Z-Table: threaded posts are not straight

[trichard3000]

I recently purchased and received the "Power table/ bed kit for K40 small laser machine." Upon assembly, I found that two of the threaded posts (with the brass gears at the bottom) are not straight enough for the table to work properly. The two faulty posts vary by enough that once the table surface is tightened to the brass carriers, the differences caused by the curved posts are enough to cause the bed to bind up and not raise or lower.

I am tempted to try to straighten these myself but I fear that this will only make things worse. One of them has a noticeable curve that varies from the center line by roughly a mm or two over the length of the post, the other is deformed in more of a "corkscrew" pattern.

How can I go about getting a replacement set of known-straight, threaded posts?

I hate to air this in a public forum, as all in all the quality of this kit seems high but this looks to be my only path for tech support.
Thanks in advance for your help.

[NickWL]

I had this exact same problem Though the kit I bought was a 'second' having been returned by a previous buyer.
Two things: I tried straightening the threaded rod but in the end went to a hardware shop, bought a 1 metre length for about £3 and took it down to a friendly clockmaker who turned out two new drive rods for me in exchange for a bit of help with the emailing of his photos (I'm a PC maintenance man by day).
Every time I tightened the z-table up fully it would lock; I discovered that the key is to (you guessed it!) NOT tighten the top four screws fully up. In fact I put a washer atop all for support posts and then just hand-tightened.
That was several months ago and it has worked like a dream ever since – in spite of being and out of the machine when replaced with a rotary bed.
Nick

[trichard3000]

So I couldn't wait and tried to straighten out the threaded posts a bit. I played around with loosening up the frame in places and even tried to align the crooked posts with each other, to try to align the forces on the bed in the same directions.

In the end, I managed to reduce the binding and the bed now goes up and down freely. However, the it "orbits" slightly around the Z axis as the bed goes up and down. In other words, X and Y values vary by 1-2mm as Z changes. This works okay for it's main purpose with my laser cutter, although I had some other use cases I was pondering that would require accuracy along X and Y.

Is there an option to buy replacement posts directly from Lightobject or should I look in to making a set locally as NickWL did?

If I go local, any advice on getting the gear off the end of the current post?

Thanks!

[Tech_Marco]

What is your order number? I'll send you two replacement.

Marco

[trichard3000]

Marco, thanks for your good customer service, even after I let you off the hook!

This is the best way to earn future business. It seems that upgrades to these cutters are a slippery slope. I feel that the full DSP conversion is in my future. Also, once I get my cutter dialed in, I'm thinking about building a sous vide cooker and you offer many of the parts I need.

My order number is 203977. Thanks again for resolving this.

[trichard3000]

I received my threaded posts over the weekend. Thanks for your prompt customer service!

[overkill71]

Not meaning to hi-jack your post but figured here is a good place to post mine.

Marco, I have the same problem. I got my table today, assembled it and all wired up very easy. Table just grunts. Took apart and have two bent threaded rods and a third rod has the belt retaining ring off of it.

Any chance to get a new set as well. My order was shipped to Olive Branch MS. Order number 119156B

Thanks

[Tech_Marco]

Do you have the original order number instead?

Marco

[overkill71]

Got my z table working. I had to put a .030" washer on top of each of the 4 post on the top rails of the fixture. The problem is that the 4 threaded rods were all different lengths. Once I installed the washer shims, the table now has full travel up and down. I even installed a Z axis lower limit switch so it now homes out.

Maybe this will help someone else.


Thanks,

Russell