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Hi Folks

Is there some way to set up a open ended drum sander to produce even sanding across the full width of the belt?I am having mixed results and they are mostly all over the place depending on belt drive speed and material.Any help here would be great and much needed .

JJ

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"Practice enough till the results aren't hopes but expectations" forum member Peter Havriluk

Which sander? I have a jet 22-44. I have to adjust it level every now and then. I never got the need for the speed adjustment I go full speed all of the time. I only take a very little off each pass. I use 80 grit for the most part, sometimes 100. Also I put though each piece flipped side to side and end for end with sequential passes. When working with hardwoods, I make multiple passes without adjusting the thickness knob. It is too easy to get ahead of the sander ability to remove wood,

WIth all of that my pieces measure flat when I am finished.

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http://www.Harvestmoonguitars.com

I have a Performax 16-32 and I follow the setup instructions shown below to align the drum. I follow their recommendation to set the outboard end of the drum slightly high and get good results. Even if you have a different sander than mine, the setup principle is probably the same or similar.

When using the sander, I do exactly as John recommended above with light passes, flipping end to end and side to side, and I finish with multiple passes without touching the adjustment knob.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

Got to love the help you get from this forum!

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

I have a Ryobi, and it uses shims on the outside of the unit where the sanding bed attaches to the base.

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Pat

Accurate set up, very light cuts, low speed feed, fresh abrasive. Trying to hog off material will hinder the accuracy of any machine of this design.

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Ken Cierp

http://www.kennethmichaelguitars.com/

It probably goes without saying (but I will say it anyway): If you have a cantilevered sander that is wider than the tops and backs you are building, then as long as you get the drum close to parallel to the conveyor, a little variance is no big deal. If, on the other hand, you are using a sander that is narrower than the tops and backs you are building, and you need to tilt the drum to avoid the ridge in the workpiece that can occur at the end of the drum, then that requires a bit more attention. People do it successfully, so no worries if you are in that situation, but you need to follow the instructions in the manual. The Jet/Performax instructions (shown above) are what I used when I owned a sander like that (a 10-20).

I will say that I prefer not having to deal with that, now that I have a larger sander that is also not cantilevered. Like I said, it can be done, and people do it, but I prefer not having to worry about it.

Jonny - As you have likely surmised, the short answer is "No." Thankfully, as Don points out, all is not lost!

These machines can be set up to get you very close, but to get the most uniform results possible across the entire plate you typically need to run the material through multiple times at opposite orientations. I have the smaller Performax/Jet 10-20. I set it up and run it precisely as Jay illustrates and operate it as John describes, although I don't run the feed belt at 100%. I don't know what Ken considers "slow" but I typically get the best results at about 75% speed. Anything less seems to encourage burning and/or buildup on the abrasive belt.

Approaching the process in this manner, I achieve perfectly acceptable results. Multiple light passes is the trick, in my opinion.

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George :-)

I would guess that most builders end up with a tapered top where the center is thicker than the edges. I always did. That said, I had my 16/32 Jet set to taper the material by .004-.008". Not necessary to get an absolutely dead flat top, back or even ribs.

I had to adjust mine (16/32) to be level when I first installed it. At that time I was building 00's and Uke's. The soundboards and backs just fit without over hanging. This fall I'm building my first dread. Looks like I'll be doing the shim trick from the manual. Good timing on this thread!

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I use a sled. It's easier and more accurate than fooling around trying to get the drum parallel with the bed. The sled gets trued up every now and then by running it through the sander and attaching a new fence.

Great idea for perfect leveling. I'm being a little dense on the fence though. Could you explain what that is?

I will bet the fence is a board on the back edge of the sled to keep the workpiece from slipping off. It probably gets sanded away when resurfacing.

Yep, I'll bet that is it. Thanks Barry! I knew I was being a little dense

I have a Performax 16-32 that I can usually get within .003" inside to outside, with the larger gap to the outside. Once again, light cuts and quick passes works best.

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A man hears what he wants to hear, and disreguards the rest. Paul Simon

Not my idea or photo but I did something similar to this on my Ryobi when I had it:
The inserted photo shows how Steel City Tools packaged their version after they bought the tooling from Ryobi.

I have several sleds for sides, 1/2 tops/backs and full width (16-32). I used old belts contact cemented to them so I don't need a fence. Be aware to keep the sled traveling through the sander in the same direction each time.

When the sander gets periodically adjusted sand the bottoms of the sleds to reestablish the flat plane.

Another factor is how the sandpaper attaches, sometimes leaving a bit of extra material causing a raised spot at the attachment point. One has to be careful that the paper is flat on the roll at the ends where it attaches.

As the sander works the paper tends to shift, causing the bunching effect at an attachment point to worsen and dig deeper into the wood being sanded.

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"Building guitars looks hard, but it's actually much harder than it looks." Tom Buck

That is actually the trickiest part for me, although using some gooseneck needlenose pliers to stretch the paper at the attachment points helps.

Because of the rotation direction, the open end stays tight for me and the attachment at the opposite end doesn't lay as flat as I'd like even with the spring take-up.

When sanding tops, I watch how far I insert the top towards the closed end to avoid that flap.
Mike

I may be slow today but I do not understand. If the drum is not parallel it seems that you would need to level every time you lowered the drum a bit. When loose for lowering the drum what keeps it parallel?

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http://www.Harvestmoonguitars.com

I deleted this comment, because I realized John P was asking a different question than the one I answered which rendered my answer irrelevant.
Mike

Exactly, I should have been more clear.

What a good idea! I've been using a little piece of wood to push the sandpaper down while I hold the locking device (impossible to describe I know).

You first shim the base of the conveyor to have the drum parallel with it. Then as you make your final passes you lock the open end to prevent it from flexing.

Thank you, I understand now It is to deal with the flex of a properly set up sander. A very good idea.

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