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oz tradie

Radius Sanding Blocks Tutorial

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This is another way of making your radiussed blocks in any length and any radius profile using this tool.

The Safe-T-Planer

This must not go unsaid: Not for use in a router.......ever Pedestal drill only peoples. B)

Now, if you've got one of these babies, I thoroughly endorse rereading the safety instructions you got with the planer. Use it as a bible and you may keep your fretting hand intact.

Now this tutorial will show you the steps I took to create a two foot long 12" radiussed sanding block in under one hour. (this time include my set-up,taking photos, cracking a beer and a bit of sanding,too.

I would just like to clarify that this was done on a heavy duty 18" pedestal drill and I was very surprised at how easy this thing was to make. Game on.

The first set up stage is to clamp on a guide fence of sorts. No real mystery there as you want to get a full arc of cut from the blades, but also use the fence as a stabilizer as you slide from right to left with your

'soon to be radiussed timber'. (Is that a hunk of blackwood used as a guide fence? w.t.f.?)

The guide Fence:

DSC03684.jpg

Next is the most important part where , in this case, I'm using a radial drill and I'll be pivoting the workbench on angle to produce a 12' radius cut in the workpiece.

For this, I had a Stew-mac radius block as my template and it was all done by trial and error over no more than ten minutes. A scrap piece is handy to use until you've got the right angle. And finding the right angle is easy if you have radius gauges, or make your own up. Me...........I used the Stewmac block :D

I found my perfect angle for a 12" radius at bang on 5 degrees. (My drill shows increments in degrees.)

And more importantly, the tilt is to the left side downwards, right side up.

DSC03682.jpg

Now, would be a good time to set your depth of cut by offering up the workpiece to the blades and moving the bench to suit. Don't plunge down to change the cut depth The maximum depth for a smooth plane is 1/8" deep, with lesser amounts providing an even smoother result. (For a 12" radius, you only need 1/8" depth of cut overall for a good, fat profile)

And remember you can do alternate passes and take a little more out on each pass.

The shallower the pass the smoother the result.

The first pass:

DSC03686.jpg

Now, back to the first pass. Feed your workpiece from right to left , while being mindful of those huge

blades are invisible when spinning. B)

A nice easy feed is all you need, and you'll find it extremely easy to get a good result providing you keep the workpiece solidly on the bench and against the guide simultaneously.

Just repeat this until you're happy with the last plane. That's it, really.

DSC03687.jpg

And now a few more pics.

A light feed through:

DSC03691.jpg

DSC03694.jpg

As a precursor to making this sanding block I cut a piece of Tasmanian Oak to 2 1/2 feet long

and used the extra 1/2 a foot as a safety device. ( something to hold onto, really)

Afterwards I just cut the excess off and was left with a solid 2 foot sanding block.

after routing the top:

DSC03699.jpg

DSC03703.jpg

All done minus a bit of fine sanding.

DSC03700.jpg

The Stew-mac block in the foreground, with the new 2 foot block behind it. Matching radius. :D

Hope this helps someone, somewhere. Cheers all,

Stu :D

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Cheers Stu - great info!

I converted your linked images to show up, since this is a tutorial and they're helpful to the explaination.

Note to all regarding pic 3 - remember to crack open the VB after playing with your power tools! :D

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That is AWESOME! I read that booklet, and saw that you could angle it to get imprints like this but somehow I didn't even register "I could make a radiused sanding block with this". You are amazing at connecting 2 and 2 to make 4.... hell you just made 2+2=5 in my book!!

Take that stewmac lol.

I do have one question though. It says to run it at 4000-6000 but my drill press doesn't go up that high.

Chris

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I had to admit I got kind of excited when I tried it out for the first time and it actually worked.

Thanks for the links to pics conversion, Setch.

I was aware you could use extra pics in a tutorial, but was loath to go overboard and annoy everyone with too many loading up all at once. :D

Chris, I don't think lack of drill speed will be a big issue. It just means a bit more time on the feed through.

cheers,

Stu

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If you could, oz tradie, give me the radius of the whole disk itself, from the center to the outer edge of the cutter when extended, that would be great. Please be as exact as possible, metric or imperial is fine, and mm would be great, as it's a closer tolerance than most imperial rulers.

If I have that radius, I can whip up some hyberbolic functions and find the angle needed to produce a cuve that would fit onto a circle with given those given radii (7, 12, 14, et cetera). I can then also give the margain of error, as it cannot be perfect due to the elliptical shape that will be produced from an angled circle.

Please excuse any bad grammar or spelling mistakes, I just woke up!

Thanks!

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If you could, oz tradie, give me the radius of the whole disk itself, from the center to the outer edge of the cutter when extended, that would be great.

You can get a 70mm width of cut, so radius would be half that.

The exact thickness of the stew-mac blocks, funnily enough. :D

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Question for the more math minded: is this actually a circular radius you're getting, or is it actually an elliptic shape?

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Question for the more math minded: is this actually a circular radius you're getting, or is it actually an elliptic shape?

