New Semi-Automatic 6x18 Surface Grinder Options?

coffeetek · Jun 16, 2020

We are in need of a semi-automatic surface grinder. Semi-automatic 6x18 size would do. Job is to make some of the parts, top and bottom face of 3" and 4" diameter disc 3/8" in thickness, parallel to within a tenth or two.

I am only aware of Okamoto and we are looking at ACC-618DX3 which is fairly expensive. With magnetic chuck, coolant and dust system, wheel balancer and magnetic separator comes out to about $45k. Seems high.

Any other options we should look at that could do the job? We are interested in new machine only.

Mike1974 · Jun 16, 2020

coffeetek said:
We are in need of a semi-automatic surface grinder. Semi-automatic 6x18 size would do. Job is to make some of the parts, top and bottom face of 3" and 4" diameter disc 3/8" in thickness, parallel to within a tenth or two.

I am only aware of Okamoto and we are looking at ACC-618DX3 which is fairly expensive. With magnetic chuck, coolant and dust system, wheel balancer and magnetic separator comes out to about $45k. Seems high.

Any other options we should look at that could do the job? We are interested in new machine only.

I'm not sure on price, but the Okamoto is a fine grinder. I ran a bigger one, 12x18 chuck I think.

Chevalier makes a semi-auto, as well as Kent, but no idea on prices.

coffeetek · Jun 16, 2020

Mike1974 said:
Chevalier makes a semi-auto, as well as Kent, but no idea on prices.

I am looking into these. They are at least 50% cheaper than Okamoto. I have no clue how good they are and would appreciate if someone who has one posts about their experience.

greggv · Jun 17, 2020

Well, we have an Okamoto, and wouldn't dream of a different kind of grinder. You usually get what you pay for.

AD Design · Jun 19, 2020

Have used several Okamoto wet grinders in that size and consider them a very good SG. From back in the late 1980's a Mitsui seemed to be a better grinder. Nothing wrong with the Oko, just a personal preference for Mitsui. No idea if Okamoto has improved but I doubt Mitsui quality has fallen off. There are other brands but I've no experience with them as new.

Mike1974 · Jun 19, 2020

coffeetek said:
I am looking into these. They are at least 50% cheaper than Okamoto. I have no clue how good they are and would appreciate if someone who has one posts about their experience.

I *think* (pretty sure the chevalier and okamoto have more or less the same color scheme and layout?) I have run a chevalier. Couldn't say if one was better than the other, been a lot of years.

I find surface grinding is as much technique and proper wheel selection as much as it is the quality of the machine...

coffeetek · Jun 19, 2020

AD Design said:
Have used several Okamoto wet grinders in that size and consider them a very good SG. From back in the late 1980's a Mitsui seemed to be a better grinder. Nothing wrong with the Oko, just a personal preference for Mitsui. No idea if Okamoto has improved but I doubt Mitsui quality has fallen off. There are other brands but I've no experience with them as new.

Thank you for lead on Mitsui. I got the quote and its even more expensive than Okamoto. Most likely, we are going to go with Okamoto.

AD Design · Jun 19, 2020

coffeetek said:
Thank you for lead on Mitsui. I got the quote and its even more expensive than Okamoto. Most likely, we are going to go with Okamoto.

-Not surprised the Mitsui is more expensive, I felt it was a better grinder and apparently they do too. All the shops I worked at must have felt the same about price and bought the Okamoto for wet work. For working to .0001 (as you mentioned) Mike1974 posted good advice in it being about technique and wheel selection. Get the details right and it's repeatedly doable, get the details wrong and .0001 will be inconsistent. Is this about size, parallel, or both that need .0001 accuracy?

coffeetek · Jun 19, 2020

AD Design said:
-Not surprised the Mitsui is more expensive, I felt it was a better grinder and apparently they do too. All the shops I worked at must have felt the same about price and bought the Okamoto for wet work. For working to .0001 (as you mentioned) Mike1974 posted good advice in it being about technique and wheel selection. Get the details right and it's repeatedly doable, get the details wrong and .0001 will be inconsistent. Is this about size, parallel, or both that need .0001 accuracy?

Just parallel. Yes, I know, its all about attention to detail.

michiganbuck · Jun 19, 2020

Even on a brand new surface grinder I would put a strip if masking tape at the inside parting line where tha long travel moves on the below structure... most of the grit that gets into the ball or roller area goes in that way...Oil way machines, even plastic scraped ways tend to wash out some /most grit..if I had my rathers I would choose an iron scraped oil way machine... if anyone even makes such a a machine. My buddy bought an Okamoto for high precosion one and few ups..and said it was a very good machine.

Very often tenths work with wheel break down and heat is a chalange..getting used to spotter grinding is the best way to do close for mulitiple parts, with with making good time. If you have to chack a part three times to make .0002 that is not good.

cameraman · Jun 20, 2020

coffeetek said:
We are in need of a semi-automatic surface grinder. Semi-automatic 6x18 size would do. Job is to make some of the parts, top and bottom face of 3" and 4" diameter disc 3/8" in thickness, parallel to within a tenth or two.

