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Thanks, Nelson.
Pretty impressive precision requirement.
I wonder what the sandpaper thickness variation is, when doing this sort of work (paper stuck to levelling block).

Cheers
John

I suspect that a tolerance of .0015" is fine for most of us, but he does list his "Premium Reserve" sanding beam as having a tolerance of less than .0002".

http://cgi.ebay.com/Quartz-20-SANDING-B ... 4aa446e6ac

Alan, thanks for the heads up. Got one on order.

John, you're right in that the sandpaper alone varies and I would guess by a couple thou at least.

I like the extra precision in that it can also be used as a master flat surface for the shop.

Best regards to all.
Nelson

I assume that you are freehanding the radius on the belt sander?
I've found that to be much better than using a radius fixture.
Nelson

Silly question..... but how do you create a radius with a tool which has a flat surface?

You gotta be kidding me...but then I thought, Ya know Padma, there are some out there that really don't know, so get off your high horse and answer segovia.

Elbow grease...

the sand paper will cut and remove the wood.
so its ...back and forth with that sanding beam,
push and pull.
Is called elbow grease, a few passes and you will see the wood turning into sawdust.
More pressure on the sides and low and behold it starts to round over. Eventually with enough elbow grease (back and forth passes) the fretboard will be "sculpted" or radiused to what ever curve you wish.

back and forth
push and pull

Simple eh!

Sorta like "wax on, wax off."

Secret tip...let mind go blank while singing a silly little song like....
"Rounding off the fret board,
Rounding off the fret board,
Happily rejoicing,
Rounding off the fretboard."

takes about 8 - 10 min with 120 grit paper, in communion with just you and the wood.

Of course you can make up your own little mantra to imbue your build with.

Anyways the inner feeling you gonna get when all of a sudden you realize the sucker is rounded off can never be taken away from you.

blessings
Padma

_________________
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Audiences and dispensations on Thursdays ~ by appointment only.


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I more or less figured that out but then I thought whats the point in having (expensive) radius sanding blocks if you can do it with a flat block, I was looking for something that wasn't there.

The point is ...its easier.

Now regarding expensive radius sanding blocks...hmmm...

Plane a chunk of pine into the various radiuses you gonna use.

Glue down some sand paper.

Take un-radius blocks (fir 2x4 will work)

Sand block(s) till desired concaved radius emerges.

Cheap like borscht.

Less than an hours time and you gotts a whole bunch of radius blocks.

Simple eh!


It is a sad comment on our western disposable culture that so many of us have bought the BS* that you gotta buy the tool. That type of thinking came in in the 50's. Before that we were taught to think ... "how do I make the tool to do this that or the other." Just another one of lifes "oh wells"

Just look an any old wood working mags and text books from the 50's and older... always an article on how to make this that or the other tool...now the articles about tools are reviews on which be the best buy. Right!


blessings
Padma

* Belief System

_________________
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Audiences and dispensations on Thursdays ~ by appointment only.


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Well I ended up going with a 16" radius using the LMI block, with a few dots of Elmer's glue to stick 60 grit garnet paper to it without soaking it in glue that would be hard to clean off. Then hold 100 and 220 grit against that to smooth out the scratchies, and finer grits by hand. I admire those of you who radius entirely with a flat block. That would be quite difficult to get a similarly smooth curve. Plane I could probably do, but sanding goes so slow it would be hard to keep track of. And my love of inlays = plane not so good.

The convex block to make concave block technique would have been good too, but I hadn't considered making my own concave block before buying one. And now I figured sending it back and then making one like it would be mostly stupid. Just gotta remember to think it fully through next time before I go clicking those fun "spend money" buttons

So to answer my original question, "Put a couple dots of Elmer's on it for the shaping grit. Hold smoothing grits against that." But all the perspectives offered in the thread are great to know and have documented for future generations of radiusers. Thanks everyone!