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Anybody familiar with Drukov grinder? Also vibration analysis.

eKretz

Diamond; Mod Squad
Joined
Mar 27, 2005
Location
Northwest Indiana, USA
I just picked up a nice little tool post grinder locally, has ID and OD spindles, a well as a tiny little taper in the end of the O.D. spindle that takes miniature adapters for itty-bitty I.D. grinding. Never heard of the brand but it appears to be pretty well made. Google seems to show that a few have been auctioned but no real info other than that. Says Brno, so I'm guessing it's Czech in origin. Anybody used one? Worth hanging onto?

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Says Brno, so I'm guessing it's Czech in origin.
"Guess"? You should visit!

Moravian, if you want to get fussy. Present-day, the name b'long a boilermaking firm!

DRUKOV Brno - Produkty

I'd bet that the arms maker, CZ or the machine-tool builder, ToS, would know something about the grinder. They'd have been likely users, times gone by.

Both have staff superbly competent in English.
 
The geared section mates with a worm connected to the round aluminum handle on top. I think it's eccentric - the handle has graduations in 0.01 mm (~0.0004"). Must be for finishing so you don't have to use lathe cross slide or turn the compound way over to get fine infeed. No idea about the graduations by the wheel end of the spindle yet. No manual, so gotta play it by ear and figure it out as I go.
 
The geared section mates with a worm connected to the round aluminum handle on top. I think it's eccentric - the handle has graduations in 0.01 mm (~0.0004"). Must be for finishing so you don't have to use lathe cross slide or turn the compound way over to get fine infeed. No idea about the graduations by the wheel end of the spindle yet. No manual, so gotta play it by ear and figure it out as I go.

The language is sorta-kinda-partially readable as-is, but translates VERY well with google. A manual may exist.

From the present-day Drukov website:

History
The company was founded on September 19, 1949 as a metalworking cooperative DRUKOV with facilities in Brno and the surrounding area with a wide range of activities. The main production program of the facility at Cejl 18 in Brno has always been the production and installation of thermal technology.

They were struggling, post WWII. Skilled folks, and desperate at looking for ways to earn a crust. Thermal was in demand. But I wouldn't rule-out it was the same "Co-Op", back in the day as also made that grinder.
 
I found a pdf manual but, as is often the case with technical language, it does not Google translate well. I gleaned a little bit, but mostly it was gibberish in the sections I was actually interested in.
 
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looking at the photos. Looks like the drive motor is rigidly mounted, unlike a Dumore that has a hinge.
Wondering if the eccentric setup is there to tension the drive belt.
Cheers Ross
 
No, the drive motor is mounted on a flange that slides in a slotted fit to tension the belt while keeping the pulleys in alignment. I just spent a few minutes playing with the grinder and the eccentric is definitely for adjusting the depth of cut/size. The aluminum knob has a collar that can be twisted to zero it out that is graduated in 0.01mm increments in diameter, so turning by 1 increment would change diameter by about 0.0004". They're pretty widely spaced so easy to hit sizes in between. I stuck an indicator on the front of the grinding wheel collar, and it turns out the numbers on the spindle itself are increments of 0.1mm in diameter. So every full turn of the aluminum knob rotates and changes the increment on the spindle by 0.1mm in diameter, or actual movement of a little under .002". Pretty cool setup. Definitely a keeper.

The large red screw is a cap that covers another screw in the spindle which from what I can tell with Google translation of the manual is for adding/checking oil. There are two smaller flat-bottom screws that clamp the spindle cartridge eccentric rotation (not the actual rotating while grinding part attached to the wheel), one of which is visible lower than and to the right of the red cap screw.

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if you have specific questions you can mail me the manual. my grandmother was moravian, i might figure out what is says.
 
so bearings are spring preloaded. for inside grinding dress the stone convex by hand. otherwise there is not much.

do you need to know anything in particular? they mention an addapter for grinding cylinders, no idea what that is.
 
Yeah I managed to get that part about convexing the wheel for ID grinding from Google translate, not sure what they would want you to do that for other than reducing area of the wheel in contact at once.

I saw a little about that "adapter for grinding cylinders" too - made about as much sense to me as it did you. I would think a toolpost grinder is generally already for grinding cylinders... perhaps that is referring to the second spindle cartridge I've got for deep cylindrical I.D. grinding.
 
i believe thy say to change the spindle for "cylindrical" grinding. so you have another spindle? maybe its a long one taking larger wheels? interestingly they also talk about "surface grinding" with a saucer wheel. how would you do that?

btw, how did you find the manual?
 
interestingly they also talk about "surface grinding" with a saucer wheel. how would you do that?

Mount it to a planer or mill, rather than a lathe. CAN work better than it sounds with skilled fiddling, and has to do, if resources are slender.

Some optimists have even used shapers, droop and all, and "made it work, well ENOUGH" to get a problem sorted even when the grinder was an ignorant ANGLE grinder!

I kid you not. Shaper and angle grinder. Photos are on PM, somewhere.

You'd have to know clever humans and desperate times?

"Run what you got!"
 
i believe thy say to change the spindle for "cylindrical" grinding. so you have another spindle? maybe its a long one taking larger wheels? interestingly they also talk about "surface grinding" with a saucer wheel. how would you do that?

btw, how did you find the manual?

Yes the second spindle cartridge is visible in the third photo in my first post. It is long, I figured it was for deeper ID grinding. I suppose it could be used for OD work also, but not sure what advantage that would offer over the regular OD spindle. I suppose surface grinding would also be possible in the lathe with a cup wheel and a method to index the spindle. One could probably sharpen the ends of milling cutters too I suppose. Not something I'd really want to do, but if necessity arose...

I found the manual with Google. Took a little searching but it turned up eventually.
 
Drukov Toolpost Grinder

No, the drive motor is mounted on a flange that slides in a slotted fit to tension the belt while keeping the pulleys in alignment. I just spent a few minutes playing with the grinder and the eccentric is definitely for adjusting the depth of cut/size. The aluminum knob has a collar that can be twisted to zero it out that is graduated in 0.01mm increments in diameter, so turning by 1 increment would change diameter by about 0.0004". They're pretty widely spaced so easy to hit sizes in between. I stuck an indicator on the front of the grinding wheel collar, and it turns out the numbers on the spindle itself are increments of 0.1mm in diameter. So every full turn of the aluminum knob rotates and changes the increment on the spindle by 0.1mm in diameter, or actual movement of a little under .002". Pretty cool setup. Definitely a keeper.

The large red screw is a cap that covers another screw in the spindle which from what I can tell with Google translation of the manual is for adding/checking oil. There are two smaller flat-bottom screws that clamp the spindle cartridge eccentric rotation (not the actual rotating while grinding part attached to the wheel), one of which is visible lower than and to the right of the red cap screw.

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These are similar to Grizzly T27400, but the latter seems to be updated to B&S taper hubs and 1-1/4" ID for larger wheels (versus 2.0" ID for Drukov). I just put my Drukov up on ebay, since I no longer have a use for it. Thanks for posting the Manual pdf.
 
You're welcome. I rather hope that it's of considerably better quality than the Grizzly... I've had it apart a bit and it looks pretty nice. Good fits and smooth functioning. It has a 3-phase drive motor, I'll run it off a spare vfd when I finally get around to getting it up and running.
 
You're welcome. I rather hope that it's of considerably better quality than the Grizzly... I've had it apart a bit and it looks pretty nice. Good fits and smooth functioning. It has a 3-phase drive motor, I'll run it off a spare vfd when I finally get around to getting it up and running.

The photo you posted shows a start capacitor, so I doubt it's 3-phase.
 








 
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