I am only aware of Okamoto and we are looking at ACC-618DX3 which is fairly expensive. With magnetic chuck, coolant and dust system, wheel balancer and magnetic separator comes out to about $45k. Seems high.

Any other options we should look at that could do the job? We are interested in new machine only.

I think Okamoto is the sweet spot for price verses performance.

I'll rummage about for some quotes.

I have to admit I find Okamoto's product line and price structure a little confusing.

I think their basic form grinding platform "NC" one with hydraulic table and double V scraped Vee's is about $47K base price.

So yeah better than Chevalier not as "Special" as Mitsui .

Would you take a risk / "Plunge" on second hand machines... ?

Base price on the ACC-618DX3 is around $29K , the accessories certainly add up a bit.

coffeetek · Jun 20, 2020

cameraman said:
Would you take a risk / "Plunge" on second hand machines... ?

Base price on the ACC-618DX3 is around $29K , the accessories certainly add up a bit.

I would not want to risk it with used machine. We are doing production and while not huge numbers I don't want to deal with interruptions of fixing used machine and fiddling with it. Just not worth it to us.

cameraman · Jun 20, 2020

coffeetek said:
I would not want to risk it with used machine. We are doing production and while not huge numbers I don't want to deal with interruptions of fixing used machine and fiddling with it. Just not worth it to us.

I understand... Sometimes you see some pretty sweet machines once in a while. - Not really bankable though.

How about a planetary style (double sided) fine grinder ?

Introducing the FDG-700 Double-sided grinder

FDG-700 FDG-700

^^^ No affiliation, have not used this particular piece of equipment.

michiganbuck · Jun 20, 2020

I completely understand the desire for a brand-new machine and with money /cost not a factor get the beat you can. I won’t knock the Okamoto because my buddy bought one and said it was a good machine. Actually, I think they are overpriced about 25%, Mitsui a very decent machine is also overpriced. Most ball and roller modern machines should have the table taken off and a good cleaning every 5 years or so.
Who knows if a surface grinder is best for grinding your job? (Job is to make some of the parts, top and bottom face of 3" and 4" diameter disc 3/8" in thickness, parallel to within a tenth or two.] are you going to hire a grinder hand or expect anybody to make good parts. Perhaps put 8 parts on the chuck and grind two sides to +- OO1 size?
What is the material, How much is the take, how close the thickness, how many a week/month/year?

*A decent rorary grinder is faster than a surface grinder for this kind of work.

Here is a used machine I would trust for as good as new...when they have scraped and tested the machine.
Parker Majestic 8x18 Surface Grinder W/Power Elevation - tools - by...
QAQ

Agree this Parker is Not an automatic.8-18 hand machine...but just to show there are some good used machines.

Here rebuilt B&S , one of the best machines build..
Brown & Sharpe Micromaster Surface Grinder Rebuild Services

bryan_machine · Jun 20, 2020

I've never called for a quote, so have no idea where they fall in price range, but Parker Majestic does list a 6x18 (though it's maybe full CNC)
Their website suggests they may also have 6x18 manual.

michiganbuck · Jun 20, 2020

I know the have a 618 manual..I had a brand new one to break in..it was a nice machine..>.100 thow on the cross feed . They do remanufacture them also.
Cnc related to parker
Freedom Series CNC
Manual machines..some of the older one included.
Parker Majestic - Rebuilding

drcoelho · Jun 21, 2020

Mitsui making the best surface grinders in your required form factor.

michiganbuck · Jun 21, 2020

Do understand that automatic can mean the operator is relived of cranking handles but may need to stand there while the grinder grinds to near size. I say near because wheel breakdown makes finish to +-.001 To .005 not very difficult, but to .001 to .0001 can be difficult. The operator still needs to measure the part or eyeball a spotter to make size.
A programable grinder with a Renisaw or Marposs probe can be programed to make size and end the program. This so the operator can do other tasks while the machine finishes the load of parts.
Most name brand modern grinders can run 10 years or more with a mid-term cleaning so the cost of a probe is justified for a production part.
Some grinders are automatic and manual so that type grinder might be considered if one-ups and few -ups might be needed.

For one and few ups a good grinder hand can make parts faster with not programing a CNC.

Example of a automatic/manual/programable grinder.
programable surfae grinder - Video Search Results

EmGo · Jun 21, 2020

drcoelho said:
Mitsui making the best surface grinders in your required form factor.

And you would know this because you have thousands of hours in running a surface grinder in a production environment ?

michiganbuck · Jun 21, 2020

Also consider that some/many parts need two sides grinding because relaxed stresses may make them go out of flat..and very carful de bugging before setting on the mag... de-mag after grinding..perhaps corner treatment like remove sharp edge or bevel.

QT: [With magnetic chuck, coolant and dust system, wheel balancer and magnetic separator comes out to about $45k. Seems high.] likely add $3 for a probe. $5K and not even a DRO thia does seem high..I think there are many name brand machines as good...

New Semi-Automatic 6x18 Surface Grinder Options?

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