everything seems to be in alignment. I've even tried oiling the gears just to see if that would help. Nothing seems to help... I've owned several 500s over the years and never had a table this difficult. I don't currently own another 500, so I can't try switching the table from one unit to another.

I'm wondering if the posts on the table could be out of alignment somehow and if there is a way to check? Or, if there is something else I should be looking at.

[garys]

Your best bet is probably to do a serious visual inspection and some measurements. Likely you will find something that is out of alignment or damaged.

[br549]

There was recently another post (https://www.shopsmith.com/ss_forum/main ... 23532.html) about table posts that came with a double tilt upgrade (teeth on two sides of the posts), and the teeth were apparently not machined parallel to the pins that hold the posts in the castings.

Being so old, it is doubtful that your are mis-machined, but you might check that the posts are securely attached ... if the pins are missing, maybe your posts have just been twisted slightly. Or possibly they have been slightly bent.

[davebodner]

I find re-installing the table is easier if I loosen the clamp way more than I think should be necessary. My table raising mechanism works just fine, otherwise.

[dusty]

When I install the table assembly into the carriage the table normally slides right in and runs down without my touching the table height adjust. However, I occasionally set the table legs into the carriage and it does not slide right in. When that happens turning the crank seems to engage the gear teeth and then adjustment is normal.

You said yours adjusts easily, SOMETIMES. I read that to mean that there is nothing wrong with the table support legs or the carriage. Clean and wax the support legs and make sure the gears are free of sawdust and gunk that could interfere. Hope you get this resolved without series issue.

[JPG]

When I insert the table legs into the carriage bores one of two things happens.

1) It slips into the gears and must be restrained from falling till the table hits the carriage. HOME FREE!!

2) It wants to hang up on the gears. Then I rotate the elevator crank(as if raising) to allow the gears to mesh correctly. Once they align we are back to "1".

When the 'tooth' part of the tubes hits the 'tooth' part of the pinion gear(s), nothing will allow the table to lower.

I am puzzled by your third condition. Lowers with stiffness??? Is it possible only one tube is correctly meshed and the other is somehow skewed?

[donpol]

Upon closer inspection, I believe I have found the problem...

I removed the table and inspected everything for dirt, rust, burrs, damage; nothing unusual. Not finding obvious damage, I suspected something may be bent. With the table upside down on my bench I measured the table support posts to see if they were parallel to each other and they were. Using a square against the trunion casting I found that both posts were not exactly 90 degrees to the table. My guess is that the previous owner may have transported the Mark V on it's side with the table installed, and the weight of the machine was supported by the table, which would explain the table's support tubes being off from 90 degrees.

I believe that having the table posts slightly "bent" from 90 degrees to the table would cause difficulty lining up the gear teeth and some friction also.

I don't think I will be able to bend them back to exactly 90 degrees. So I may replace the parts or just live with it.

[dusty]

Upon closer inspection, I believe I have found the problem...

I removed the table and inspected everything for dirt, rust, burrs, damage; nothing unusual. Not finding obvious damage, I suspected something may be bent. With the table upside down on my bench I measured the table support posts to see if they were parallel to each other and they were. Using a square against the trunion casting I found that both posts were not exactly 90 degrees to the table. My guess is that the previous owner may have transported the Mark V on it's side with the table installed, and the weight of the machine was supported by the table, which would explain the table's support tubes being off from 90 degrees.

I believe that having the table posts slightly "bent" from 90 degrees to the table would cause difficulty lining up the gear teeth and some friction also.

I don't think I will be able to bend them back to exactly 90 degrees. So I may replace the parts or just live with it.

Help me to envision this, please. Post a picture of this process. Because I occasionally have the same experience though seldom, I doubt your conclusion. Also, you said that sometimes it works well????

[donpol]

Dusty,
here are pictures of how I checked. The part I was referrring to as the trunnion is actually the tie bar (part #151). You''ll notice in the close up photo that the square is not touching the post, meaning that the post is not at 90 degrees to the tie bar.

[dusty]

Thank you. Excellent image. The table support shown is clearly not square to the tie bar but...is the tie bar the correct reference system. If the two legs (table supports) are parallel, they should move up/down in the carriage smoothly.

With a framing square snug against the ends of the two support legs does it also properly contact the the vertical surface of each leg.

Disclaimer: My experience involves only Mark V tables but it appears that the tie bars are the same (comparable).