Performax 16-32 defective platen?

[Charlie Kocourek]

I bought an older Performax 16-32 a while ago. It did not work very well and I did not really use it much. Finally, I decided to tune it up and get it working. After much adjustment I got it working but still not good enough.

I ran a 12X20" piece of finished 1/2" plywood through it and it only sands the center 7-10 inches or so.

Then I checked the flatness of the conveyer platen. It is perfectly straight and flat on the outside edge, but it progressively dips as it goes accross to the inside edge. The inside edge of the platen has a long shallow dip to the center right under the drum. This dip is about 1/8" or more lower than conveyer rollers.

I do not see why this would cause the problem that I am seeing, but nor can I see how it could possibly produce a flat board against a surface that is not.

It seems to me that this is probably a defect.

So, I am wondering if you guys (and gals) who own these machines have flat platens or is this typical of these things?

Thanks, Charlie

[Doug Shepard]

Are you checking flatness with the feed belt on or off? I do know the belt can get waviness in it over time from humidity changes. I basically just work around this by keeping downward pressure on the work as well as on the back end while feeding it through. Yeah, it's tedious but it works, and I dont know how long a replacement feed belt would last before getting the same problem.

[James Suzda]

<snip> Then I checked the flatness of the conveyor platen. It is perfectly straight and flat on the outside edge, but it progressively dips as it goes accross to the inside edge. The inside edge of the platen has a long shallow dip to the center right under the drum. This dip is about 1/8" or more lower than conveyor rollers.

I do not see why this would cause the problem that I am seeing, but nor can I see how it could possibly produce a flat board against a surface that is not.

It seems to me that this is probably a defect.

So, I am wondering if you guys (and gals) who own these machines have flat platens or is this typical of these things?

Thanks, Charlie
Charlie,
I just went down to the shop and checked my 16/32 and as far as I can see with my limited straight edges it is perfectly flat from edge to edge and from roller to roller. (I didn't take the conveyor belt off for obvious reasons.):p
I'm assuming that you bought this unit used and I just wonder if the previous owner screwed the head down tight enough to bend the platen. Stupid question, but you do have your drum head perfectly aligned with the conveyor even if it does dip?
Good luck!

[Charlie Kocourek]

Thanks for the replies.

I am checking it without the conveyer belt. The metal itself is not straight.

Also, I am not sure if aligning the drum to the crooked platen would work because it would be impossible to align the outfeed tables since they sit higher than the platen, at least on the inside.

At this point I am concidering two options. Either spread a coat of bondo over the whole platen and "fill in the dip", or double face tape to a thin piece of soft wood to the platen and then hand plane it down until it is flat. Neither of these sound all that easy. But, I am leaning towards the thin piece of wood because if the bondo set up too fast then it could be a real mess over an area that large.

Any other thoughts?

[James Suzda]

Thanks for the replies.

I am checking it without the conveyer belt. The metal itself is not straight.


Any other thoughts?
Why don't you check with Performax to see what a new bed would cost, or take it to your "local machine shop" to see if they can make you one.

[Mike Cutler]

I ran a 12X20" piece of finished 1/2" plywood through it and it only sands the center 7-10 inches or so.

I think I would be putting a straight edge on the drum to see if it has a crown in the center.
If there is a dip in the center of the platten, it would seem that the effect would be the opposite of sanding only the middle.

[John Lucas]

There is another thing you can try...may not be a permanent fix but may reveal or suport your findings. Get a piece on 3/4 MDF or white melamine pc board that is flat and put the piece you want to sand on top of it and feed both together. You should get flat. Also, take off very little on each pass. Where bed is flat or not, I find the 16/32 doesnt take off heavy amounts quickly...it often will either stop/strain, burn the belt or tear it. It is not uncomomon for me to advance the crank 1/6 a turn per time. It takes for ever but it isnt meant as a thicknesser...just a sander. And keep the blet clean with a rubber crepe.

[Charlie Kocourek]

:D I took John's advise, sort of, and it worked! I filled in the dip in the platen with a few layers of veneer and got it pretty close to flat. Then I looked closer at the adjustments and tweeked them some more and viola! It works great.

I have heard so many people say that they love these machines and nearly as many say they can't stand em. Now I know see sides of this and while I don't love it (yet) I can see why some people would.

Thanks to all who replied.

Charlie