I recently bought two 8" CBN wheels from Ken Rizza. They're the "4 in 1" type, as he calls them, meaning that the abrasive surface wraps around the side of the wheel for 3/4 of an inch or so. Consequently, the wheel is about 1 & 1/4 inch wide. I'd like to put them on the new Rikon 8" slow-speed grinder (model 80-808) but I don't know if the guards are far enough apart to accommodate a wheel this wide. Yeah, I know I don't really need the guards since the CBN wheels can't blow up like a stone wheel can, but I'd like to contain the "dust" somewhat and having the guards on will help.
I have the smaller HP 80-805 Rikon slow speed grinder. Looking at the 80-808 it seems to have the same guard design, which is for the 1in wide ceramic wheels.
I would like to get the same CBN wheel as you have purchased and concluded that if I did, I would need to remove the outer side of the guards.
My 1 hp Rikon came in yesterday, and I will pick it up shortly so I can mount it on plywood, mount my CBN wheels, and then take it to our club meeting tonight. The metal dust created by the CBN wheels is very fine, and will float around a lot. Some try to contain the dust with magnets. Well, if the wheel is totally enclosed, you will get most of it. If we really want to be proper about it, some type of dust collection should be attached. If you read the CBN wheel article I posted a while back, I found metal dust on a magnet that was inside an closed cardboard box about 2 feet above my grinder (on my web site, or in More Woodturning magazine). Having minimal hooding and dust collection should get 99% of it.
Thanks for the tip. When you get your grinder together, I'd appreciate it if you could measure to see what the maximum possible wheel thickness is. Thanks.
Get some longer screws and make your self a spacer to move the guard out. Possible just a larger nut might be enough space. When I have a problem like that i usually have a length of hollow pipe or copper tubing that I can cut and use as a spacer
I have the 80-808 grinder also but have Ken's radius wheels that are 1.5" wide. For me, can't do what your looking to do without modification. Your inside cover will fit fine and you might luck out (since your only 1.25" wide) but I doubt it. Probably need a spacer in-between the cover but then your threaded stud posts might not be long enough to begin getting the knob on. Doable but not without aggravation. However, at least on mine, if you plan on using a Wolverine type jig, the debris shoot will not rotate enough to line the holes up to attach the inside cover to the motor body. Hits the top of the wolverine platform. If you slot the existing holes in the cover maybe a good 1/4" you can get its orientation correct.
Any way a 8" PVC sewer pipe cap can be modified to work as the outer half of the "shield" (dust collector)? I am immediately concerned about static charge and effectively collecting the dust, so just thinking "out loud" (on the keyboard) here...
In the wood heating world, there are a number of steel thin-wall pipe options and I'll bet an appropriate sized end cap could be found to replace the outer part of the stock shield if it proves too narrow to accommodate the CBN wheels. I'm hoping to do a similar upgrade with my 8" Delta grinder, so I'd like to read how you make out on this.
First to Dick's comment, there is very fine metal dust that floats in the air like wood dust will. Magnets alone will not catch it all. If you have the wheel totally enclosed, and have HEAVY magnets around the open space, then yes, you will probably get almost all of it.
