Questions about surface grinder

[7milesup]

I remember seeing some information on here regarding the best choice for a SG with regards to the wheel size. 12" is cheaper than ? Or maybe it was the other way around. Does anyone have insight on this?

I have been contemplating a surface grinder for quite some time but not sure how often I would use it. It seems like you can find them for practically nothing on some auctions, which I believe may have more to do with the (lack of) desire in moving them. Also, what is the biggest point of wear on them. Obviously the spindle needs to be dead nuts on, but can they be rebuilt (the spindle that is). Do the table traversing mechanisms wear out too I would imagine?

Here is a link to an auction with a few of them on it... Surface Grinders Catagory.

 

[benmychree]

If the spindle on a surface grinder is bad, don't buy it, likely it would cost more to rebuild than the grinder is worth. Perhaps you should find a need for one before contemplating buying one, but size wise, start relatively small, like 6X12 or 18" that uses wheels 8" and under.

 

[Bob Korves]

7" O.D. with a 1-1/4" bore is the most common size wheel used in home shops. They do come in various widths. My B&S 2L grinder will only hold 1/2" wide wheels within the wheel guard. I do not find that size limiting for the work I do. They come up to 1" wide, and even wider with a rebated bore. 12" wheels are nice, but a lot more expensive than 7". Home sized machines sometimes are 6", the upside is that worn used wheels from 7" grinders can have a new life on the smaller machine, but lower surface speeds from the smaller wheels make the same wheel act softer, and vice versa. You would be limited to the same 3600 rpm maximum that seems standard for 7" SG wheels.

If the spindle on a surface grinder is bad, don't buy it, likely it would cost more to rebuild than the grinder is worth. Perhaps you should find a need for one before contemplating buying one, but size wise, start relatively small, like 6X12 or 18" that uses wheels 8" and under.

Agreed. Rebuilding a precision grinder spindle is not the same thing as changing the wheel bearings on your pickup. Sometimes the bearings can cost many hundreds for a set, sometimes they are obsolete. The cleanliness, balance, and preload is important. Get help if you don't know how to tell a good spindle from a bad spindle, or just walk away. Commercial repair of surface grinder spindles is extremely expensive.

 

[Bob Korves]

All machines wear out eventually. Surface grinders are no exception, and they live in a gritty environment. If the grit gets to the slides, it will eat them alive. If the machine is not meticulously taken care of and cleaned and lubricated, life will be shorter. Missing grit guards are a red flag. A SG can be tested as easily as a milling machine, but to a higher standard, and many SG tables just lift off the grinder, only gravity holds it on. If the one you are looking at is that way, take the table off and see what is going on with the table and carriage ways, and how much grit and grime is in there.

 

[7milesup]

Perhaps you should find a need for one before contemplating buying one, but size wise, start relatively small, like 6X12 or 18" that uses wheels 8" and under.

WHAT??! Why would I do that? That is no fun. LOL.

On a serious note, thank you for the replies so far regarding wheel size. That was the info I was looking for. Of course, I live in the middle of nowhere, so looking at these grinders is usually a 5 hour round trip for me, so if I ever bought one, it would have to be very cheap and I would go into it knowing that it might be worth scrap prices. I do think that having one would be great though. Like most hobbyists, tools sometimes sit around for a while between uses but those few times one uses it, it sure is nice to have.

 

[Richard King 2]

I drive to Hayward in the no snow months to my cabin and if you have issues I would gladly help you out being neighborly if you need to borrow my bearing heater or centering machine, no problem. The bearings my buy from Bearings inc.net (no space) over by Green Bay. Be sure to get a matched set of #7. I also use Mobil Grease # 32 or 28. Can buy a 1 pound can. Don't buy Chinese bearings off ebay. Their are some fake bearing sellers there. If you do check the number of people who have bought and gave then positive feedback.

 

[Bob Korves]

Most of the less expensive, home shop size surface grinders for sale I looked at were really scrap metal. Around here, scrap iron sells for about $100/ton, you deliver. You have to get it for less than free to make that worthwhile. At the very least, try to find one that has a spindle that turns smoothly and freely with zero play in the bearings, and has all the parts that came with it new, and hopefully with more tooling included. The wheel adapters (hubs) for the grinding wheels for the most common style go for about $75 each new at a honestly good sale. Used ones are often rusty and abused. You would ideally like to have a hub for each grinding wheel you have on hand, a dozen would just about be a comfortable number. Oddball wheel adapters for many old grinders are unobtanium, and they are precision made, not easy to do a good job on them if you are a machinist rookie. Anyway, do your homework and hold out for a decent machine in good working condition at a decent price, with extra wheels and tooling. Take your time, it can take years in this neck of the woods. Decent surface grinder tooling is usually quite expensive, even used.

 

[7milesup]

I drive to Hayward in the no snow months to my cabin and if you have issues I would gladly help you out being neighborly if you need to borrow my bearing heater or centering machine, no problem. The bearings my buy from Bearings inc.net (no space) over by Green Bay. Be sure to get a matched set of #7. I also use Mobil Grease # 32 or 28. Can buy a 1 pound can. Don't buy Chinese bearings off ebay. Their are some fake bearing sellers there. If you do check the number of people who have bought and gave then positive feedback.

Wow! Thank you! That is a very generous offer. I would love to talk to you more at some point.

 

[Cadillac STS]

Where would you find a new "Home size" surface grinder? Similar to the question of buying a used Bridgeport versus a new Precision Matthews mill. Or is there only used machine hunting for that?

 

[Cadillac]

Where would you find a new "Home size" surface grinder? Similar to the question of buying a used Bridgeport versus a new Precision Matthews mill. Or is there only used machine hunting for that?

I quess it’s all about location. CL Chicago has a handful for sale right now, and auctions are abundant around here too. Just a matter of looking.
New “ home sized” you’d be importing that and who knows about quality. 6x12 is about the smallest and readily available used. Problem with newer stuff is weight and construction. They’ve removed all the weight they can and they just seem cheap and floppy.