There is no doubt at all that it is technically an ellipse. As you turn a circle( in this case the safe-t-planer)from being on edge,

to front on, it goes through a dramatic change in shape.

Pretty much from dead flat , to varying degrees of elliptic contours until you are face on to the circle.

Now this is the interesting part. How close is it to circular at a 12" radius is something the maths-heads can

work out. :D

Matttheguy seems pretty interested in running some sums for us.

I also wonder how much change to an ellipse is also governed by how 'front on' to your angled cutter you

are? ie. if the cutter is angled 5 degrees toward you, but you take a slight cross-angle to it, I would bet that would also change the ellipse as well.

I'm curious as to how close it will be , as I really can't tell the difference from the 12" template block used.

I'll stop here as my head was never made for intricate thought patterns.

cheers all,

Stu :D

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Nah, it would still make an ellipse. The only degrees that WONT make an ellipse are 0 and 90, with 45 being the greatest divergence, everything angle inside of that will just change the foci and effectively the 'radius' of the curve.

Oh the good old days of Trig! Calculus and becoming an engineer pretty much killed my shot at using the math I consider to be the most fun, although Calculus is close behind.

35mm radius it is!

Oz, the divergence from a circle in such a small area (especially in relation to what is being made) is going to be so miniscule that you'll laugh!

Edited by matttheguy

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Allrighty, Matt. B)

I'm looking forward to the technical data when it's ready. Just use words no bigger than 2 syllables. :D

The divergence issue does interest me greatly, as it could be a useful thing.

Stu :D

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Way cool Stu!

I'm glad I got that Safe-T-Planer. Now I just have to get a drill press.

What speed did you use to make the radius block?

Regards,

Brian.

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Very informative, thanks! What do you think the widest radius block you could make with this method is? I need about 4 1/2" for 8-string basses. Hopefully it's doable! I'll know whenever I order one of these for my drill press.

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G'day Jon. The maximum width of cut you get with the S-t Planer is 70 mm or close to 2 3/4"

If you buy or have a Stew-mac branded block, it is the same width as that. :D

It is possible to double that to get at least a 5" block, but it wouldn't be easy as you'd be running two separate tracks/passes and trying to marry both of those up to make one huge radius. It can be done though. Just takes extra time on the angle setup and fence placement. (You would have to set the angle on 2 axis/planes instead of just the one)

And Brian, It's always good to inspire someone to buy more tools quicker. :D

and by the way, the pedestal drill was cranking at -/+ 2800 rpm for all feeds.

cheers,

Stu

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G'day Jon. The maximum width of cut you get with the S-t Planer is 70 mm or close to 2 3/4"

If you buy or have a Stew-mac branded block, it is the same width as that. :D

It is possible to double that to get at least a 5" block, but it wouldn't be easy as you'd be running two separate tracks/passes and trying to marry both of those up to make one huge radius. It can be done though. Just takes extra time on the angle setup and fence placement. (You would have to set the angle on 2 axis/planes instead of just the one)

And Brian, It's always good to inspire someone to buy more tools quicker. :D

and by the way, the pedestal drill was cranking at -/+ 2800 rpm for all feeds.

cheers,

Stu

Thanks for the response! My idea was to run the 5" board against the fence, taking off 2 1/2"ish, then flip the board around and do it on the other side. Sounds a bit more tricky to do it this way, either way, thanks for the tutorial!

I do have a question relating the Wanger planer, though. A few others have said that it kicks when in use. Is there a way to prevent this? Have you experienced this? It'd be great to get 2 uses out of this attachment.

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I do have a question relating the Wanger planer, though. A few others have said that it kicks when in use. Is there a way to prevent this? Have you experienced this? It'd be great to get 2 uses out of this attachment.

Anything will bite back at you if you push it past it's safe tolerances.

It is all in the setup as well.

The instructions it came with explains the parameters for safe usage and from how I've used it I can say that it works well when used within those guidelines. Let the blades do the cutting at their rate and things will be fine and safe. I've done some thicknessing with Walnut, Blackwood and Birdseye and no problems.

The setup requires the planer not to be level or parallel with the bench but to have a miniscule amount of respite on the back edge so that the only part of the rotating planer doing the cutting is the edge closest to your feed point. If the back edge is trying to cut at the same time as the front, you'll get kick back. just as you can get with a large, flat router bit when doing freehand work. (in a router of course)

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As a foot-note to my tutorial, I figured it's one thing to make a 2 foot radiussing block..............

and another thing to actually use it and show that it works as intended.

The first photo is with the sanding jig I made for a more precise job in radiussing the fingerboard.

Note the 2 foot long block with two batten screws as primitive handles. (temporary I might add.) :D

DSC03935_edited.jpg

The next image is of the radiussed fingerboard. It's lace sheoak and a real beauty

DSC03942_edited.jpg

I finally got around to using the long block , and find it easier to get good results than a smaller block.

Now........time to do something about those darn screw/handles :D

cheers, Stu

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