3 phase setup for sanding bowls.

[Bob Bergstrom]

In a previous thread a Creeker asked about angle drills for sanding. I suggested using a 3 phase motor, a controller and flex shaft. A friend of mine has been sanding with one for a couple years. Here’s some pictures of his setup. He has a chuck on the end but I would use a quick connect for driver bits. Much smaller and less likely to scare a bowl or the user’s arm.
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[John K Jordan]

In a previous thread a Creeker asked about angle drills for sanding. I suggested using a 3 phase motor, a controller and flex shaft. A friend of mine has been sanding with one for a couple years. Here’s some pictures of his setup. He has a chuck on the end but I would use a quick connect for driver bits. Much smaller and less likely to scare a bowl or the user’s arm.
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Do you know more about the sanding "ball", is it something available to buy or purpose made, sandpaper cut from a standard disk then secured by some means? Almost looks like a disk of wood. Some flexible backing inside?

Great idea, that should have a lot of uses.

[Bob Bergstrom]

Do you know more about the sanding "ball", is it something available to buy or purpose made, sandpaper cut from a standard disk then secured by some means? Almost looks like a disk of wood. Some flexible backing inside?

Great idea, that should have a lot of uses.

John the inflatable mandrel is part of the sanding kit at Klingspoor. Here a url.

http://www.woodworkingshop.com/product/kx11360/

[Don Frank]

I am curious. Is there any advantage over a Foredom flexible shaft style using the same sanding ball. I own a couple of Foredoms but I have never considered using them for sanding bowl interiors.

[Bob Bergstrom]

I am curious. Is there any advantage over a Foredom flexible shaft style using the same sanding ball. I own a couple of Foredoms but I have never considered using them for sanding bowl interiors.

Don, I personally would not use a ball sander on a bowl. This gentleman has years of experience sanding bowls that were cut using a scollsaw. He would cut ovals on a bevel. The glue them in a stack. He also has a number of other inflatables to use if needed. All my sanding is done with a disk. He used a Guinevere sanding unit. He could only sand 20 minutes and had to let the motor cool. This unit will sand all day nonstop. It has a 1/2 hp motor.

[Reed Gray]

Where did he get the flex shaft??? I am looking, and thinking for starters, I could drive it off of my 1 hp mini lathe.

As for the Foredom set up, they tell you it can run a 3 inch disc. While I would think it can, I also think that is over stressing the set up. With the 3 phase set up up above, you could run 3 to 6 inch discs.

robo hippy

[Mike Nathal]

Those ball shaped sleeves go for more than $3 per sleeve. They better last a long time to be cost competitive. But I see no reason why standard 2" or 3" disks wouldn't work with the same set-up. Also David Reed Smith has an article on making your own sanding balls.
http://www.davidreedsmith.com/articles/foamballsander/foamballsander.htm

[David Gilbert]

Reed, from the photo of the top of the flex shaft it looks like this is probably the flex shaft from Garrett Wade. It costs about $40. I think the Foredoms are about twice that.

I'd love to have his setup but guess that it's pretty pricey.

Cheers,
David

[Bob Bergstrom]

Look on line and they're a number of flex shafts available all the way up to industrial grade bidirectional ones. I would think one from any of the tool suplliers would work I see some are 3/8" shafts. I would like the ones with the smaller chuck on them.

[Olaf Vogel]

Reed, from the photo of the top of the flex shaft it looks like this is probably the flex shaft from Garrett Wade. It costs about $40. I think the Foredoms are about twice that.

I'd love to have his setup but guess that it's pretty pricey.

Cheers,
David

http://www.garrettwade.com/flex-shaft-with-chuck.html
These are ok, if the spin is in the right direction. Decent size, decent price.

Coupled with this
http://www.garrettwade.com/multi-angle-attachment.html?green=36DCD805-34CB-5523-92D3-AC3C94D7C0AA

to get the angle, if you are using a flat disc. You want a handle to control the direction.

or one of these
https://www.amazon.com/Milwaukee-49-22-8510-Right-Angle-Attachment/dp/B000BYEJ02
to get into smaller spaces

[Marvin Hasenak]

If I wanted a rig like that I would look at industrial sewing machine servo mtartotors. Single phase and they have a built in controller for setting the speed. The cost starts at about $100, if you go this route, skip the electronoic version of speed control, go for the knob.

