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SeymourDumore

Diamond
Joined
Aug 2, 2005
Location
CT
Guys, I have a Keller cutter grinder, pretty much the same as in this thread: https://www.practicalmachinist.com/forum/threads/keller-die-sinking-machine.334890/

Does anyone by any chance have any idea on how to use this darn thing?
I know the shop it came out of used it daily to put make custom bullnose endmills or ball mills and the like.
Problem is that shop is no more and I cannot find anyone that knows anything about them.
I very much would like to use it for the same purpose ( since I already have it and all the collets that came with it ), but need a little guidance on how.
Google turned up precious little using the "Keller" or "P&W Keller" words, but perhaps there are other brands of grinders that work in the similar fashion from which to get a clue.

Thank You
 
The Keller I am familiar with is basically much the same as a Monoset.
likely you can find the Monoset manual.
The tool holder swings to arc a concave or convex radius. I believe the clearance angle is made by raising and lowering the wheel and finding the clearance on the radius/arc of the wheel.
So you should have/make a gauge that edges off the front of the tool side table that shows the center of the swing, with that position you set zero and travel away from the amount to make the concave or convex radius. Good also to make some angle hand held gauges for various radiuses. KoLee had a book comparing the wheel diameter and how far above or below to make a certain clearance..don't know where you will find that book..
Ops time for dinner..I will try to get back to this
Biuck
 
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Cincinnati Monoset
see page 7. The desired radius is set over the center of the swing tool holder..and is advance or retarded ahead of the center or behind the center to give the concave or convex radius. The tool cant be tilted for clearance because that would change the radius shape, but the raising or lowering of the wheel with the tool radius horizontal to the swing allows the radius to be a true radius..The secondary is made the same way by increasing or decreasing the position/height of the wheel arc to increase the clearance... it is not uncommon to slightly change the off-center amount to get a straight primary to secondary straight land.

Hand-held clearance angle gauges are like a 6" scale with an angle cut at the end so one can just hold that gauge to bump the wheel to find the place on the wheel that gives the desired clearance angle, one could trig that out but +- a half degree is the drill for cutter clearance and that is close enough.

Another but less common method is to stand a diamond horizontally and use the swing to dress the radius into the wheel for a plunge grind of the radius..problem is that the secondary clearance needs a slightly different radius..this method is better when the operator can make a nice looking secondary by hand.
often a good tool guy will make the radius by hand and the plunge to take very little stock so saving the diamond dress for a longer time.
 
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Thank you Buck!
That actually helps out a whole lot!

What my current ( immediate ) project is ( what actually brought this whole thing up now ) is I need to grind 1/8 dia carbide blanks with various tips.
Some are bull nose with different radiuses, some are tapered in various degrees with various bullnose radius and some are tapered into ball end of various radiuses.
IOW I don't even need to worry about clearance angles at all.

SO first order of business: Figuring out how to find the centerline of the workhead and the swivel axis.
Then the question: Can a bull nose or Full R tip be generated with a straight faced wheel?
Page 7 shows formed wheels. I can understand it for concave shapes, but technically a straight face should be able to generate an external, convex radius no?
Again, in my case the radiuses will be at the tip of the workpiece, nothing at the "shank" to worry about.
 
OK, but where would you prefer it?
General or Abrasive?


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Think Snow Eh!
Ox
What? do not understand the question.

SeymourDumore is in for a leaning experience to say the least.​

And Buck is like go here, go there, move this slide xx yy and to him so simple to do to get that rad where it belongs, tangent and in size.
 
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Aw Schidt!

I was going to move this and then clean up the "move" stuff.
But as soon as I clicked "move" I had this revelation that I can't edit it in the other board. :willy_nilly:

Should have cleaned it up FIRST, then moved it.
My bad! :o
(Kan't git good hep these days)

Sorry to whoever runs this board....


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Think Snow Eh!
Ox
 
Likely that dome at the center of the swing tool holder is pretty centered and centric. you might indicate it's od and if a good center put a cap on it with a post sticking up with a ground flat to the half or center line..that way you have right/left and straight out.
I think you can grind a couple of insert side angles and grind a radius of perhaps 220* around..I don't see it grinding a full circle, grease pencil, and then blending the second half but that would be tricky.
*Grinding a ball nose, or a rod with a couple of angles and a ball or pointed end is logical for that grinder of the rod or held part can turn.
Type 1 / a simple straight wheel with the flat (OD) facing the swing end would seem logical..to run two angles and a nose of a radius or point seems doable if the tool work head turns/rotates..

This similar grinder seems to not have a tool-holding device that rotates
 
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Thank you guys for the help.

My machine is of the kind which Buck posted.
Similar to the Monoset, but let's face it, it ain't no Monoset.
Also, any and all videos of a Monoset ( that I've found so far ) are done by people who know about as much of a Monoset as they know about the inner workings of the space shuttle.

With that said...