So, got the grinder home. First thing I did was to turn it on with the grinding wheels that came with it. Scary compared to what I am used to with CBN wheels, +/- 1/16 run out, or 1/8 inch total. Like the blades that come with your bandsaw when you get a new one, get rid of them. Next I took off the rubber feet. It was wobbling on my bench, so I moved it to my table saw, old Delta Unisaw, and with 3 feet on the saw top, the 4th was up in the air 1/8 inch. I don't like the rubber feet as I want it more solid. Probably not much of an issue if you keep the feet on, but still.... So, took it to my belt sander and fixed that. I removed the outer wheel cover, and put on some D Way 1 1/2 inch wheels. I needed to shim them out from the grinder seating with 3 washers, each about 1/8 inch thick. There are flanges on the inside of the housing for the tool rests that come on the grinder. I will probably grind them off eventually, and would be able to remove at least one washer, and maybe 2. There is some run out with the CBN wheels at start up, but when I used big box store washers on my Baldor, I got the same reaction. They run smooth when at speed. It takes it about 3 seconds to reach full speed with 2 CBN wheels on. This is good. Next, I had to mount the Wolverine bases under the wheels. They went up on 3/4 inch thick plywood to get them so that my robo rest will set at center height. With my old blue no name grinder from Woodcraft, the grinder had to go up on a piece of 3/4 plywood. There is a small dust collection shoot under the wheel housing. I had to remove them to be able to fit the Wolverine base under the grinder. After mounting the Wolverine on some plywood, I went to position it on the left side. My robo rest would not go all the way up to the proper position at the wheel, and there was a gap of about 1/4 inch instead of the 1/8 inch which is preferred. The housing vertical piece is bent around the round surround piece, and I ground that bend off flush, which made it a perfect 1/8 inch space, which I thought was cool. So, I go over to the right side, and tried the same thing, and the gap was about 3/8 inch plus, so not really accurate. I will grind it off/fix it later. I also took off the little lamp they put on the back side. Yes, it will work, but not nearly as good as I want. Not bright enough, and it won't bend around far enough to put good light where I need it. Reminds me of the lamp on my Jet mini lathe.
So, conclusion, it isn't a Baldor, or even very close. For the price, it still is a pretty good deal. All that remains now is to a year or three of sharpening on it.
Opinions here are my first impressions, and could change with use and abuse of this tool, and I will abuse it just to see how much it can take.
But the 40 mm wide CBN wheel fit on my Baldor with a 3 mm thick gasket between the inner and outer cover. Cut from an IKEA plastic placemat.
Also needed to remove the inner washer and use 20 mm thick washer, machined from aluminum between the CBN and the nut to have enough thread to tighten the nut.
Thinking while typing also but I would think with a magnet and a decent dust collector that you wouldn't need a hood. I don't normally see sparks so I don't think it would be a fire hazard. Any thoughts on possible hazard? I can't say for sure there is any fine dust in the air from the wheels but I see plenty of metal particles at the base of the grinder, even without magnets.
Sparks are very minimal, but I would not have a hose right at the base of the wheel. One turner hung a magnet 1 foot above his grinder, and he had no hood around the wheels, having removed the entire wheel shroud. The magnet got a lot of dust on it. If your hose is in a box and back a bit, I would say fire risk is non existent. Maybe a sanding hood like I use when sanding bowls. I was really surprised at how the metal dust would float and fly.
I built a wooden plenum behind the grinder, ventet to a dedicated vacuum cleaner with a metal can. Both the grinder and the cleaner start from the same switched outlet. There is very little in the can of the cleaner, so the only draw-back is the noisy vacuum.
Thanks for all the helpful comments, guys. I've decided to pass on the Rikon; I have a 7" Baldor (the CBN wheels are on it now, with the guards removed) and I'm just gonna make a set of guards for this setup. I'll post pictures when it's done.
On a related note, vis a vis using a dust collector or shop vac: I think maybe there's a risk of the metal dust (conductive) getting into the motor windings -? Seems like I read that somewhere. In a Shop Vac, at least, the air flow from the hose is used to directly cool the motor, so maybe this is potentially a danger.
Jorge, this is a link to an article that I posted on the forums a while back. I use the D Way wheels, in part because I consider Dave Schweitzer a friend as well as a nice guy to deal with. Ken Rizza of Woodturning Wonders is some thing of a new comer in this area. I have chatted with him a number of times, but already had more CBN wheels than I can wear out. His look good and I have never heard any complaints about them. I am pretty sure I have them pictured in my sharpening clips on You Tube.
Yes, probably most if not all "shop-vacs" use some of the air to cool the motor. The air does go through whatever filter is in place so the question is whether the filter is fine enough to catch undesirable particles.
I know of 2 people who destroyed the motor (bearings) in their vacuums by cleaning the sand out of their cars with no filter bag (was set up for wet use) and the other with a filter bag that was not properly installed.
