We have bought an old cincinnati 220-8 centerless grinder. I was
wondering if anyone could help me with reconditioning tips. Or if i
could get my hands on a service manual.
I think there is some problem with the hydraulics.
any help would be welcome,thanks,
What is the nature of the problem? I've never run a 220-8, but I think
they are quite similar to the older #2 or #3 models. The one and only one I
observed certainly appeared to be so. I can only assume that you know that
the wheel head won't start until the machine has developed hydraulic
pressure, which lubricates the Filmatic bearings.
How much rebuild do you intend to do? There's not really all that much
to go wrong with centerless grinders, assuming the spindles are in good
condition. Their precision generates from the method of application more
than anything else.
One thing that is critical is that the dressing heads are capable of
providing a straight dress. If you can't profile the wheel properly,
you'll have a difficult time getting your parts to spark properly, often
leaving ugly feed marks, or not leaving the wheels under their own power.
That's not a good scenario. Is the dressing head on the grinding wheel a
profile type that runs a template, or does it rely on the ways for form?
The type with the template are far superior, allowing for a modified wheel
Keep your eye on ebay------I have seen manuals offered several times. If
you are not familiar with a centerless grinder, you should get a manual, or
find someone that has run them to instruct you of the principles involved.
They're a strange machine that don't necessarily function as you might
assume. Knowing the center distance to the wheel from the blade rest is
all important to making proper setups. Do you have that information?
Thanks for the reply. Like you said not much can go wrong with the
I got an electrical guy to come and check the machine.
All the motors work:
- the grinding wheel motor
- the regulating wheel motor
-and the hydraulics motor
but the regulator wheel actually does not rotate. so could that be
because hydraulic pressure is not developing. the motor is working
is there any lever to engage it etc...
i checked for a manual but one old and torn one is available for 100$!
I don't think the regulating wheel has anything to do with the hydraulics.
The only thing I can think of is that the transmission is out of gear. At
the bottom of the regulating wheel end do you find one or more levers?
They'd be below the feed hand wheel, on the right hand side of the machine,
in the base. On the older type machines that's where the transmission for
changing the speed of the regulating wheel is located. You might check to
see that nothing is out of place.
I've never worked on that end of a centerless, but somehow I get the idea
that the regulating wheel is chain driven. Yeah, I know, that sounds crazy,
but it operates at a very slow speed, so a chain wouldn't be much of a
problem and would be a positive drive, something that is important to
successful operation. Please don't take my word for it, it's been years
since I last saw a centerless, and even more since I've run one. If it's
not, feel free to correct me, and tell me how it's driven. Can you turn
the regulating wheel by hand? (Don't try that with the grinding wheel
The filmatic bearings are, to the best of my recollection, split sleeve
bearings that operate under hydraulic pressure, which lubricates and also
controls the amount of clearance. From that you can deduct that they are
pressure sensitive, and it's the main reason that the wheel head doesn't
start up immediately. You must have hydraulic pressure for the bearings to
function properly. They're reputed to be the most precise method of
supporting the spindle. I recall having to adjust them on one machine
when I couldn't get it to spark out properly. The wheel dressing attachment
wasn't a profile type, and had considerable wear, dressing a slight hollow
in the wheel. That's the worst possible condition you could expect if you're
trying to get a good finish without feed marks. It likely goes without
saying that the machine was quite old, otherwise the dressing head wouldn't
have been so worn, so adjusting the filmatics helped, but didn't eliminate
the problem. As I recall, the bearings are adjusted under power. The
manual addresses that function, but it's highly unlikely one would ever have
to mess with them, especially if the machine has low miles.
I'm sorry to say I don't know anyone that owns a centerless any longer, so
I'm not much help where a manual is concerned, but if you intend to keep
yours and use it regularly, the $100 cost for the tattered one could prove
to be a bargain. There's lots of things you need to know about a
centerless in order to get the most from it. Are you familiar with their
first of all thanks.
yes i am familar with the opration of centerless grinders. we have
about 17 machines. and only one of them is hydraulic and none of them
is a cincinnati.
-so if the grinding wheel is running then is the hydraulics working?
a man who came to look at the machine oday said that the hydraulics is
totally not functioning.
maybe ill need to get the manual afterall. its very difficult to get a
man experienced in a cincinnati here.
like you said the regulating wheel must be only a gear problem , ill
You're certainly welcome, but I'm not convinced I'm helping much.
Very good! I was hoping I wasn't talking down to you. That wasn't my
Absolutely, although there could be some fluky thing that prevents the
regulating wheel from working. As I said, I've only seen the later
machines, I've run only the earlier models, so yours could be different.
There is a pressure switch that prevents the wheel from starting until there
is proper hydraulic pressure. That I know for sure. You can't walk up to
a Cincinnati centerless and hit the start button and get the wheel to run
immediately. I don't recall how long it takes for the system to get up to
speed before the wheel will start, but it's more than a couple seconds.
I don't agree, not if the grinding wheel runs. That doesn't prevent some
portion of it to be buggered, though.
You're certainly welcome, Sachin. Please keep me posted on your progress,
and feel free to correct anything I've stated that isn't right. I'm
trusting to very rusty memory.
another man came to have a look at the machine. He said that the
hydraulics need to be fixed.
so getting that done. any tips.... what i should look for when he fixes
anything else likely to go wrong.
Frankly, I didn't really think it was a hydraulic problem, so I don't have
an opinion. I'm not sure I'd know what to look for, or where to look for
it at this point. It might be that that particular model is substantially
different from the old ones, and my thoughts aren't even in the ball park.
One thing for sure, unless he's very good at hydraulics, he could spend
considerable time on the machine with no progress. This might be an
excellent time to get a manual that provided hydraulic circuitry.
Let me know what you discover. Very interesting.