# HSM Surface Grinder



## Brass_Machine (Jan 12, 2008)

All this talk of of surface grinders has me wondering... right now I don't have the room for a surface grinder. However, I have some back issues of HSM (from 2006) that has some plans for a bench home shop grinder. Has anyone here built one? Any opinions of it?

Eric


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## Mcgyver (Jan 14, 2008)

Eric, I haven't built one, but I'd be fairly confident in saying don't bother. a surface grinder has to have very precise bearings, better part of a G note or more and a precision balanced spindle. without this, you're not going to get a good finish. think about whats going on. depth of cut is measured in tenths so acceptable run out has to be a fraction of a tenth or it'll show up in the surface finish. and its dynamic run out spinning a heavy wheel at 3k. you need very high class bearings and a very rigid structure to make that happen. then start worrying about ways. you'll need to know how to scrape (with hardened steel strips over the scraped surface) and make hardened cylindrical rollers.

I don't think you could build one, at least a high quality one, for twice what you could buy a used one for. 

they are great for making your tooling, I use basic mild steel and send it out for a deep case. nice. but do we really need hardened tooling on the home shop? not a necessity. I've made my tooling mostly, so my SG hardly ever gets turned on. because our uses don't demand the same wear resistance we can achieve the same results using soft steel and techniques like scraping

and they are dirty. if you grind dry you need to wear a mask and if you grind wet you'll taste all night whatever chemicals are in the coolant.

talk you out of it yet? 

imo what hsm's do overlook and what makes a major contribution to work quality is a tool and cutter grinder. Having sharp drills, end mills and precision ground threading tools is a big step up. having both, i would recommend getting a t&c grinder before a surface grinder...it gets use more often and has become indispensable - never cut with a dull cutter again! a surface grinder is one of the tools to add when a perfect one comes along and you're feeling flush, not something to go out shopping for and not reasonable as a diy project, imo


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## macona (Jan 15, 2008)

A surface grinder would be on my next want list. But I need more room before I can even think about that one.

I dont think a surface grinder is something worth building. Depending on where you are you can get a machine in decent shape with stones for 5-700.

Sometimes they even give them away to get them out of the way, unfortunately no where near me.

A good grinder for home may be the "Quorn" for sharpening tooling. Casting kits run from 250 to 300 I think. I believe http://www.martinmodel.com has the kits.


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## compound driver 2 (Jan 15, 2008)

Hi
I built the Quorn many years ago adn its used most days for one thing or another. Once you add a few extras it becomes a machine you wouldnt want to be with out. I first read about in in Model engineering many many years ago and would recomend it to any one considering a cutter grinder.

As for surface grinders they do have there uses and for some jobs are the only answer. Would I have one? well no I can farm it out to the guy three doors down he gets the mess and the expense. As for building one, no certainly not I wouldnt have the spare time or the money to put into bearings.

Cheers Kevin


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## Spin Doctor (Jan 16, 2008)

While I would consider a SG more useful than a drill press (if you have a mill what do you need a DP for?) there is no way i think I would consider building on from scratch in a hpme shop. The fit required on the shaft in the spindle if using angular contact bearings almost demands using a cylindrical grinder to hold the diminsions and _concentricity_. Balancing the whole rotating assembly will be an excercise in hair pulling. Scraping the table ways and the cross slide way and the vertical ways and holding everything flat and square. Well if you have any hair left when you start you won't when you finish. Better to buy one even if in rough shape and rebuild it. Connelly's Machine Tool Reconditioning has a whole section on Sufrace Grinders. But that said what are some of the things you could do to avoid some of the pitfalls. 

1) Use bronze bearings instead of Angular Contact Ball Bearings. Abrasive surface grinders used a tapered bronze bearing for the front of the arbor that was adjustable to set the clearance. IIRC they run about .0005". The rear was held in a set of lower grade 72XX I think. Its been a while since I rebuilt one. 
2) Perhaps linear ball ways could be used for the x/y axis

If I was looking for one I think I'd look for a Harig. A pretty simple machine and one that really doesn't need the factory base.


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## cfellows (Jan 16, 2008)

What about the "swing" surface grinder, also featured in HSM a number of years ago? It was a bench grinder that's vertically mounted on a column and operates by swinging over the work which is fastened to a stationary table. It seemed like a pretty neat idea for small work.

Chuck


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## Spin Doctor (Jan 16, 2008)

cfellows  said:
			
		

> What about the "swing" surface grinder, also featured in HSM a number of years ago? It was a bench grinder that's vertically mounted on a column and operates by swinging over the work which is fastened to a stationary table. It seemed like a pretty neat idea for small work.
> 
> Chuck



Commonly called a butt or end grinder. But not to be confused with a vertical spindle surface grinder. The industrial ones are mostly used for squaring up the ends of stock. At least that's what we used one for. Some guys refered to it as the "hand Blanchard". But these types of grinder cannot be used for grinding up to a shoulder or form grinding. Plus they put a lot of heat into the part. Perhaps the best type of small grinding machine for the small shop is a universal tool grinder. Usefull for sharpening tools, doing OD work either between centers or in chucks, surface grinding and with an auxilary spindle ID work.


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