Does anyone use one of these or similar - to true the body?

[Tarhead]

A concern I have is the stress you are placing on the Drill Press. You can ruin the spindle bearings if you do that for extended periods. Small loads and short periods (ie: Luthier's Friend type spindle sanding) no problem. A whole guitar side would push it too far I'm afraid.

[deadedith]

You may be right. I was leaning toward a spindle type sander. Would that be better?

[tippie53]

Very good point . When I am sanding the warp out of a side I use my belt sander . You can use almost anything that has a wide straight edge . Never get aggressive with a sander just let the sandpaper do the work.

[David L]

I hate to be one to jump on the no-go bandwagon but it seems to me (based on that last drawing that you showed) that the outside radius of the body (upper & lower bouts) would always extend further into the drum than the stops would allow and of course with that last set-up that you showed you wouldn't be able to an inside radius such as the waist. Before I started building guitars (plural since I have officially started my second) I built a knock-off of the luthiers friend (before I even knew what a lutiers friend was) and it looks similar to the second drawing that you showed but with a fence added so that I can feed small stock (binding type sized material) into to thickness sand and while I will say that it does work, if I hesitate on my hand fed feed rate it sands a nice ugly gouge/low spot in the material. Someone correct me if I'm wrong on this, spinning sandpaper and spinning hardened tools act differently insomuch that there is always some give or a certain amount of flexiblity with sandpaper and/or the tools that it is mounted on making accurate delicate work difficult. I'm not going to tell anyone that they can't do anything, I do lots of stuff that is probably "not" reccomended, these are just my observations (whatever they may or may not be worth).

David L

[deadedith]

David L - I agree that the radius of the sides would extend further than the stop, but I don't think that's a problem because you would adjust the stop to allow for that. At least in my head, that works. :-) And sure, the stop or fence or whatever would have to be shaped close to the spindle to accommodate curves - again, not a problem. As for shaft wobble, the stop would also prevent the spindle from exceeding the limits you would set

So, still playing with ideas - if you start with a rigid shaft (:-)) , and expose only a very very small portion of it, and have protection in place so that it is impossible for the shaft to exceed the protection and for the sides to exceed the protection, what danger could there be? You could not sand too deep. If you stopped your feed, it would not sand any deeper.

Still, if the answers are all unanimous against the idea, I am going to have to really re-think it. I appreciate the responses.

[David L]

Oh no, no re-thinking, you must carry through with this, because if it works I'm going to steal it. The more tools I use, the better I do (usually).

David L

[tippie53]

You have no way to really control the side and the depth of removal. There is a good bit of flex and you can over sand in a hurry and You can still sand through the sides. You shouldn't be thicknessing a side after it is bent , just trueing it. You need to let some thickness to allow for the sanding process .
The is a difference with the way the routing fixture works and what you are trying to do. If you change a feed speed you can put a ripple in the side. Call me , maybe I am not understanding what you are trying to do.

[deadedith]

Really what I am talking about is not much different that what JohnParchem described earlier, except there would be a safeguard built in. This is for truing, not thicknessing.

[Darryl Young]

Dave, it appears there is no "absolute reference" to prevent you from taking the side down thinner and thinner with each pass. With a tool in hand you can feather into and out of the sanding operation so you can get by with it (and can also mess things up if you aren't careful or if you ever stop in one place). Using the foam on Ken's tool with his design, the foam will spring you up and away from the cut. This wouldn't be the case with a long sanding spindle. I think it would be difficult to keep the sides parallel to the sanding drum while rotating the body. Just my thoughts.

[deadedith]

Darryl - you may be right too. I do think though that since the 'stop' around the spindle is the same height as the spindle, it would actually be easy to hold the body against the stop and keep everything lined up perfectly. Also, I have to think it would be more accurate and less dangerous than the hand held job.
I need to do a mock-up to show you what I mean, I think. I haven't expressed myself too well.