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Mounting Guide: Kutzall Sanding Discs & Dish Wheels

Many of you have been wondering why we changed our Dish Wheels over from 5/8" bore to 7/8". This was to ensure proper mounting procedures were followed. To help, we've developed a Mounting Guide for your reference.


Kutzall Sanding Discs and Dish Wheels feature a 7/8" I.D. and are intended to mount on a standard electric angle grinder with a 5/8" shaft. They mount on the 7/8" shoulder found on the shouldered bushing or adapter included with most angle grinders. If for some reason your angle grinder does not have one of these bushings, you may obtain one by contacting your grinder manufacturer. Mounting Kutzall wheels using a shouldered bushing assures that the wheel will spin as straight and round as possible. This makes working with the tool smoother and more comfortable, while assuring that you use the entire surface of the wheel equally. The shouldered bushing is put on the grinder first, followed by the wheel and then the nut.

 

Tip: Shouldered bushings may be found on the parts list for your grinder on the manufacturer's website.

 

Angle Grinder Mounting Guide


8 Responses

Kutzall
Kutzall

October 05, 2016

Your newer grinder might have a 5/8-11 threaded shaft, if it is a USA-specification model. If it is a European model, we would expect it to have a an M14 shaft. In either case, of course, the grinder likely came with nuts and/or a bushing having a 7/8” or 22 mm shoulder, for 7/8” or 22 mm I.D. accessories. Older grinders often had a smaller 3/8-24 shaft, with a shoulder nut or bushing for a 5/8” accessory I.D. When the newer grinders in the USA first came on the market with 5/8-11 shafts, many Kutzall users put our 5/8” I.D. wheels directly on the 5/8” shaft. However, because the thin steel wheel usually positioned on the shaft right over the thread, it did not align itself concentrically to the shaft. The wheels then had a lot of “hop” (radial eccentricity), and did not perform as well as they could. We subsequently changed all of the Kutzall wheels to the modern 7/8” I.D. size.

Now, if you had an older grinder with the 3/8-24 shaft size, and wanted to fit the newer 7/8” I.D. Kutzall wheels, 3M and others make adapters to mount the newer 7/8” I.D. accessories on to that small shaft size. However, you need to go the other way with your old wheel. We know of only two ways to make the 5/8” I.D. wheels work on the newer grinders. The easiest would be to just mount it over the 5/8” shaft without a stepped bushing or nut to ride on. As mentioned above, though, that usually leads to a wobbly situation, although some users work a bit to get the wheel centered when tightening the nut, and do OK with the wheel that way, after a sufficient amount of repositioning. The other option would be to find a friend or co-worker who has a lathe or milling machine, and enlarge the I.D. to 7/8”. I wish there was an easier way we could suggest, but it’s not easy to go from the 5/8” bore size to a proper fitment on a 5/8-11 or 14 mm shaft.

Klaus
Klaus

September 23, 2016

Hi..
I bought an 5/8 bore carving wheel years ago and somehow forgot about it.. i used always the coarser one (red) that seems to have an 7/8 bore, that fits perfect on my makita grinder. Now I was happy to find my 1152x fine wheel with that 5/8 bore and cannot fit it onto my grinder. Is there some washer that can help fitting the wheel on my grinder ? I tried other grinders i have available in my shop but none seems to fit.
Thanks for any tips !
Best regards from Germany
Klaus

Kutzall
Kutzall

September 15, 2015

Chuck,

We are very sorry that you had to open up the I.D. on your Kutzall disc. Because the Kutzall discs are rather heavy, we are extremely cautious about not making the I.D. size larger than absolutely necessary. At the 10,000 to 12,000 RPM typically generated by electric angle grinders, any sloppiness in the I.D.-to-shaft fitment results in run-out, which can translate to a lot of unpleasant vibration for the operator and a deterioration in finish quality on the work-piece. Because we make the discs knowing they will be used on a wide variety of grinders, from many manufactures, all with significantly different tolerances for their shoulder nut or flange shoulder dimension, we aim our tolerances for the low end on I.D. size. Again, we apologize for the inconvenience to you. We realize it’s a bit of a pain when someone like you has to fit the wheel up, but you probably have the lowest-possible-vibration setup going as a result. Sometimes nothing beats a hand-fitment!

Kutzall
Kutzall

September 15, 2015

Alias,

The parts listing for the Makita 4030 model calls for the inner flange #35. We do not have this model of Makita grinder here, but an examination of this flange in replacement part listings appears to show a projecting accessory shoulder considerably smaller than 7/8", which is the size required to fit the 7/8" I.D. on a Kutzall disc. Some grinders intended for smaller guards and smaller accessories used 10 mm x 1.25 thread or 3/8-24 thread shafts, and a 5/8" accessory shoulder diameter on the nuts or flanges, which is probably what you have. We are aware of conversion adapters available online which claim to allow for adapting 7/8" accessories such as Kutzall discs to the 3/8-24 shaft size, but we have not specifically seen such adapters for a 10 mm x 1.25 shaft.

Kutzall
Kutzall

September 15, 2015

With some grinders, both nuts (where both a top and bottom nut were supplied), or the nut and the backing plate (where just one nut and a bottom backing plate are supplied), both have a 7/8" diameter projecting shoulder. When the two shoulders both enter the 7/8" bore hole of the Kutzall disc (both facing each other), the total dimension of the two shoulders added together is greater than the thickness of the Kutzall disc! In this case, with the nut fully tight, the Kutzall disc can still spin freely on the shaft. When this problems occurs, it is usually possible to turn the top nut over, so that it presents a flat face with no projecting shoulder. We are not certain this is what happened on your grinder, because having the disc spin freely between the nuts or nut and washer makes the wheel non-functional, and could damage the wheel or the nuts, but it still would not make it come completely off the grinder. You are correct that many ceramic metal-grinding discs (for snag-grinding welds, etc.) are much thicker than the Kutzall disc, which is made of steel. With the ceramic discs, the dimensions of the two shoulders added together when facing each other is still less than the thickness of the ceramic disc, and so the disc can be tightened correctly. If we made the Kutzall disc from steel as thick as many ceramic discs, it would be much too heavy for the typical angle grinder. If this is the problem, please see if your top nut is flat (no 7/8" shoulder) on the opposite side, and face this toward the disc and grinder body.

Chuck Hornbeck
Chuck Hornbeck

August 03, 2015

I had to scrap paint from the disk and slightly file the inner of the hole to get a good fit against the 7/8 rimmed piece. You might want to mention that possibility to future buyers.

Glenn h
Glenn h

June 25, 2015

I would like to make a comment RE mounting your disc. I Did just what you show, but what happen is when I shop the grinder the disc spun off, no matter how tight I try to get the nut,
The thing is the grinding disc never do this, my thought is something to do with thickness of the grinding disc. But not sure, So my thought was to make a fiber washer that will compress when tighten, that worked, disc does come off.

Just my thoughts on this. Really like the disc. I used to grind a bevel on rubber floor mats.

Alias
Alias

June 11, 2015

Hello,
Can I mount it onto a grinder with 5/8-in bore size with M10 (10mm) spindle size, specifically Makita 4-inch angle grinder GA4030?
Thanks.

- Alias

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