Cutter grinder information

[michiganbuck]

From the clearance chart plate at the below post you see the above or below wheel center one would position the wheel to achieve the desired clearance. (Diameter X clearance x 89 = above or below.) That would suggest having the wheel OD facing the part.
RE: 3 inch wheel x 7* x .89 + 185 (actually 185 but plenty close enough.)
That keller was a rare machine likely because the also rare Cincinnati radius/profile grinder and the Cincinnati Monosei were easier to use/ understand.
Making a pivot location pointer/ gauge should make quick setup possible.
Using the Od of a grinding wheel will make a curve acr in the part..using a recessed wheel. a flat-dressed cup or dish wheel on the side face will make a straight /Flat grind.
The angles plate is the 4th photo going down.
Hi everyone, A friend of mine just purchased an interesting old machine, and i was hoping to find out a bit more about it. We haven't been able to find any reference to it so far. The tag says "Keller Die Sinking Machine" by Keller mechanical engineering Corp. It's equipped with a weldon...
www.practicalmachinist.com
The Cincinnati radius/profiler machine had a straight (Type 1) wheel set verticle that would rotate and travel ahead and behind its pivot center to achieve a radius..The part be raised or lowered to the where to achieve clearance.. The wheel travel (left and right)could be set free left or right travel so a trace could follow a form template..one could follow a form, make a radius and continue to make more of a form..It was a little tricky because the operator had to eyeball judge the position of work head pivot being well centered..often one was lucky to make .001across the form and radius. I have only seen and used one of these machines..likely hard to find one today.
The Monoset was the survivor, likely because it could make a helix and became popular for that feature. A good shape Monoset can do almost anything.

 

[michiganbuck]

The center setting gauge would for getting started with setting the swing place, and traveling from that place to size a radius ...just putting a piece of tape on the swing and using a ballpoint pen to make circles or lines that would be a help for finding a ballpark swing center location..

 

[michiganbuck]

Here is the Monoset operator manual

http://manuals.chudov.com/Cincinnati-Monoset-Grinder-Manual.pdf

Note the height-centering gauge in Figure/photo #24
Rotating the swing with watching/indicating the diameter of that gauge can locate the center of the swing. bring the cutter to that post and advance forward one half of the post diameter is the swing pivot center, advance the cutter, or back away for a convex or concave radius. Agree is only applicable when the work head (spindle) is in the horizontal position.

 

[implmex]

Hey Buck:
Got a question for you that's related to the topic of this thread.
It's a technique question.

When you're swinging a radius and you approach the stops you've set, what's your favourite technique to avoid whanging into the stop and gouging a divot into the cutter.

I've found it's one of the most difficult transitions for me to get perfect, and I've tried several different methods.
Best I've ever been able to do, is tear down the machine, make sure the pivot runs as smoothly and lightly as I can, and then run the swing arm onto the stop using no more than one finger oriented so my finger wants to flex as soon a I touch the stop.

Even so, if I inspect what I've ground on the shadowgraph: at 50:1, I can still see maybe half a thou defect right at the transition unless I get lucky.
If the machine's not just about perfect, it's almost impossible to get it smooth.
Before the wire EDM, I even built a swing arm setup using radial needle roller thrust bearings together with a pair of angular contacts to try to get the motion as light as I could.
It was pretty good, but I could never get it perfect.

So what's the secret?

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com

 

[michiganbuck]

I have done a ton of things for a cushion stop, a couple of bandaids, a piece of tape with a plastic hose under it, bumping the stops, coming to a wood shim, and then pulling the shim for a careful final travel, and more.
When surface grinding to end travel in the part I used popsicle sticks adding more and more going deeper (down grinding with long travel to the stop).

 

[eKretz]

I put a little piece of soft silicone rubber on the end of my stops. Then I can just bump into those, it decelerates softly and I can just use a little more pressure to get to my endpoint. It actually repeats pretty well and the sparks tell you pretty well when you're at the right spot if your in an internal corner too.

 

[implmex]

Thanks Guys:
I've tried that too but I was not able to get a perfect transition no matter how careful I got.
It's always where the radius tangents into the straight, whether making tapered ball cutters or making bullnose cutters.

If I make it really soft, I can't tell exactly where the stop is.
If I make it harder, I get the divot, even if it's just microscopic.

So you guys are clearly doing something better than I am...time to figure it out, for those moments when I want to make a quick cutter on the Deckel and am too lazy to set up the wire.

Thanks for the tip, michiganbuck and eKretz!
It's one of the best things about this place...I can almost always get an answer to my question...no matter how arcane it is.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com

 

[michiganbuck]

I think it is really difficult to get perfect...mine aren't likely better than yours...perhaps not as good.
Yes, I got best/perfect with CNC grinders
My buddy Donnie made near-perfect single blades/cutters by dressing the full form into a wheel., but he had a custom-built non-catalog fixture.
I did some of that by using a Royal Oak grinder...using crushable grinding wheels

 

[eKretz]

There's always a little bit of a fiddle near transitions. Usually it's not significant enough to matter on my stuff. But you work on super tiny things so I can see where it might be more of a problem.

