Radius Sanding Blocks

[Woodenspoke]

I thought I had run out of tools to review but I have more.

OK the never ending radius block discussion. Make my own or buy.

Radius blocks are used to create or final sand the arch on the fingerboard using peel and stick sandpaper. These do not work with compound radius fret boards. Very useful if you can use them.

All of these blocks came sanded but unfinished.

StuMac

These are nicely made blocks easy to handle and seem accurate. The fit and finish is as good or better than my homemade blocks. They are single sided so you get one radius per block. They are made from hard maple so should last a lifetime if treated properly. The size is clearly stamped on the edge and is visible from a distance. These blocks are 8" long and 2 3/4" wide and it is sold in several sizes.

LMI

This block is 12" long, also has a double sided radius and is very wide at 4". You ca see it dwarfs the SM block. Probably the widest blocks sold that I know if. However they are made of a softer hardwood than the StuMac, Poplar. They are harder to hold with one hand even for my big hands. They seem accurate and well machined except for the ends which are somewhat rough. The stamped radius sizes were hard to see so I used a sharpie so I didnt need to strain my eyes to see what radius it is.

Home Made

I threw these in just because I figured I would let people know I have made my own tools on occasion. I used the Wagner Safety Planer method and lots of sanding and checking. Not really easy to make if you want a full set of standard sizes. I doubt that these are very accurate compared to the others. I now use them as a caul for gluing in fret wire so they have not gone to waste. made of White Oak.

Conclusion

I like the fit and finish of the StuMac but you have to buy individual blocks for each radius. The other draw back is again with wide fingerboards like a 6 string bass. I don't think 2 3/4" will cut it at the lower fingerboard on a 6 or 7 string bass. Any other build should be fine. The LMI could have been better especially with its fit and finish. I love the long length and wide radius but wish is was made of maple every time I pick it up. I don't think in the long run the wood type will make any difference as they are both stable hardwoods. that is unless you want to use the LMI as a clamping caul (not recommended).

Both Suppliers provide blocks in different sizes, for new work always get the longest you can afford. If I had to choose only one it would be the LMI as the double sided radius, extra wide profile and long length is the bargain of the two. At only $4 more than the SM its only $10 per radius VS $16. I am a tool freak so it would be hard not to have both because the SM blocks come in a greater variety of radius sizes and can be clamped without fear.

SM does make an Aluminum Radius sanding block which I do not own, and at $130 a pop never will. The only drawback I can see with this is they didnt make it wide enough either for a 6 or 7 string bass. I guess they don't believe in wide fingerboards or don't follow market trends.

As for making your own be my guest. The longer they are the more useful they are, but this makes them more difficult to make. If someone has a fool proof method of making wood blocks that does not involve sanding, making specialty jigs for a router, or buying custom profiled moulder planer blades let us all know. At some point $20 should not be a hardship, and we all know how expensive this obsession can be.

Both of these supplier made blocks were coated with Shellac to keep moisture to a minimum.and keep them stable. They did not come with a glossy finish. I expect to have to re coat this finish over time as they get messy from the Sandpaper glue cleanup. One of the reasons I did not use a slower drying poly.

[jmrentis]

I have a couple of the stewmac blocks and so far have been pleased with them. I did look around before buying and felt the stewmac one was the way to go, but cost wise the LMI one is a bargin, but personally I wouldn't want poplar. I got a neck support caul from Stewmac that was poplar and when gluing up a fingerboard on a shaped neck the thing busted and shredded something terrible. It definitely wasn't meant for any clamping or anything obviously, but I do like using the radius blocks and such for glue ups so actually the stewmac would make a better price for me since it has multiple uses, even if only one radius. As you I coated, I had some unused west systems epoxy and just threw it on there and actually I love it because it gives me an ever better grip and looks like this nice gloss finish, lol.

Anyhow the reason for my post was a block that I didn't get to try, but I was curious about. At OLF they have an auction site that people often sell stuff at like radius dishes and such. Here and there a person sells radius blocks and I believe they are much closer to the size of the LMI block, but made of hard maple. The price wasn't too bad either if I recall correctly. I didn't need one at the time so I didn't get one, but I may in the future, as long as the person still sells them. There is none posted now, but if anyone has tried one of these or has heard anything I'd be curious. As I said, they are longer than the stewmac by quite a bit I believe and wider and made of hard maple. Not sure if the person does a double sided deal or not, but its possible. Anyhow, just a heads-up on that block. Thanks for another great review.

