Making a Drum Sander – Part 2 – Tilting Table


I took Sunday off and on Monday I had other things to do but yesterday and today I could work on the drum sander some more and I progressed significantly. First I finished and attached the propulsion wheel. I started that right at the beginning but it progressed slowly because I glued it from several layers of old plywood and I had to wait for the glue to dry a few times. Just before the two-day break, I soaked the surface with epoxy resin to make it harder and on Tuesday I turned and sanded it until it was passably round. I will probably give it another layer of epoxy once everything is finished, I will use the epoxy on other parts too to improve their surface hardness and strength.

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The wheel is attached to the axis with an M4 screw going through a thread drilled and cut into the axis. I hope it is strong enough and won’t get sheared off in work because I do not have any better idea how to do it. I need to be able to eventually remove this wheel in case a ball bearing gets busted and needs replacing. I am also leaving myself a bit of the axe poking out so I can power the thing with my drill in case powering it with the belt grinder does not work.

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On the right side, I added a fence with a shelf to lift the base 55 mm; on the left side, I simply added a 55 prism. Then I screwed two spruce boards on it to reinforce the structure. Though I screwed them on with the wrong grain direction of the core but it seems to hold strongly enough. Should a problem occur, I will reinforce it later or replace it with properly oriented boards.

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The base under the propelling wheel is unsupported. This has a reason – I need to be able to slide this side over the base of the belt grinder because I need to align this wheel with the motor and the spanning wheels of the belt grinder. It should not be under too much stress but I did reinforce it with steel under the wheel where there will be most of it. Again, I might add some more support later, for now, I think this suffices.

That was Tuesday done. I attached it improvised to the belt grinder and it worked, albeit it was loud as hell. I think that can’t be helped, the ball bearings are not perfectly aligned and the drum is not concentric yet and I can only solve the second of these two issues.

Today I made the tilting table to adjust the sanded thickness. And here I must thank to rsmith for pointing me to a page with useful information about how to make a very simple one.

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I started by cutting-out a piece from the lifted base. This was the plan all along, to use this space for some sort of mechanism to lift the table. On the front, I added a 55 x 20 mm beech board across. Beech is reasonably strong hardwood, it should be able to support the table. In the middle of the board is inserted a 24 mm long M8 nut with a sufficiently long rod through it. To operate the screw I tightened on it a hex nut and a winged nut against each other.

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I decided to make the table from a 15 mm particle board because the piece I had had a very smooth surface and it is straight. However, particle boards are not exactly known for their strength, so I had to reinforce it. I reinforced the rear end with stripes of beech wood for the hinges to have better and stronger anchor points. I put it under weight and went for lunch while it was setting

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After lunch, I continued reinforcing it. On the front end, I added an offcut of angle iron. That also provides a hard surface for the screw to lift the table.

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For longitudinal support, I screwed on two beech strips. I forgot the exact measurements, somewhere around 25×15 mm or somesuch. I tested it and it seemed to be sturdy enough against bending, but not against twisting due to the table being supported by a single point on the front. It should not be a huge problem if the sander is loaded in the center as it should be, nevertheless, I decided to reinforce it further with three offcuts from the same particle board intended for firewood.

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One continuous piece would be better and I had a suitable one – the one that I cut out of the base in the morning – but I completely forgot about it until these were screwed on and I did not want to go through the hassle of trimming it and drilling all the holes again. I think it is strong enough and if not, I can add more support later. I say that a lot.

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And this is where I finished today. I think the work is progressing nicely. I have a tilting table with a range of about 35 mm, which is plenty for my purposes. It takes about 80 half turns to lift from zero to full. That is enough sensitivity to sand off only tiny layers of material when needed. The whole assembly so far is sufficiently light and compact that I can easily lift it and put it under the table next to the table saw when not in use. I am reluctant to be optimistic but I do feel ever so slightly positive about this project.

Comments

  1. says

    Looking good!

    Changing the moveable table to a box section is a great idea. A closed box section withstands twisting very well.

    Using a screw to fix the wheel should be OK. If the drum does get stuck, ideally you want something that’s easily replaceable (like a screw) to break.

    If you can get some, bonding a thin layer of HPL (aka “Formica”, “Getalit”) on top of the table would help the workpieces sliding over the table. A thin sheet of metal would also do the trick.

  2. flex says

    Nothing to say other than this series of posts is fascinating.

    I’m looking forward to hearing the goods/bads once it’s in use.

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