Drum sander project (work in progress)

[mreza Salav]

I have been collecting information and reading different plans on building a thickness (drum) sander. I felt the need while working on my previous project (the bed) and how it could have saved my time and a lot of wood. It is going to have a power feed conveyor.

Anyway, the initial plan of an 18" wide one has grown to a 28" one. I've got almost all the parts (including the DC motor for the conveyor).

First, started building the rollers for the conveyor as well as the drum. First cut a lot of disks (out of plywood) for the drum. Then cut many disks (out of BB ply) for the rollers. They are not quite a circle in the glue-up but that's Ok. I made a jig (to be used with router) to make the rollers perfectly round (to less than 0.005" variations). The shaft for the drum is 3/4" and for the rollers are 5/8". Once the disks are also glued (together and to the shaft) they will make an even stronger piece.

The disks for the drum will be glued together and to the shaft. There will be also 5 cross sectional 3/16" thick pins that will go through the shaft. The groove in the disk (shown in the 2nd picture) is to receive one of these pins.

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[mreza Salav]

Then I started working on the table and the elevation system. For the table, I used MDF and laminated it for a smooth and durable surface. Then made a platform out of 1+1/4" hard Maple (and a piece of scrap walnut) to support the table. The support is M&T joinery and is screwed to the MDF piece to make a 2" table that is very solid. I fine tuned it to make sure the surface is absolutely flat (according to my straight edge).

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The sides are made out of 1+1/4" thick hard maple. It will house the bearings for the rollers and the elevation screws will be attached to it. I got the screws and the nuts off the e-bay. They are exactly what I wanted: 3/4" ACME screws with smooth ends.

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[John Pahl]

I've wanted to take on a project like this myself. I look forward to seeing the completed project. Please keep us updated. Looks great so far!


John

[mreza Salav]

All the pieces are attached using bolts and nuts (either T-nuts or the dowel nuts) for easy dis-assembly if needed.
The following pictures show the bearing housing and the mechanism for adjusting rollers for belt traction. Each end of each roller can be adjusted by pushing it back or forth using a screw (the horizontal screw in the pictures). It will push the bearing (and so the corresponding end of the roller) if the belt doesn't track properly.

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So, what would be the widest board I can surface sand at the end?

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Thats more than 28" wide. Probably good enough for all my purposes.
The last picture shows the DC motor and the controller. It is a 19rpm with 150lb/in of torque!! I got that from e-bay as well as the controller.
Next step is to attach this under the table.

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[Grady Cowardin]

Very cool. You have some ingenious ideas in there. Hard to believe you got components that nice off re-bay. I figured those acme screws were pilfered from a WW vise. What size motor is going to drive the sanding belt? Chain drive I assume.

[mreza Salav]

Very cool. You have some ingenious ideas in there. Hard to believe you got components that nice off re-bay. I figured those acme screws were pilfered from a WW vise. What size motor is going to drive the sanding belt? Chain drive I assume.

The conveyor motor is a DC motor (as shown above) with variable speed control. It is 19rpm and has 150lb/in of torque. This is like 3 times the one you see on a Delta 18/36 drum sander.

[Greg Cole]

Neat & nice work so far.
What are your plans for height adjustment? Are you going to adjust all 4 jack screws individually or tie them together...?
I've toyed with some ideas on building a drum or belt style sander just can't commit the time as of yet.

Greg

[mreza Salav]

Neat & nice work so far.
What are your plans for height adjustment? Are you going to adjust all 4 jack screws individually or tie them together...?

There will be chain and sprocket connecting all four. I have looked into the mechanism of commercial models (like grizzly) and this is a common technique (for those in which the table moves). I was going to add two drums but thought first try with one drum and if it goes well I can add the second one later.

[mreza Salav]

tonight I installed the conveyor motor and controller and gave it a test run. It runs pretty good. has a very little drift but should be able to adjust it with the traction screws (didn't have time to fine tune it tonight). Will have to add the speed adjustment knob and the label (can be seen in the first picture in front of the table). Also add the main power switch.

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[Dewey Torres]

WOW. Engineering skills to match the WW skills. You made this while thing up? Amazing.
Dewey

[Jeff Mohr]

Looking forward to seeing the rest! Nice one!

[Alan Schaffter]

Nice work so far! Do you have a running $$$ total? I had thought about building my own, but found a decent used 24" dual drum machine for around $500, so I couldn't justify building my own.

Other than buying a replacement for nearly $300 from Grizzly, has anyone found a source for inexpensive conveyor belt material (rubberized, not the sandpaper type)?

[Jerome Hanby]

From one of your pictures, it looks like you covered the rollers for the feed belt with something. Was wondering what you used? I've been toying with the idea of using a bicycle innner tube...

[mreza Salav]

The total cost so far is about $320 without the motor. I am looking to find a used motor (instead of spending in the range of $150-200 for a new one). Even if I buy the motor new, I am happy with the total cost.
Up here, I have never seen a used one this size below $1k.

From one of your pictures, it looks like you covered the rollers for the feed belt with something. Was wondering what you used? I've been toying with the idea of using a bicycle innner tube...

I haven't covered the rollers with anything, but I may have to do so. At a reasonable tension, I can force the belt to slip by holding my two hands down on the belt and pressing hard. I am not sure if that is a typical pressure in real application (have to wait and see the real tests) but may have to cover the rollers. I too thought of covering them with an inner tube, but another idea I am contemplating is to cover it with a very thing layer of epoxy. It seems to give a very good surface for this purpose.

[Grady Cowardin]

The conveyor motor is a DC motor (as shown above) with variable speed control. It is 19rpm and has 150lb/in of torque. This is like 3 times the one you see on a Delta 18/36 drum sander.

I apologize for the stupid question. I thought that motor drove the power feed roller etc. The chain tensioner built in to the mount is nicely done.