[Harold Balzonia]

How does one connect the flex shaft to the shaft of the motor? Is there some kind of collet I can't see? I have a couple extra motors sitting around.... now my wheels are turning but I don't know anything about flex shafts.... how do they connect to the motor?

[Bob Bergstrom]

Most use a connector with two set screws our a Jacobs chuck with a set screw.

[Olaf Vogel]

How does one connect the flex shaft to the shaft of the motor? Is there some kind of collet I can't see? I have a couple extra motors sitting around.... now my wheels are turning but I don't know anything about flex shafts.... how do they connect to the motor?


Shaft couplers or U-joints
ex. https://www.princessauto.com/en/detail/3-8-in-high-torque-u-joint/A-p8649345e

Flex shaft ends are usually square. so drill and tap end of the coupler, put a set screw or two to hold the shaft.

[Malcolm McLeod]

I have no idea of the 'duty cycle' your friend applies to this rig, which looks "epic cool" (humor me; trying to be more 'millennial' for my sons :cool:), but I'd recommend he re-orient the VFD so the faceplate is vertical. It allows proper convective air flow over the VFD's heat sinks.

[Reed Gray]

Well, this is getting interesting... I would need about an 8 foot flex shaft with reversing capabilities, a 1 hp motor with reverse, a motor mount, a chuck for the mandrills, and some sort of handle mechanism so I could hold the discs... Then mount it on an articulated arm with 3 axis movability/rotation capabilities...... The picture is getting clearer...

robo hippy

[Olaf Vogel]

Hi Reed

I haven't been out in the shop much because of...
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At -20C and snowing sideways, I'm huddled on the couch, by the fireplace with a book, mulled wine, my wife and baby. :)

Since this discussion has gone on for a while, I ran out and snapped some pics.

This is my MultiFlex, made in England, likely 50 years ago. Basically an oversized Foredom. its a good all-in-one solution and offers various different rpms.

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The Flexshaft is only about 3', so its mounted on a board, that I can hang on the wall and move as needed.

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The business end is a standard 1/4" compression fitting that will accept a lot of different attachments, including hex.

I looked for a while and found a few other flex shafts. Much more heavy duty and longer. Very flexible. About 3/4" OD, 6' long, weighs about 5 lbs.
You can see the coupling on the right. The other is a standard 1/4" thread that fits Home Depot style discs.
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As you likely guessed, these run only in one direction. Inside the sheath the shaft is twisted, to transmit torque. Run it backwards and the whole thing ties itself in knots. Put too much torque backwards and the shaft expands inside and stalls.

This is my faourite. Also 6' long, more flexible, lighter. Its small chuck on the user end, with the adjustable handles.
Coupling on the other.
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These later two get attached to a 3 phase buffer I have, and the VFD for speed control.
If I want a 90d bend, then I use the Milwaukee attachment mentioned previously.

[Bob Bergstrom]

Well, this is getting interesting... I would need about an 8 foot flex shaft with reversing capabilities, a 1 hp motor with reverse, a motor mount, a chuck for the mandrills, and some sort of handle mechanism so I could hold the discs... Then mount it on an articulated arm with 3 axis movability/rotation capabilities...... The picture is getting clearer

robo hippy



Reed, might as well throw in a trigger control or like the dentist used to have with foot paddles. I agree that some type of 3 dimensional apparatus would be an asset. I used this system and it worked best with just a handle on the end of the shaft. It was quite manageable inside open bowls. I tried a Dewalt right angle drill attachment and the cable can get in the way. The closer you hand is to the mandrel the easier it was to control the rotation. I really preferred a quick connect to a geared chuck. Too many sharp edges and it extended the sanding disk farther from my hand. I have a friend with a close quarter Milwaukee drill/driver which is longer than the regular geared chuck drill, and found it harder to control. I would think connecting two shorter cables might work for an 8 footer.