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Discussion Starter · #1 ·
I'm thinking about making a drum sander to help with thicknessing instrument backs and tops.

I see some people say a manual feed is bad as if you slow down /stop it will create a groove. I don't really understand why this would happen though, isn't the concept that the sandpaper can only reach down to the depth you want to achieve?

Also can anyone tell me how much faster I could expect a drum sander to work for me than hand planing? I do re sawing myself so it's not like i'm working with material that's already close to its final thickness, I sometimes might get stock thats 6-7mm than I need to reduce to 3.5. Hand planing seems to take a long time.

I don't think id have a problem with using something like 60 grit and then manual sanding or planing with smoother to get the final smoothness.


Thanks
 

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Not a good idea if you are making a drum sander where the drum is above the table. You will get a very uneven surface. :thumbdown:

The above the table drum sander applies pressure on the wood. If the feed rate is not exactly consistent you will get more sanding in the areas where the drum has more rotations.

I have a Performax 16/32 drum sander and have experienced this issue is the feed belt slips underneath the wood.

If you make a below the table drum sander, like the FlatMaster, this can work, since the drum does not apply pressure on the wood. I have a 30in unit.

A recent thread with a review of a 24in unit.
http://www.woodworkingtalk.com/f24/24-inch-flatmaster-v-drum-sander-58966/

I do not know if the kits are available in the UK.

I would not recommend a FlatMaster drum sander for the thin pieces you need for your instruments.

A normal above the table drum sander can do thin pieces, perhaps 1/8in if you use a sled to hold the wood to prevent the feed belt from touching the drum which will wear out the abrasive on the feed belt in a few seconds. I experienced this issue.
 

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Discussion Starter · #3 ·
Thanks.

The above the table drum sander applies pressure on the wood. If the feed rate is not exactly consistent you will get more sanding in the areas where the drum has more rotations.
This bit I don't quite understand. Isn't the goal to have the sander sand as much material as it can without the table height being raised? Thereby creating a uniform thickness which = the distance from the table to the sanding drum?

I'm sure you're right in what you say but why does stopping the material being sanded have any influence over the distance being sanding i.e. the distance from table sanding drum? Maybe I have the wrong idea of how this all works.
 

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I'm sure you're right in what you say but why does stopping the material being sanded have any influence over the distance being sanding i.e. the distance from table sanding drum? Maybe I have the wrong idea of how this all works.
I know what happens when the wood slows down or stops. If the wood stops, you will get a deep ridge in the wood from the drum.

The drum applies pressure on the piece since the distance between the drum and the table is less than the thickness of the wood for a given pass.

When the wood is moving the drum does not take off all the potential wood from the pass. When the wood stops, the drum is able to take off more of the wood.

Build you drum sander with manual feed and you will observe the situation in a single pass.
 

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Discussion Starter · #5 ·
I think I will probably build a conveyor in now. Probably powered by hand crank and then upgraded later on.

When the wood is moving the drum does not take off all the potential wood from the pass. When the wood stops, the drum is able to take off more of the wood.
What if you were to run the piece through again after you'd made the ridge, would it not eventually flatten out to one consistent thickness?
 

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What if you were to run the piece through again after you'd made the ridge, would it not eventually flatten out to one consistent thickness?
Sounds easier than it has been in my experience. When I have ended up with a ridge, I had to take off more wood to get the surface somewhat even.
 

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For what you are trying to do I would build a Flatmaster style sander with the side wings from Stockroom Supply. The wings will allow you to apply a light even pressure as you push the projects through, which will keep the thin pieces from flexing so they will come out flat. One of the problems with regular drum sanders and thinner pieces of wood, is the wood flexes from the pressure and, if the piece is not flat, it will come out exactly the same way, not flat. With the Flatmasterlight, using light pressure, the piece doesn't flex but it will still sand when you push it through, so it will end up sanded flat. That's why they call it the Flatmaster. The Flatmaster is not good for everything you will sand but if you want to sand pieces and have them come out flat, it does a great job.
 
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