 

[implmex]

Hi again Guys:
Actually, I'm fussy about these things because I used to be a moldmaker.
If your cutter was even a little bit deficient, the polishing burden on a mold core or cavity went up astronomically.
So I was always striving to make better cutters so I wouldn't be sitting there half of forever, hand polishing out the toolmarks with abrasive stones.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com

 

[CarbideBob]

I am not fully understanding this blend/overcut problem.
Round (endmils) or flat tools like VDB or top notch or simple inserts.
No doubt that wire EDM is easier .

 

[implmex]

Hi CarbideBob:
I have found that when I swing a radius it always overshoots a tiny amount when I reach the end of travel and hit the stop.
So it leaves a tiny defect right at that junction.

I was hoping others have a better technique that I for transitioning from swinging a radius to traversing a straight flute.
It seems they do what I do...they just do it better than I do.

That's it.

Cheers

Marcus
www.implant-mechanix.com
www,vancouverwireedm.com

 

[SeymourDumore]

OK, just to chime in with my progress...

The Keller is not a Monoset. That was already established.
As such finding the center of pivot is a PITA, so I took the easy way out and used a tooling ball.
That went well.
Thankfully my project did not require absolute accuracy, so after finding the center I started to experiment with broken 1/8 endmill shanks to achieve my goal.
After ruining a whole bunch and throwing another bunch at the wall in frustration, I think I've got at least a faint hint at how it works.

In any case, I did manage to properly grind 2 different sizes in qty 2 each, and they worked like an absolute charm!
Marcus did get the idea correct, these are intended to be facegrooving tools.
Previously we've talked about these and toyed with the idea of wire cutting them.
The problem is that the material I am cutting is Titanium, so a dead sharp cutting edge is an absolute must. Unfortunately not really achievable with the wire.
Anything less than razor edge makes a wicked burr and/or result in an instant tool failure.
These ground bits worked flawlessly.
Shaped the tip and then ground the business end to the half flat in the same setup.
Once the first piece was dialed in ( that took a while .... ), the second piece got done in less than 2 minutes.

 

[implmex]

Hi SeymourDumore:
That is great to hear...I'm very glad it worked out well for you in the end.
But now that I know more about what you're trying to do I have another alternative that's worked better for me when I have an accurate radius to swing but cannot wire it for the same reason you just stated, ie, you need a better edge than the wire EDM can give you.

I use a radius dresser built for shaping grinding wheels and I built an attachment for it that allows me to put my cutter blank in the place where the dressing diamond normally goes, but up off the centerline of the wheel so the wheel periphery makes side relief automatically as I swing my blank.
In my case it's a pretty elaborate rig...I happen to have an Optidress on my surface grinder so I can set angles and radii with ease and I can see my progress under the microscope as I'm grinding the tip of my cutter.
If you don't know what an Optidress looks like: it's a radius and angle dresser that mounts permanently on the suface grinder wheelhead and you can swing it, you can displace it laterally and you can move the pivot point around in relation to the edge of the wheel.
Here's a link to a Youtube video:

So it has exactly the motion control you need, and the 10X scope and readout is a bonus.
Making cutters like you describe is a doddle with a rig like that, but you can do it almost as nicely with any radius dresser on the market...just not quite as conveniently.

So if you have a surface grinder and a radius dresser you can make these cutters very easily...much more easily even than I can with my Deckel SO single lip cutter grinder, and you can get them very accurate without all that much effort.

Think of it as similar to your Keller, but smaller, more easily usable and more accurate.
I bought mine for 500 bucks off EBay because these things are now obsolete technology.
Pretty much anybody who does form grinding nowadays uses a CNC dresser, so you can find these old school mechanical dressers pretty cheap.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com

 

[CarbideBob]

I use a radius dresser built for shaping grinding wheels and I built an attachment for it that allows me to put my cutter blank in the place where the dressing diamond normally goes, but up off the centerline of the wheel so the wheel periphery makes side relief automatically as I swing my blank

You dress/shape resin or vit bond diamond wheels for carbide tool grinding with this?
Tried many flavors of this dress/true method and no so much working out well for me.
We have used a moly stick for an outside wheel rad in a similar swing setup with a scope but it is painful.

 

[implmex]

Hi CarbideBob:
No I don't dress a diamond wheel with the Optidress, I pull out the single point diamond and put in a pre-split carbide blank where the diamond would normally sit.
I have a diamond wheel in the grinder spindle dressed in the conventional way with a brake dresser.

So I'm using the Optidress as if it were a cutter grinder work head.
Of course it only works for turning tools...I'm not making milling cutters with it.
I like using it because it's super easy to set my radii and angles, I can inspect it while I'm grinding on it, and it is nice and tight.
If I grind on the periphery of a narrow wheel, I can swing a full 180 degrees so I can make a skinny blade with a radius on the tip if I want one.
It's like having a work head with readouts on it and I can peek down the scope and see what I'm making and if it's correct without having to dismount it and put it up on the shadowgraph.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com