Slack Belt Sander

[brurobas]

Good afternoon guys,

I hope everybody is doing fine.

I came across some pieces of an old belt sander from a closed business and the price was so nice i bought them even though i didn't knew if i could use them.

I have been wanting to build some kind of large vertical belt sander but since i don't know how to weld or build frames, or pulleys, etc, i never got to do it.

If any of you could help me understand if i can use these to build some kind of belt sander it would be great and i would really appreciate it.

I am going to use the motor from a wood lathe with 760 rpm.

As for the wheels, the Idler Wheel has a diameter 5'' and is 3.15'' wide. The Rubber Wheel has a diameter of 8'' and is 2'' wide.




Will this give me an appropriate speed for my fingers? Which belts should i use?

I am sorry for all the questions but this is something i really wanted to do for a long time and i don't have the knowledge to do so on my own.

Regards
Bruno

[oklahoma red]

Good score on the parts!. They are a big part of the equation, especially the spring loaded idler.
Several people on this forum have built their own slack sanders and can most likely contribute more than I.
That being said, if I had the 2 pieces you have, I would do it this way:
Choose the belt length first as it will determine the distance between the drive pulley and the spring loaded idler. I would select a 2" (50mm) width with a soft, flexible cloth backing. Others here can give more input on the belt specs/sources. I would make the belts as long as possible (economically and practically speaking) as that improves the ability to work the belt into tight spots.
If the room were available I would mount the upper idler to a rigid wall, perhaps with a spacer block/arm of some sort to hold it away from the wall depending on what angle I want the belt to be (vertical or tilted back).
I would use a motor with a variable speed drive and use a coupler to mount the rubber drive wheel straight on the motor shaft. This will enable the belt to be slowed to a crawl if I so wanted. I would mount the motor to some sort of wooden or metal plate which in turn is bolted to the floor. I would make some sort of provision to allow adjustment of the motor's position in order to get the belt tracking properly.
I would build a plywood box that would surround the drive pulley along with perhaps a third of the lower part of the belt. I would cut a hole in the lower portion of the box to accommodate a hookup to a dust collector. Another smaller hole would, of course, accommodate the motor shaft.
If a VFD were out of reach then I would use a step pulley on a jack shaft that will allow speed changes.
Hopefully, you will have more input/ideas from other forum members
Good luck with it all!

[pmbattles]

I am just finishing up my own slack sander. From what I have came across 2x72 is by far the most common belt size and they are really affordable. Go with a J backing or JF (J-Flex) backing. This is the softest backing they make for sanding belts, I believe it is Egyptian cotton. Mine actually came in today and they are extremely soft and pliable. Here is a link to were I got mine, they are only about $2.50ea. I got a 320, 400, and 600 grit...from what I have read on here you only want to use it for finishing and tweeking, not shaping.

https://trugrit.com/index.php?main_page ... a3cca3827e


Here is another handy site. You can put in your pulley sizes and rpms to calculate things like; belt size, gap distance, and belt surface speed.

http://www.blocklayer.com/pulley-belteng.aspx


Hope this helps.

[dogcatcher]

You have the makings of one of the sanders on this link. Scroll down about 2/3's of the way. http://www.shopsmith.com/ss_forum/viewtopic.php?t=10157

I made one like it, used a 2x4 mounted on the wall, with big L brackets holding the wheels out from the wall. Then used pulleys and a jackshaft to adjust the speed.

[brurobas]

Thank you for the answers guys!

I am trying to explore every options since i wanted to use pieces i already have.

Do you think it would be possible to mount this idler stand with wheel on the floor instead of on the wall? I would use a smaller contact wheel connected to the motor on a top position.

[sandahlpipe]

I have a different sort of slack sander. What's important is that your wheels are slightly domed so the belt will track, and that the wheels your belt runs on are co-planar. Everything else is however you want to do it.

[LatakiaLover]

What Jeremiah said. If you can, disassemble that metal pulley and turn the contact surface so that it's both smooth and slightly domed (radiused) so the belt will track (self-center). Trying to use it as it presently sits will drive you crazy trying to get the machine to run properly.

If you don't have access to a machine lathe, take it to a shop and have a pro do it.

[pipeguy]

both wheels should be about 2" 1/4 hp at 1700 rpms
viewtopic.php?f=9&t=8295

[brurobas]

Thank you for all the answers guys.

As i said i wanted to use stuff i already have on the workshop as i am not that handy in buildings complicated structures and it is very hard to find anyone who can do it for me and the ones who can are ridiculously expensive.

Today i started to mount the setup and this is how it is looking right now. It's not very pretty but i already started it and it worked exactly how i wanted it to. Now i need to bolt and tighten everything up and start using it.

The drive wheel is 2.5'' and the contact wheel is 5''. I am not very worried when it comes to SFPM because the rotation comes from a BOSCH Pillar which has 1 HP and electronic variable speed connected to a shaft which serves as support for the drive wheel. I know, it's very VERY crazy but it works!




Sweet Smokes
Bruno

[Pkspecial23]

Looks cool! Nice job diy-ing it.

[RayMcDaniel]

That is great.