I finally got the wheels and the collets to run nicely true, and I am ready for the first, simplest task: grind a ball end onto a .125 precision ground blank.
No OD, no taper, just a plane-jane ball on the end.
Spent a couple of hours trying to wrap my head around finding the center of the swivel ... well, my head is what's swiveled now.
Did end up with a partial bullnose on the edge of the blank, but it is nowhere complete and it was done on the side of the wheel instead of the face.

Can someone please give me a nudge?
Again, .125 blank needs a ball nose ground onto it, and it doesn't even need to be perfect, can be incomplete by as much as 5 degree on either end.
 
Thank you guys for the help.

My machine is of the kind which Buck posted.
Similar to the Monoset, but let's face it, it ain't no Monoset.
Also, any and all videos of a Monoset ( that I've found so far ) are done by people who know about as much of a Monoset as they know about the inner workings of the space shuttle.

With that said...

I finally got the wheels and the collets to run nicely true, and I am ready for the first, simplest task: grind a ball end onto a .125 precision ground blank.
No OD, no taper, just a plane-jane ball on the end.
Spent a couple of hours trying to wrap my head around finding the center of the swivel ... well, my head is what's swiveled now.
Did end up with a partial bullnose on the edge of the blank, but it is nowhere complete and it was done on the side of the wheel instead of the face.

Can someone please give me a nudge?
Again, .125 blank needs a ball nose ground onto it, and it doesn't even need to be perfect, can be incomplete by as much as 5 degree on either end.

There used to be a guy on YouTube that had some real good videos with a Monoset clone but for some reason he deleted them. I haven't found any others. Monoset manuals give a pretty good basic primer of how to use the machines too, I think there are some downloadable ones at Vintage Machinery.

For a plain round ball nose your first step should be to get your blank centered on the radius pivot axis (centerline of the ball). You can use a dial indicator for that or just touch the grinding wheel on either side of the blank by turning the radius axis pivot and touching off on both sides, looking for equal (barely there) sparking and split the difference on the dial - or again, with an indicator.

Next, make sure your grinding wheel centerline is coincident with your part centerline. (If using the wheel OD rather than the face anyway). Not higher or lower.

Then spin grind the ball. I generally use the OD of a type 12 wheel for midsized stuff, sometimes the OD of a cutoff wheel for smaller stuff. Type 1 I don't like unless I don't have to worry about crashing the wide wheel into the part. On a full round ball it would be fine, just watch the wheel corner if you get any wheel wear, as the wheel will form itself somewhat to the radius that you're grinding. Even with an endmill you want to spin grind the radius so you know it's true, and you only have to rotate the workhead through around 90° (a little less) that way. After you get it roughed in you'll want to come back and touch off the side of the blank again to reset your wheel location in case you have some wheel wear, then give it a finish grind.
 
Spent a couple of hours trying to wrap my head around finding the center of the swivel ... well, my head is what's swiveled now.
Did end up with a partial bullnose on the edge of the blank, but it is nowhere complete and it was done on the side of the wheel instead of the face.
Side of the wheel works the same as the face except for tilt of the swing axis and it's effect on tool clearance.
Side of the wheel means up/down for rakes. Front of wheel and it fixed by tilt and part load.
All swing machines/fixtures work the same. Bullnose and you are offset from centerline.
Wheel distance to pivot point makes the rad size. Part shift or these axis must blend to the front and side you want.
So what went wrong? You say partial? What did it look like? Was it the right sized rad?
After touch off or other tricks generally you do a backed out test cut and then move things from this knowing.
Taught this to many. It is very confusing until you hit that Ah-Ha moment.
I have seen and let people struggle for 8 hours trying to put a nice .015 rad on the end of a VDB lathe grooving tool.
 
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Good morning Seymour:
I hate to totally screw up your thread, but have you considered just wire EDM cutting the shapes you need on the ends of your blanks?

I cutter grind a fair bit too, and even having a ton of experience grinding, I now default to wiring my form cutters because it's easier and more accurate, and I know you have wire EDM machines in your shop so you could easily do it that way too.

I understand that part of what you hope to do is to get good with the Keller, and I acknowledge that ground cutters last longer than wired cutters, but having screwed around with both methods, for my kind of work it's no contest.

If this recommendation completely misses the point, forgive me.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com
 
The swing gauge has be such that it locates the center of the swing coming straight out of the tool holder.. the right and left can be found by working off the wheel width center.
Only off the pivot because every tool length coming out of the work head changes that center....The straight-out one.
 
Step one. Grind a radius, any radius.
Measure it. Now you know how far to move the wheel towards or away from the pivot point. Do this first.
You may need to comp this a bit if at say 20 degrees of tilt.
Step two. Wheel position is now fixed for rad size and tool height. Do not change it.
Touch off the part front and end using the slides above the rotate axis so they kiss the wheel where you want.
Everything now is above the swing guy.
Easy peasy. I do not use swing gauges.
Where most get into trouble is moving the base wheel to try to get a blend. Then the rad size is wrong which leads to madness.
I do remember my early swing fixture setups.... massive frustration.
 








 
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