Quick question: I know you mentioned stick and peel paper, I've just used some adhesive spray like 3M special 77 or something similar with my normal sandpaper and never had any problems, but I was curious if there is a reason to choose one method over the other, such as any possible problems or anything? Thanks for the help. J

[Rick500]

If someone has a fool proof method of making wood blocks that does not involve sanding, making specialty jigs for a router, or buying custom profiled moulder planer blades let us all know. At some point $20 should not be a hardship, and we all know how expensive this obsession can be.

I'm thinking that my router radiusing jig would work to make radius sanding blocks, with a sled with the opposite curve as in the pic. In fact, I think I remember someone here saying they'd made blocks that way.

[Woodenspoke]

Quick question: I know you mentioned stick and peel paper, I've just used some adhesive spray like 3M special 77 or something similar with my normal sandpaper and never had any problems, but I was curious if there is a reason to choose one method over the other, such as any possible problems or anything? Thanks for the help. J

I guess it doesn't matter what you use as long as it works. I happen to have a boat load of peel and stick from Klingspor sold in a bargain box. This should last a life time. I remove the paper when I am done since I have so much, plus its shot after one use. I guess epoxy sounds like a good idea except I only have the 5 min kind and thats pretty thick. I forget what thins epoxy off the top of my head?

That OLF block sounds sweet, but do I really need another block....thinking.....I want it.. ..guilty feeling coming over me.....biting lip.....Ugh, reality sets in.

[anderekel]

Another great review, and finally something I already have so I don't have to go out and get another, or do I......

I have Stewmac one, unfortunately I go a bad one, but didn't think to send it back and it's WAAAYYYY too late now. It's got some ridges runnin' down it, I'll get rid of'em when I actually use it, but yeah.

Rick, that's a good idea, and after making the initial radius I bet it wouldn't be too hard to make multiple and maybe sell them to friends online..... :D

[soapbarstrat]

What I really used to hate about spray adhesive is that I would have to breathe the damn stuff, plus it would stick too well to the radius block and be a lot more trouble to clean off when you changed sandpaper.

I only use radius blocks for roughing in a radius (including compound radii- 4" or shorter blocks for compound), and finish with a narrow flat bar on the fret-board wood. I stopped using wood radius blocks to level fret tops long ago, because the precision just ain't there. I mean they're *wood*. Just like I wouldn't make a fret-leveling beam out of wood and trust it 6 months later to be precise. If your wood radius block ends up with a twist or hump or dip, you're probably going to transfer those types of imperfections into your fret-board sanding. You can check some of their accuracy with a straight-edge and precise reverse radius gauge (like an "under the strings" radius gauge). I guess checking for twist is harder and I don't want to go into ways I think one could check that.

[Kenny]

If someone has a fool proof method of making wood blocks that does not involve sanding, making specialty jigs for a router, or buying custom profiled moulder planer blades let us all know. At some point $20 should not be a hardship, and we all know how expensive this obsession can be.

I'm thinking that my router radiusing jig would work to make radius sanding blocks, with a sled with the opposite curve as in the pic. In fact, I think I remember someone here saying they'd made blocks that way.

i could take pics of my jig

i make my blocks that way:-p

i have a few blcks lightly longer and wider than my board that i made

vs my stewmac one they are just as accurate, and almost as smooth. i rather use the ones i make

[Woodenspoke]

I only use radius blocks for roughing in a radius (including compound radii- 4" or shorter blocks for compound), and finish with a narrow flat bar on the fret-board wood.

A long sanding beam should be the final step in leveling a fingerboard as Soap points out.

I stopped using wood radius blocks to level fret tops long ago

Good point.

I guess checking for twist is harder

Using winding sticks should work for a twist or laying it on a known flat surface and see if it rocks back and forth. Both of these methods should send up a red flag.

Some of you may have noticed I did not mention that I had checked these blocks with my reference straight edges. I haven't. This is one tool where sighting down its length and checking its fit and finish should be good enough. If its way off you should see it right off as Anderekel found out.