Building a drum sander, question on conveyor

[Mike Reinholtz]

Good morning!
I have started building a drum sander and have some questions I hope someone can help me with. I designed the frame from square tube steel and have most of it welded together, I'm mounting the pillow blocks and 6" drums this weekend and getting close to putting together the conveyor. I have looked online quite a bit and have a few different sources for the belt, but I'm torn on what to use. I read in a few places that some manufactures actually use sand paper belts for the conveyor because it grips so well, others use a rubber belt. Anyone have any experience with the machines that used sandpaper belts? I found they are cheaper and available in more sizes that would work for me, but I don't want to go that route if it won't perform as well. I'm not trying to do this on a super cheap budget but I don't want to break the bank either. The design is closed on both sides, has 25" drums, a 5hp motor for the drums, and a 1/2hp DC motor for the drive. The feed rate is infinitely variable up to about 18fpm.

When I started designing this machine I had only planned on using a single drum, but that changed and currently I am building a dual drum machine. I was thumbing through the Grizzly catalog last night and found a planer/sander combo ($13K- ouch), and that got me thinking- maybe a spiral cutterhead should go in that first slot... probably need a bigger motor for that. Maybe a 7.5HP with a woodmaster 25" spiral head...

I don't think I've ever built something as planned, always gotta "improve" it as I go. ugh.

Mike

[Britt Kelch]

good luck sounds like a good project my advice is to either use a rubber compound that cant transfer materia to the wood. I have a woodmaster 718 4 in one machine and it feeds at up to 24fpm and I personally have never needed that kind of speed it has some kind of rubber rollers and a 1/6hp drive which I have tried to bogg down no luck. I have also owned a sand paper conveyor so far no problems either way sorry but its a draw.I think the paper should be cheapeast way to go and with a 1/2hp motor it should pull a tree through. Good luck and postsme pictures of your progress on smc.:)

[Greg Sznajdruk]

www.sawmillcreek.org/showthread.php?t=87536&page=2 (http://www.sawmillcreek.org/showthread.php?t=87536&page=2)

This may be of benifit Merza has a number of threads on Home Made drum Sander.

Greg

[Mike Reinholtz]

Thanks Britt for the info on the belts, good to know either way I go they should do the job. Right now I'm thinking I will try the sanding belts, most of the machines I looked up online that use these come with 120 grit. Next step is if I should use open or closed grit. I have plans for a brush line to gently touch the drums as they exit the top housing to aid in dust collection and to use the brushes at the inlet and outlet of the conveyors, this should help considerably with the dust collection. Speaking of which, I plant to start with 6" and see how my DC does, maybe switch to 4" if the fpm isn't enough. I'm running a 2hp Grizzly and plant to add a Wynn canister, hopefully it's enough airflow.

The final drive ratio for the conveyor hasn't been set yet and while I was thinking of going with a slower drive system I don't think I will need to worry too much about torque. If I end up modifying this to use a spiral planer head and a drum I may look into using driven pressure rollers on top to aid in pulling material through, this might also help reduce (or eliminate) slipe.

Greg- I checked out that link when I was drawing up more of the plans for this machine, lots of great info in there. It's great to hear he still uses it after 2 years and to hear that he was able to make it so accurate.

Right now the frame is pretty ugly, just welded tube steel with primer and holes drilled for the pillow blocks. Once it looks like I'm making progress I will post some pics.

Any input or ideas of how you would change something you have seen please let me know, I really appreciate it!


Mike

[mreza Salav]

Mike,

I have more pictures of the progress here:
http://good-times.webshots.com/album/563359635TjeHYY?start=0

As you see I used a sand paper belt for conveyor. I looked into getting a rubber version but they were very pricy (like $300). It has worked fine; except in a few occasions when I was sanind very thing (like 1/16" or less) material it tended to slip over the belt.

One thing that I would change if I was going to build it again would be to use something very flat for the table that would stay truely flat, like granite.
I have to check mine more carefully but at that width (29") it can go out of flat a bit, especially if you mostly put your pieces in the middle.
My table right now is a 3/4" laminated MDF on top of a 1.25" thick platform built out of maple. The 2" thick table seems very stable but I am thinking of replacing the MDF with a slab of granite. I have checked around and I can get it for about $50 or so.

The good thing about builing it yourself is, if you don't like something about it, most likely you can change/fix it :D
I still love mine and I am very glad I made it.

[Mike Reinholtz]

Mreza- Thanks for the tips, I went on craigslist and found a couple guys selling scraps of Granite. The slab I emailed for is 36" x 30". I really appreciate the help, nice to hear of the upgrades you are considering. The sanding belt I picked for the conveyor is 37"x 75", might have to trim it a little.