Flap Sander: Mac Mop motor and arbor?

[John Poole]

I'd like to have several Mac Mops (see an example of one at Klingspor's site: http://www.woodworkingshop.com/cgi-b...adItem=MM00518 ). Specifically, the manufacturer Klingspor states:

They are best used on a motor with at least a 3/4" diameter spindle and operate at between 1100 rpm and 3000 rpm.

I'm looking around at buffers and motors on stands that might have variable speeds and am not finding much. It looks like motor speeds are pretty much fixed, 1725 and 3450, and that variability is an expensive option. It would be interesting to be able to try various speed between 1100 and 3000. I'm looking for a motor that has 3/4" spindles on both side, akin to a buffer, sitting upon a stand (like the Grizzley buffer/grinder stand at http://www.grizzly.com/products/Stan...-Grinder/H7834) would be the solution. The issue I've yet to investigate is a motor and pulley (several pulley choices) aspect.

Has anyone specified and assembled a flap sander unit that would be just like a buffer, but with a slower motor within the manufacturer's RPM limits using Mac Mops?

I especially like the idea of the mop being out in the open as a buffer stand affords so you can hold a piece against the spinning mop from all sorts of angles.

I think I had a Mac Mop back in the early 90s running on a Shop Smith at it accomplished the task of easing edges marvelously.

[John Poole]

Looks like the formula for determining the RPM of the driven shaft is:

(Speed of drive pulley X Diameter of drive pulley )/Diameter of driven pulley

Example with initial RPM at 1,750:
speeding up the RPMS: (1,750 x 7.25)/2.75 = 4,613
slowing down: (1,750 x 2.75)/7.25 = 664

So, the solution seems to be selecting a pulley combination given a standard motor speed, e.g. 1,725.

[Mark Levitski]

John,

First, I think that you would like the Mac Mop but they do not last very long for the money. We tried one and then went for a Sand-Rite flap sander which has a load of slashed abrasive in it that you can feed out as needed. Way better investment.

We use a 1725RPM buffing machine (the Jet). Not variable speed, but works well. We also have a 1100RPM Caswell buffer, but have not tried the flap sander on it--the shaft is a bit different and the Sand-Rite fits right on the Jet. The long shafts are really nice for sanding or buffing. We have Grizzly stands and they are great.

Caswell site has a lot of info re: RPM vs. diameter for buffing.

[John Poole]

Thanks.

It appears the buffing machine is no longer offered by Jet. A search for "buffing" at their site only returns a grinder; moreover, I recall seeing a post in this forum where someone mourned the nonavailability of the Jet buffer.

Here's what I found for Caswell: http://www.caswellplating.com/buffs/34hpbuffkit.html

Grizzly: I'm inquiring about what the length of the shaft is that is threaded -- this will determine what widths may be accomodated.

Sandrite: Here's what I found for Sandrite: http://www.sand-rite.com/db-612-dlx.html

[Perry Holbrook]

I have a Sand Rite head mounted on a direct current motor with speed control. (Parts came from and industrial "spool" sander at auction). I usually run 120 or 150 paper on it and run it at 800 to 1100 rpm. The industrial flap sanders recommend 600 to 800 rpm for their machines.

I have a double end arbor with 2 Mac Mops installed, 120 and 150. Klingspor used to sell the arbor as a kit, they probably still do. You need to size the pulleys for no more than 1500 rpm. The faster you spin the faster you wear out the paper and the more you are polishing and not sanding.

Hope this helps.

Perry

[glenn bradley]

The Shop Fox arbor set that Klingspor and others sell has a stepped pulley. That along with proper stepped pulley/motor might do what you're after. Just another idea.

[Charles McKinley]

Probably the cheapest option is a VFD (Variable Frequency Drive), a used 3phase motor and the arbor kit. Used 3ph motors used to be about $10 per hp but I'm sure that is long gone due to the price of scrap metal.

[Callan Campbell]

John, I have the Caswell buffer in question. I don't have anything mounted to the shafts at the moment, so if you need specs or a picture or two, let me know. It's the slower 1100RPM model. I got rid of a cheap and FAST Grizzly buffer with the 3450 RPM motor and replaced it with the Caswell. The wailing about the Jet buffers was probably me, as I discovered that they'd quietly been killed in production while still being listed on Jet's website forever as still available. I looked over the buffers for years, not realizing that I needed to pull the trigger and get one since they were on their way out. Maybe Jet will return with some type of model once business in general gets better for everyone and sales climb back up.

[Noah Katz]

That Shop Fox arbor looks pretty nice.

I looked at the parts list and it has ball bearings.

You could make it really versatile with a cheap used 3-ph motor and a ~$100 VFD like one on this page

http://dealerselectric.com/mfg-subca...cID=164&mID=-1

[John Poole]

Thanks.
...

Grizzly: I'm inquiring about what the length of the shaft is that is threaded -- this will determine what widths may be accommodated.

I spoke with the technical representative for Woodstock ShopFox International (not sure if they are affiliated with Grizzly, but my inquiry to Grizzly ended up with ShopFox) who advises that the threaded section is 4" on each end. He did not know if the shaft had been case hardened, as I inquired if it would be possible to extend the thread with a die for another 1/2".

[John Poole]

I'm building a specification for a do-it-yourself assembly. I've shared this spreadsheet (price, links, photos) of the components at:

https://spreadsheets.google.com/ccc?...oS0lVd2c&hl=en

If anyone has edits to suggest, you can post a reply to this thread of the topic; to assure I am aware of your message, please send me quick message "flap sander spec". For some reason, I'm not getting notification of updates to this topic and I'll check my settings &etc. In the meantime, direct contact to me is the best way to assure I receive you message.

[Noah Katz]

I spoke with the technical representative for Woodstock ShopFox International (not sure if they are affiliated with Grizzly, but my inquiry to Grizzly ended up with ShopFox) who advises that the threaded section is 4" on each end. He did not know if the shaft had been case hardened, as I inquired if it would be possible to extend the thread with a die for another 1/2".

I guess the interest in thread length relates to being able to tighten down on narrower buffs.

You could just use a spacer sleeve made from PVC pipe or somesuch, which would also save having to run the nut that far.

[Alan Marchbanks]

I mount the flap sanders on an arbor and use a morse taper chuck on my lathe which has variable speed. Works very well for me.

Alan