changing conveyor belt on supermax drum sander

[mreza Salav]

I have a supermax 37x2 drum sander. It is one of those tools that I hate but need it. Hasn't been a great machine at all...

last issue was the edge sof the conveyor belt have buckled up a bit (stretched?) and eventually caught up with the drum and completely tore apart while sanding a veneer.
Instead of buying another sand-paper belt I am thinking of having a heavy duty rubber belt ordered for it. I found a couple of suppliers of industrial conveyor and they can custom make one for me but the price is around $400-450(CAD$) which is a bit steep.
Has anyone done this before and do you think it's a worthwhile expense?

[David Kumm]

What does Supermax charge for their waffle belt? The only downside with the waffle type is the regular sanding belt gives you a more consistent thickness on thin veneer. I found that as soon as a belt developed a tear I had to cut a piece off or the tear would catch the drum and soon nothing was left. Kept a utility knife to hack out a semi circle around the tear so there was no point for it to continue. Dave

[mreza Salav]

Thanks Dave for suggesting contacting them. They have a rubber one and they sell for $300. Their tech dept. did say it doesn't hold wood as good as the abrasive belt. So I am now wondering which one should I get. I don't like paying more for a product that has other issues...
I can get a 3rd party abrasive belt (from supergrit) for $45.

[Sam Layton]

Hi merza,

I have the same sander as you with the original belt. I have often though about replacing it with the rubber waffle belt. However, I had concerns that David mentioned. Mine is getting close to needing replacing. I can't get over the $300 price tag on the waffle belt. I have been thinking that when it is time, I will go with the abrasive belt.

Do you have problems getting yours to track properly? I am always having to fiddle with mine to keep in tracking properly...

Let us know what you decided, Sam

[mreza Salav]

Sam, I have to constantly fiddle with the screws to keep the belt tracking properly; over a long job they tend to move left or right no matter how small an adjustment I make.
I had issues with the elevating screws: the two gears on one end (where the handle is) would slip due to the set screw not holding tight the gear on the shaft. Eventually the set screw completely stripped the soft metal of the gear. I think it is a very bad design to expect that soft metal with a setscrew hold the gear tight to transfer power to the other elevating screw as there is no key (just a flat spot on the shaft with setscrew over it). I bore a larger hole all the way through the shaft and tapped the gear and put a bolt through the gear and the shaft. That problem is now solved (at least on one side). I have problem with holding the sand paper on the drums, I pull them tight and after a run or two retighten but sometimes they come loose so slightly that overlap and burn. I end up applying a bit of spray adhesive to the back of the belt (which creates a mess and has to be cleaned each time I change sand papers). And now the belt needs to be replaced...

Do you know what is the type of their rubber on their conveyor? when you say waffle, is it a thick rubber with a waffle type texture (typically gray color) that is seen on some belt sanders or is it a thin black poly belt? They called it poly when I spolke over the phone and looking at the pictures of their brush sanders it seems it is the latter, which I'm not interested in...

[David Kumm]

Tracking does seem to be a problem but I'm not sure the belt itself isn't the problem. Belts are made for WB sanders with oscillation and more complicated tracking methods so any manufacturing error in circumference doesn't matter like it does on the conveyor application. A new belt might make the problem better- or worse. I did find that there gearing and conveyor need to be adjusted just right or they slightly bind as the table is raised and lowered which ultimately screws up the gears. The table should operate very freely when moved or it is binding. The clips on the drums are finicky but mine seldom loosen after attached. You do need to be careful the belt end isn't too lond when inside the drum or the spring clip won't seat quite right and pull the belt tight. They can also get a little bent and not pull tight as well. Fussy machine that needs a few hours of adjustment but then stays pretty good. Dave

[mreza Salav]

Thank Dave. My table doesn't move "very freely" for sure. It is hard to turn the handle with one hand. I guess it could be that the table is slightly bind but is parallel to the drums (so I need to first find a proper adjustment on the table that moves freely and then adjust the drums to the table).
I wish I could see their non-abrasive belt...

[Sam Layton]

Hi merza,

I think David hit the nail on the head. I think it depends on how close the tolerances are when they make the belt. I have heard of other people with other sanders purchasing new belts and it has helped a lot. I don't have any problems with the sand paper coming loose. Raising the table up and down is a bit hard. I just keep it adjusted and lubed and it works OK.

I do not know what type of rubber it is. Just looking at different make sanders with the rubber belt, it looks like a waffle design. My good friend, Rick Potter has a Wood Master drum sander, and I think it has the rubber belt. Maybe he will comment, or you could pm him.

Sam

[mreza Salav]

Thanks Sam. I will most likely buy an abrasive belt. I am in the middle of building a house and aside from the house expenses have spent over $11k on tools in the lately so will wait for another time to get a better belt.

I just looked at the manual and to have the drums adjusted to the table it suggests to disengage the gears (on one side) and move the table up or down on that side. So how do you make the table move easily/freely and have the drums parallel to it afterwards? I have my drums parallel but at times rotating the handle to raise the table by one hand is pretty hard.
Dave, do you have this machine? how do you go about getting this adjustments?

[David Kumm]

I had both a 25x2 and 37x2 but it has been a few years as I upgraded to a WB. I remember one table moving hard and I loosened everything and got the gearing working easily. I think I may have gotten close with the gears meshing and then shimming the table. A carton of machine shims is standard equipment in my world. I do remember it was a trial and error- mostly error method. Dave

[mreza Salav]

Thanks Dave. It's a fiddly machine for sure.

[David Kumm]

It did a lot of work for me though. Great for veneers and glue ups. Learned to use polyurethane glue to save the belts. Don't like the stuff much but much easier on the belts. Never had much luck with grits finer than 120. Did 80 and 120 most of the time. Good luck. Dave

[Sam Layton]

mreza, I don't like the design of our sanders. However, as I remember when I got mine, it was the only game in town... Mine is on wheels, but I don't move it around. It seems to me that if your shop floor is uneven it could tweak the sander if you roll it around. So I just leave it in one place.

Cranking the table on mine is not easy, but it is not as hard as yours seems. I did adjust the drums to the table. The sleeves that ride on the vertical poll have adjusting screws that takes out the play between the sleeve and poll. Make sure you have no play, but make sure they move freely. I use dry lube on the poll. Make sure all of your bushing are lubed as well.

I disengaged the gear on the non handle side, and cranked the other side which ever direction was necessary to make the drums and table parallel. Then I got two pieces of 4/4 wood about 2" wide, and 18" long. I ran them on each end of the drum and table, and then measured them. I kept adjusting the sprocket until both pieces of wood measured the same.

It may be a good idea to clean your poll with lacquer thinner, and maybe sand them a little with 600 grit sand paper to make sure the polls are smooth. Then lube with a dry lube.

Sam

[Bradley Gray]

I have a 25 x 2 and when I first bought it the drive belt was damaged. I ordered a new belt from one of the woodworking catalogs and had lots of tracking problems. I called supermax and was told that one of their belts would track better. I did this and the sander performs much better but still requires occasional tweaking. If I'm doing a lot of sanding I keep a wrench in my back pocket and adjust on the fly.