New RPI 2X72

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Mocked up on Bench. Used a piece of 2" Butcher Block I had for top. Need some nuts and bolts. Have to fab a bracket for the VFD. COMING along!
 
KenH said:
You should be able to make the tool arms yourself and save a bit of money. The small wheel adapter isn't hard at all to make either. The wheels are a tad harder to make without access to a lathe.

You gonna really enjoy that grinder!
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Great point. The small wheel tool arm just needs to be square tubing. I use 1/4" wall on mine and there are zero issues.
 
Is that 1/2" or 3/4" aluminum plate that grinder is made from? I used 1/2" which is just fine, but that looks almost on the thick side for 1/2"
 
KenH said:
Is that 1/2" or 3/4" aluminum plate that grinder is made from? I used 1/2" which is just fine, but that looks almost on the thick side for 1/2"
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I believe the main plate is 3/4" I'll check it over the weekend. This machine is put together very nice. Hope it runs as good as it lools!
 
Thanks for the info on aluminum thickness - 1/2" aluminum is what I used for my grinder and it works pretty good. That is one good looking grinder for sure. If I were considering building another, I'd sure be picking some good ideas from that setup.

Ken H>
 
Can you fill us in as to why the plastic wheels are better? I prefer rubber contact wheels over aluminum, but I'm curious as to why those wheels are better than aluminum.
 
J. Hoffman said:
Can you fill us in as to why the plastic wheels are better? I prefer rubber contact wheels over aluminum, but I'm curious as to why those wheels are better than aluminum.
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Truthfully don't know why? I was looking to purchase the wheels and emailed Oregon Blade Maker and asked them what the advantage to the Glass filled wheels were besides the price (they were 1/3 less) the gentlemen from OBM answered me with "the Lightning Wheels are superior in every way to aluminium wheels" he continued and said that's all they use on their machines and on the machines they sell. I believed him because they sell both! At the point I am at with what I spent for the grinder 30-50 bucks more would not have made a difference to me. If he had told me the Aluminium were better and it was just a price thing I would have spent the extra money! But when the rep of a company tells me the less expensive item is better I listened to him!!
 
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Well, I kept waiting for some of the other more knowledgeable folks to respond about metal vs covered wheels. My experience is the solid metal wheels are just harder to grind on. Yes, the work, but just don't feel as good. I made aluminum wheels for my first grinder, but was never really happy with them. I finally went with longboard wheels (3" diameter, 2.1" wide) that are 72 hardness range. No comparison. MUCH better grinding.

I think it's the metal has no give, and any little imperfection (splice joint, etc) in the belt shows shows thru as a bump while grinding. So much so, my 1/2" small wheel is solid metal, but all the other sizes I've covered with rubber.

Ken H>
 
Ken, that makes perfect sense. Just like with hand sanding, a leather backer improves the finish immeasurably. Just adding a strip of J-weight belt is a vast improvement over sandpaper on stick alone.

I'm about to make some wheels myself. How did you apply the rubber to your wheels? I was going to make a first attempt with contact cement and an old j-weight belt. But if there's a way to get rubber to stick without sending them off to Sunray I'd love to give it a shot.
 
Ken, that is genius! Thank you for sharing those links. That will work great.

I'm also going to turn some larger ones. I guess I'll just experiment with backers of some sort glued on.
 
Well John - once you get to 2" and larger, I'd go with skateboard wheels. I've got 3", and should be able to find 2" also. They make GREAT wheels for grinding. The hardness is usually in the 70-80 duro range, and price isn't too bad.

wheels less than 2-1/2" it's hard to find them wider than 1-3/4", but that would work just allowing a tad of belt to hang over the side. Typically these type wheels are not doing LOTS of heavy grinding, just a tad of profiling in curves.

Here is a set of 62mmX51mm: http://www.ebay.com/itm/361971182736?
 
KenH said:
Well, I kept waiting for some of the other more knowledgeable folks to respond about metal vs covered wheels. My experience is the solid metal wheels are just harder to grind on. Yes, the work, but just don't feel as good. I made aluminum wheels for my first grinder, but was never really happy with them. I finally went with longboard wheels (3" diameter, 2.1" wide) that are 72 hardness range. No comparison. MUCH better grinding.

I think it's the metal has no give, and any little imperfection (splice joint, etc) in the belt shows shows thru as a bump while grinding. So much so, my 1/2" small wheel is solid metal, but all the other sizes I've covered with rubber.

Ken H>
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From the way I understand it if you grind on metal wheels eventually will experience a belt blow out and from what I was told it can be quite dangerous.
 
KenH said:
Well John - once you get to 2" and larger, I'd go with skateboard wheels. I've got 3", and should be able to find 2" also. They make GREAT wheels for grinding. The hardness is usually in the 70-80 duro range, and price isn't too bad.

wheels less than 2-1/2" it's hard to find them wider than 1-3/4", but that would work just allowing a tad of belt to hang over the side. Typically these type wheels are not doing LOTS of heavy grinding, just a tad of profiling in curves.

Here is a set of 62mmX51mm: http://www.ebay.com/itm/361971182736?
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These are exactly what I want!
 
IMG_20170829_51165.jpg Ok gents I got my Grinder running!! Still have to build bracket for VFD and rewire it for the HYPER-DRIVE! But I had to try it!! 36grit Ceramic Hermes belt profiled this blade for my Brothers Christmas gift in 2 minutes!! Without exaggeration!! Can't wait to try a bevel!! This thing runs GREAT!! Had a little problem with tracking but figured it out!!
 
You are going to be so happy with a 2X72 grinder. I did the full gauntlet if grinders starting with a 1X30", then a 6X48", then finally I built a 2X72 and there is just no comparison! Now for all the accessories, small wheel, etc.
 
I should have mentioned about when I said I'd ran the full gauntlet of grinders, that my first 2X72" was with 3 step pulleys and belts. I thought that was all that was needed, until I finally broke down and built a 2X72 with VFD. What a difference! Actually the cost of pulley's 'n belt vs VFD setup isn't all that much difference for a hobby setup. The 1ph vs 3 ph motors are about the same, and the cost of a Chinese VFD is about the same as buying the bearings, belt, and 3 step pulleys. and WOW!!! What a difference.

"IF" you prefer to buy the NEMA 4X VFD, that's only about $200 over the Chinese NEMA 1 unit, so that's not all that much extra over pulley 'n belt setup. This is "ass-u-ming" you're having to buy everything, pulleys, shaft, bearings, motor, etc.

Ken H>
 
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