Surface Grind 101

I have off today so I have some time in the garage. Just a example of grit and finish. Here’s some pics of a v block I’ve been doing. 46grit aluminum oxide. Don’t know if it’s right but that’s what I picked. First pic is manufacturer finish second and third are my finish.
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All three taken with zoom on iPhone. Kind of hard to get the look but my finish has more of a reflective,polished look. Fingerprints make it look bad. Kind of funny looking at the pictures how grainy they all look but yet you don’t see that unless magnified. Smooth as glass.

Very nice finish. I'll take the 2nd and 3rd over the commercial finish.
I was watching a machine dealer on Youtube. He showed the finish after he ground a small block. It had a scalloped finish.
NOT GOOD!=Do not buy this machine was the message I got out of it anyway.
 
Looks great Bob!
How do you center the adapters on the wheels?
Isn't there 1/8" adjustment?
The correct 1 1/4" grinding wheels usually fit the 1 1/4" adapters just fine, a nice sliding fit. Cheap wheels and abused used wheels, not so much. Still, very little runout. But enough to make the wheel out of balance and out of round. Dressing it makes it round. Balancing makes it balanced, if you want to go down that rabbit hole. You can also put a paper or brass shim around the hole for any excessive runout. A lot of surface grinder hands swear by balancing wheels, but they probably do not work in commercial shops, because it takes a fair amount of time to do. $pecial equipment is also needed for balancing, though it can be shop made. Balancing seems to get more important as the wheel diameter and/or speed increases.
 
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A quick word on first grinding wheels and learning grinding in general.

To learn how to grind and learn the characteristics of a grinder I would start with a 32 grit Aluminum Oxide Vitreous bond wheel in a hardness of I or J. Your arbour sizes and diameter should fit your grinder. It is easier to learn on a 1/2" wheel because it puts less pressure on the work than a 3/4" wheel, etc.

Dress your wheel often. Know that soft materials, including soft steel, will strip the grit from the wheel, and load the wheel easier than very hard tool steel, so the wear in much faster on soft steel. Use that wheel up! Then, after you have a lot of experience on 32 grit, try a 46 grit wheel and see how things change. Every grinder hand I know has a different preferred grit/composition they prefer. Most recommend I or J hardness though - I don't understand why, exactly but that seems to be a universal bit of advice.

At some point you will need a second arbour for a diamond wheel. Pretty soon after you get really going on projets, you will eventually need to grind carbide: a drill, insert or scraper blade. This takes a very different set of techniques and is well worth learning, but you will experience different challenges and successes grinding carbide bits...

Buy or make a good dressing block with a medium or larger diamond. Dressing your wheels can be done with a small diamond, but it is easier to do with a little larger one, 1/4 carat or 1/2 carat will work well.

Best of all just grind with one type until you can predict the result in a variety of materials: regrinding hardened parallels, etc.

Lastly, mount a wheel on your arbour, and balance it, then leave it until you retire it! you can use up a wheel very quickly if you do a lot of shuffling around... I figure it is just lost learning opportunity. I have 3 arbours at present, with only 2 of them occupied. I have 4 spare wheels, all in hardness J.
 
My current go-to wheel is a Radiac ruby wheel with both ruby colored and pink granules, put together with a very open structure. It is a
WRA46H V8. It runs cool and stays open. It is well balanced. It seems to work great on everything, including the mag chuck, perhaps the most difficult job there is, and it is also the job that influences every other job you do.
 
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