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Turn your drill into a spindle sander using a homemade mandril

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Sanding the inside of a hole can be horribly aggravating, especially on a pocket hole that doesn't go the whole way through the piece. You can try using a round file, but its hard to get consistent results, and a short range of motion really slows down progress.

In my case I needed to widen every hole in a handrail by about one millimeter so the spindles could be pushed further up inside. The holes were just slightly bigger than my pinky, so doing it by hand just wasn't an option, and I didn't want to use a drill bit, which would have splintered the edges of the hole.

The solution to this was to create a mandril that could be used in a hand drill, basically turning it into a hand-held spindle sander. I made mine at http://techshop.ws
 
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Step 1: Choose an appropriate dowel to make your mandril out of

Each task is unique, so you get to tailor your tool to the task you want to use it for. I like for my mandril to be a little bigger than half the diameter of the hole I'm sanding. That makes it big enough that it won't get easily hung up in one spot and create a trough where it sanded away too much at once, but its still small enough that you can maneuver around inside the hole and give attention to where it's needed.
Robodie2 months ago

Awesome take on this; I've been doing something similar for years but am digging the slotted dowel aspect.

My version is a base layer wrapped around a nail (of whatever appropriate size), 100 grit and glued on. I have "wraps" at the ready to throw over the top of that -- the sandpaper grips the new twist, so usually extra no adhesive required.

From there, I run it through a hole block...literally a block full of holes, haha! Running it slowly backwards (depending on the direction of your twist) will tighten the whole shebang up quite nicely!

Once twisted to the correct size, reseat the sandpaper edge in your chuck, and off you go!

Attached pic shows currently used twist in the chuck, a "post traumatic twist sitting on top, and one getting shaped courtesy an old hollow anti-vibration drum stick. Oh, and a hole block in the background. :-)

They look rough, but the project didn't require precision...my apologies for the poor example!

I WILL be trying your dowel mandrel next time. Thank you kindly!

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golond (author)  Robodie2 months ago

Thanks for the kind words, and for sharing your version!

One thing I'd modify about loading the sandpaper into the dowel mandrel, instead of 'stubbing' the sandpaper into the slot, run the strip of paper a fair way bit through the slot then wrap both layers around the outside. That should help prevent the centrifugal force from pulling the sandpaper out of the slot, which is prone to happen when the paper is just stubbed down into the slot. It will make it more like a flap sander, though, so the accuracy of the sanding will be decreased somewhat. A rubber band or some glue to hold the flap down against the dowel might help with that.

Cheers!

TeleDex9 months ago

Great idea! Seems like it might help if the sandpaper extended into the chuck 1/8" or so. Gonna try that--I'll let you know if it works.

golond (author)  TeleDex9 months ago
Thanks, and please do post your results. It might be wise to wrap a heavy sheet of paper around the sandpaper that extends into the chuck to protect the chuck fingers from being abraded. Also, having a 1/8" section at the tip of the fingers that is thicker than the rest of the mandril's handle may cause the mandril to be able to spin slightly off-center, so wrapping the whole handle either in sandpaper or a paper of similar thickness might be needed to stabilize it. I'm probably way over-analyzing it, so fill us in on how it actually goes!
snoopindaweb9 months ago

In the early 70's a Buddy bought a new Yamaha 650 twin (4 cycle). It kept having valve guide problems. No Yamaha dealers around S/W Mt. could ever fix it. He got so mad He found the address of the President of the Yamaha Co and wrote Him a letter, "No computers then". The President of Yamaha sent a letter back saying "use a Tinker Toy stick and sandpaper". Yup.!

spark master9 months ago

Try putting the slit side into the drill chuck for bettererer tightness! Nice concept, I have a HUGE slow speed drill mounted to a work bench using a piece of 1/2 black iron pipe into a flange. Maybe it is like 500 rpm's. I call it my whale, and you can put a rather large piece of wood dowel in it, or a piece of EMT with a slot, you can use rubber cement to make paper stick and removal is easy.

Regardless of size, however, if you use very fine expensive paper AND slow it to 90 rpm's, you can sharpen small blades on it, or grind the edges of hand cut glass (or course in all cases you need to know about safety procedures, wear gloves and glasses, face and chest protection.

nice though

kakashibatosi9 months ago
nice idea! I'll probably just stick with my dremmel though XD

I admit a dremmel is a luxury, but this allows for much larger sizes, nice concept!

golond (author)  kakashibatosi9 months ago

Use it if you've got it. ;)

vladivastok9 months ago

GONNA GIVE IT THE OLD COLLEGE TRY. [HUMOR] NEVER WENT. WILL TRY ANYWAY. LOTS OF OTHER BUILDING EXPERIANCE.

cart5629 months ago

I totally did this to sand out the last ring I made! I didn't think to cut a slit in the dowel and just taped it, but I find it cool someone else had the same idea as me....

golond (author)  cart5629 months ago

Sounds like a good idea, especially if there isn't a saw on hand to cut a slot with. What sort of tape did you use, and how well did it hold up?

phreddy73 golond9 months ago

Glue it

silbertinfl9 months ago

I like it.

vincent75209 months ago

Nice !