Centerless grinding questions

[Billk59]

Hello,
I need some advice on centerless grinding. I took a position as a lathe hand at a machine shop and after the lathe work was done they put me on a centerless grinder. I have never ran one of these machines. I was shown the basics and now I’m pretty much on my own. The machine is a Cincinnati EA, and I think the plain bearing type. We are trying to grind 286 hardened stainless rod, about 5/8 diameter. I have the regulator wheel set at 0 degrees. The blade is brass, blade angle is 20 degrees. I’m not sure what is meant by diamond offset. How to I determine how to adjust this? We have tried 3 or 4 different grinding wheels and have been unable to pull more than .005. Presently we are using a silicon carbide wheel on the softer side and of medium density. I have no experience with this type of machining but I’ve done some research and tried to apply it to the job. I’m not sure what kind of wheel to try next and I would appreciate any advice from anyone who has run these machines. I understand they are very accurate and efficient if set up correctly but I can’t seem to find much information on proper set up. We do not have an owners manual. Also, are there any safety issues I should be concerned about?
Thanks for your time.

 

[FredC]

Wowsers. Questions that I have no clue what the answer is. The first shop I worked at had a centerless grinding machine and an old man ran it. He could do stuff that he thought was impossible when he was given jobs and finally did it. The trickiest job I saw him do was step grind a thin wall aluminum part. It had a 7/8 large OD and a 3/8 small OD. He held a couple of tenths on both and kissed the shoulder in one op. Not sure if there is anyone here that can answer your questions. Hopefully my posting will bring it back to the top where someone that can help will see it.
Would like to see you make contact with some old expert that can give you the answers and coach you. If worst comes to worst, several of us use commercial grinders that can do the job for you all. M&M Quality Grinders is a company I use. They grind hypodermic tubing for me and hold a plus or minus a tenth with no issues. My source on the tubing does in house grinding but will not try to hold that tolerance, so I buy the tube and have it sent to M&M.

 

[Conrad Hoffman]

There are experienced people here that will no doubt chime in, but yeah, safety is a huge issue with these things. You don't want to dive in without input from somebody that's experienced. Things can go south in a big hurry!

 

[michiganbuck]

Here is an old PM thread that may help
New centerless grinder operator

I have not had enough centerless experience to be giving advice.

 

[john.k]

I scrapped a very nice #2 EA with all the extras last year,but I still have all the books........the one you need is the thick book that came with the machine........there is also a tool crib size book,which is OK ,but the big book is the one to have.........Incidentally ,I have never heard of using SiC wheel with any kind of hard steel.....I also never heard of using a brass blade with hard steel......Hard cast iron,steel,and mostly HSS....I scrapped 1/2 ton of blades.....thats how many you need. ..I will dig out the books and get the number.

 

[john.k]

By the way...the grinding wheel ,and in mine the regulating wheel bearings are called Filmatic......a rocking contact multiple shoe system........look up Filmatic Bearings....

 

[boslab]

Never used one, seen one, spoke to the lady that operated, she said somthing about the control wheel is the bit that does the biz, I’ll pass on that but there must be books on the subject somewhere?, they’ve been around a long time
Mark
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[tdmidget]

Hello,
I need some advice on centerless grinding. I took a position as a lathe hand at a machine shop and after the lathe work was done they put me on a centerless grinder. I have never ran one of these machines. I was shown the basics and now I’m pretty much on my own. The machine is a Cincinnati EA, and I think the plain bearing type. We are trying to grind 286 hardened stainless rod, about 5/8 diameter. I have the regulator wheel set at 0 degrees. The blade is brass, blade angle is 20 degrees. I’m not sure what is meant by diamond offset. How to I determine how to adjust this? We have tried 3 or 4 different grinding wheels and have been unable to pull more than .005. Presently we are using a silicon carbide wheel on the softer side and of medium density. I have no experience with this type of machining but I’ve done some research and tried to apply it to the job. I’m not sure what kind of wheel to try next and I would appreciate any advice from anyone who has run these machines. I understand they are very accurate and efficient if set up correctly but I can’t seem to find much information on proper set up. We do not have an owners manual. Also, are there any safety issues I should be concerned about?
Thanks for your time.

I have run EAs. They are good machines. Yours is almost certainly older than you are. You NEED a manual, if only because the lack of one is an OSHA violation.
I assume this is thru feed grinding.How long are the parts?
The silicon carbide wheel is appropriate for austenitic stainless steels. It will work for other steels
To see the work rest (blade) height it should be half the part diameter plus 8 7/16" above the machine surface where the workrest assembly sits Just use a good rule to measure this, it's not that critical.
The regulating wheel inclination would probably be around 2-21/2 degrees to start.
The diamond set over should be 1/2 to 5/8 inch. Open the regulating wheel guard and look on the discharge side for the diamond. Clean it up and you will see that it is graduated in inches.
With these adjustments made, dress the regulating wheel and grinding wheel.
Set the guides so the part enters with no obstruction and has the same contact all the way across.
Use a wooden dowel or similar to start the part into the wheels. It should travel smoothly across and out.

Safety. These machines can kill you and never grunt doing it. Keep you hands and anything else you value out of the grinding area. ALWAYS disconnect the power to make any adjustments or repairs.
Watch Ebay for an OPERATOR manual. The parts and service is good to have but does not tell you how to run or set up. If you don't find one soon contact me.