Precision stones ...

[FOMOGO]

At the point in my Acra mill rehab where I will bee wanting to address any burrs or high spots on critical surfaces. My question is are precision stones really necessary, and if so where can I acquire them at a reasonable price. Thanks, Mike

 

[WobblyHand]

Are they necessary? Maybe not, but they do make things a lot easier. I bought some smaller ones (2x4) from jlrkmr2006 on eBay. They do work, and only take down the high spots and burrs. I used them on my mill and my lathe to knock down any inadvertent dings I caused. Pretty pleased with them.

 

[benmychree]

An India stone is also appropriate, I have used one for removing scraping burrs for many years, my thinking is that the so called "precision stones" are more faddish than necessary for anything that most of us do.

 

[davidpbest]

I bought my pair from Lance Baltzey and use them every day to ensure there are no burrs, dings, or high spots on the vise, XY table, and parallels. He offers a few sizes and you can find them at the following link. You do need a matched pair so they can be properly cleaned.

HOME | 26AcreMaker

www.26acremaker.com

For those who do not know about precision ground stones or their use, this is a good reference:

www.youtube.com/watch?v=DVLXsq7pi9Y&feature=youtu.be

If you'd like to see Lance and his shop, here is a good video on that topic:

www.youtube.com/watch?v=_fu3orrQkfo&feature=youtu.be

I ended up making a custom case to protect my stones as documented here:

Custom Case for Precision Stones

Precision Ground Toolroom Stones from Lance Baltzley of 26 Acre Maker. Click image for descriptions.

flic.kr

 

[ErichKeane]

I made some on my surface grinder for myself and some friends in an afternoon (4 sets?) that I use all the time, they are fantastic and better than just a normal stone. I'm sure Lance's are better than mine, but our sets all work fantastic and were reasonably cheap. Though, it requires a surface grinder

 

[aliva]

I'd like to have some but at the price from Lance $250-280 beyond my budget. That's why he can afford to buy all those machines.

 

[ErichKeane]

I'd like to have some but at the price from Lance $250-280 beyond my budget. That's why he can afford to buy all those machines.

Yeah, his are pretty costly :/ They are reasonably easy to make with a surface grinder and a diamond wheel, I was able to make 4 or 5 sets for ~$150 (stones + diamond wheel). Its a bit messy and grimey work, but at least they last a long time so I dont have to do it again

 

[WobblyHand]

I'd like to have some but at the price from Lance $250-280 beyond my budget. That's why he can afford to buy all those machines.

Those are out of my budget too.
You can get a more modest two surface ground stones for $90 USD from https://www.ebay.com/itm/304643323335?hash=item46ee2835c7:g:arUAAOSwpvhjNGEw
If you need more surfaces ground, that will cost more. I bought the two surface stones a couple of years ago.

 

[ErichKeane]

Those are out of my budget too.
You can get a more modest two surface ground stones for $90 USD from https://www.ebay.com/itm/304643323335?hash=item46ee2835c7:g:arUAAOSwpvhjNGEw
If you need more surfaces ground, that will cost more. I bought the two surface stones a couple of years ago.

FWIW, when I did mine, I did 4 sides, but have never used anything but the 2 large sides. They are good for most use cases IMO.

 

[Jake M]

At the point in my Acra mill rehab where I will bee wanting to address any burrs or high spots on critical surfaces. My question is are precision stones really necessary, and if so where can I acquire them at a reasonable price. Thanks, Mike

Are they "necessary"? Probably not. They do have a limited scope of usefulness. They will take down VERY minor inconsistancies, but they're not for much that you can feel when running your fingers across. I have to say though, that within that limited scope of usefulness, they're just about magic.

A spectacular additon to these is a carefully made "Dead File", as introduced to me by homebrewed. The same idea kind of, it's a hand file piece with the teeth lapped flat, so just like the stones, they can't dig in to a flat surface, but they're capable of removing larger amounts of metal.

https://www.hobby-machinist.com/threads/precision-ground-flat-stones.101760/post-976980

I think the only way that ground stones will come cheap is if you make them yourself. I was lucky enough to be able to borrow a set the first time I ever needed them, and when the need arises again, I will buy a set and call it an expensive tool, but a good value. But I won't be buying any preemptively, or just in case.

EDIT: I forgot to add- I was fine in my (one) project that I used precision stones for, but I was really close to the edge of a dovetail way. Do consider holding out for a set of stones that has an angled side which is able to fit inside of any dovetails that are part of your project. It's more sides ground, more expensive of course, but if a square stone isn't gonna fit.... You just bought a set of expensive paperweights.