Main table difficult to raise and lower

[dusty]

20200430_054108.jpg (1.5 MiB) Viewed 6553 times

When positioned as shown here, there should be NO rocking motion when you apply pressure at different points on the legs (meaning the legs are in the same plane).

How about one leg at a time inserted into the carriage?

[donpol]

Update:

In an earlier post I said how I had found that the table posts were bent slightly and they weren't at 90 degrees to the tie bar or the table. I believe this misalignment caused the friction when raising and lowering the table.

Today, I attempted to straighten the posts. I clamped the table to a workbench and using a pipe for leverage, applied some force to one of the posts. Almost instantly the tie bar snapped in two. Upon closer inspection I found that I also snapped part of the front trunnion.

Just for curiosity sake, I installed each post in the carriage where they would normally go and they each travelled through a full range with no friction. I believe this supports my initial theory that the misaligned posts were the problem.

[dusty]

Update:

In an earlier post I said how I had found that the table posts were bent slightly and they weren't at 90 degrees to the tie bar or the table. I believe this misalignment caused the friction when raising and lowering the table.

Today, I attempted to straighten the posts. I clamped the table to a workbench and using a pipe for leverage, applied some force to one of the posts. Almost instantly the tie bar snapped in two. Upon closer inspection I found that I also snapped part of the front trunnion.

Just for curiosity sake, I installed each post in the carriage where they would normally go and they each travelled through a full range with no friction. I believe this supports my initial theory that the misaligned posts were the problem.

It certainly does appear to be proof of theory. I was a doubter but now I believe.

Don't discard your table posts. You will be amazed at how often they come in handy.

[JPG]

Good Grief!

Now we will never know the cause of the problem.

Nowhere did I see any attempt to determine if the tubes were 'parallel'.

[donpol]

Good Grief!

Now we will never know the cause of the problem.

Nowhere did I see any attempt to determine if the tubes were 'parallel'.

This MKV was a recent purchase. The seller inherited it from a family member. I believe that some incident caused the main table posts to be bent.
Possible scenarios:
Someone bumped into it with a car in a garage.
It was transported lying flat on it's "back" with the main table installed and the weight of the machine bouncing down the road bent the posts out of alignment.
Someone was carelessly rolling it around and knocked it onto its back.

This unit is from the 70's, so it's anyone's guess what's happened to it.

As for the check for parallel, I didn't post that, but before I tried bending the post I did check. Laying the posts on the table (as was suggested) showed the posts to be parallel; they were flat on the table their entire length. I also measured the distance between the posts and they were parallel. They were however, out of square to the table, which I believe caused the difficulty moving the table up and down.

[JPG]

Yes that would create an off set in the positioning of the rack teeth(vertical).

So it appears we now DO know the source of the problem if not the cause!

Thank you for following through on this. We hate non-understood problems.