HowTo Make a Wooden Radius sanding block

[Dave Warner]

A very handy lutherie tool is a wooden sanding block with a set radius on one face. You can see an example at the Stewart-MacDonald site on this page.

I'm aware of various jigs/methods to make these on an individual basis. However, say I wanted to produce them in quantity. What would be the preferred method?

I was thinking this seems appropriate for a shaper and some custom tooled cutters, but having never used a shaper or commissioned custom tooling I do have some doubts.

What do you guys think?

[Chris Padilla]

Shaper, appropriate knives, and a power feeder.

[Josiah Bartlett]

Depending on the radius you want, you could do the cove molding cut method on a table saw. I think that would be the cheapest.

[Brad Shipton]

Do you have the items you need to sand? If so, you can make the sanding blocks using fiberglass resin. I just made a few a couple nights ago to sand some railing. Take some scrap (assuming you have some) whatever length you like for sanding and make a box to go around it. I applied a bit of spray and some wax paper to the surfaces. Dont use plastic as it will not stick and tends to bunch up leaving you a wrinkly surface. Apply the same to the part. Fill the box with resin and in a few hours you will have an exact piece that you can screw whatever you want to for holding purposes. Piece of cake if you have the part. $14 in resin at a hardware store and I can make quite a few.

Some use spray foam, but then you would need a top and I dont think it will hold up very well.

Brad

[Ryan Baker]

1) Buy a CNC machine.
2) Use a moulding machine with a custom cutter.
3) Use a Wagner safety planer at an angle in your drill press, as long as you don't mind the very slight difference between the parabolic shape it creates and a true radius.
4) Build a swinging-arm router jig. There are designs on lots of sites like projectguitar.com or mimf
5) Have a custom router/shaper cutter milled and build the some fences.

etc.

[Rod Sheridan]

As Chris indicated, a shaper, power feeder and custom knives.

Yes, HSS knives that are ground to the radius you require.

These knives are held in a cutterhead tall enough to cut the entire radius profile in one shot.

Then you just cross cut them to length.

Look up custom tooling in your area and give them a call.

Regards, Rod.

[Jim Dunn]

Depending on the radius you want, you could do the cove molding cut method on a table saw. I think that would be the cheapest.

I agree. Plumb simple. In fact page 60 of Woodworkers Journal October 2003 (Volume 27 Number 5) has an excel formula for all of your cove cuts.

[Vic Damone]

Why bother? They're cheep enough. I have a 7 1/2 (I think) that I used to level the rosewood cap on my 63' Jazz Bass neck after defreting. Once again after applying a coat of epoxy to the fingerboard. I doubt I'll ever use it again.

[Brad Shipton]

I'm not sure how many of you have bought custom shaper blades, but I have several times now and they are expensive. Anywhere from $30 - $50 per inch per blade plus programming time. The last pair of customs I had were $200 per blade (3" profile) and a set before that were around $300 each. The process to make customs involves first making a hogging template and then programming into a $60,000+- grinder. Weinig has a video on their site showing them making sets if anyone is interested to see the process. I know some experienced woodworkers that can grind their own in softer steels, but that is a skill I do not have. Old Dusty on FWW can fill you in on that one.

If you dont have the raw stock to use for a mould, then I would either use the table saw cove trick assuming it is a simply rad or get out some hand tools and shape up some parts if you can warrant the time.

Brad

[John Schreiber]

A shaper, a power feeder and custom tooling is the obvious, and probably the right way. I get the feeling though that you are looking for another approach.

I could imagine doing it with a shaped sanding drum attached to a motor and a table. Here's a quick picture.
sanding ball.jpg

The curved shape would have to be hand made, probably on a lathe. Sandpaper could be attached using either Velcro or an adhesive.

Not sure it would work, but it's a lower budget way of getting there.

[Jack Briggs]

This is one instance where I'd vote for CNC. Don't buy a machine, hire out for the work.

A shaper and custom cutter seems to make sense but your stock would have to be absolutely square, flat and true. CNC negates these necessities.

For an established CNC shop this is a very easy job for both programming and execution.



Cheers,