FpNC Jig Grinding

Need to finish grind the part shown below. Material is 8620 and the part is carburized and hardened to give a surface hardness of RC 55-60. Because of the shape and size of the part (Deckel gearbox part by the way) i opted to finish grind...not enough to hold on to to hard turn.



Base shaft was turned and the eccentric pin milled on the NC using circular interpolation before going to be hardened.

Here is the basic setup:
Part held in a 5c collet in the index spacer....not using any indexing here , just the collet and lever action draw bar to hold the part in one position.

I am using the a UPA3 "Wally" boring head. The grinding umit is an NSK "Planet 500" air powered jig grinding turbine. I don't have an "LK" so this is my solution. The NSK setup is pretty slick. Comes in a wooden box that carries the air regulator and lubricator. The gadget off to the side is a 2-4-6 block clamped to the table to provide a stable base and height for the dressing unit. This is also an NSK item. Has a micrometer dial that moves the diamond in and out so you cam control the amount dressed.
This is a critical element n any grinding operation but very important here where the power of the grinder is limited. Need the stone to freely cut and that takes a fair bit of dressing to keep it sharp.



Here the setup has been changed to allow grinding on the short eccentric nub of the part....more or less the same as doing the longer section. It is also important here to provide a relief at the intersection of the shaft and the "web" so as to allow grinding off the part and getting a good square corner......

Note the paper to keep flying grit off the machine ways.



Close up of the short section.....





The stripes showing in the close up are marks made by the lube oil from the turbine getting on to the part surface....they wipe off.

Lower edge of the stone in close photo shown to be a bit rough...i used a "norbide" stick to dress the face with a center relief so i could also grind the face of the web of the part....I
believe that is the reason the edge looks a bit rough...works fine.
Cheers Ross

Ross, how much time did you need for making that set-up and after that, the grinding work itself?
I am surprised with the tooling that long, you got that smooth surface.

Interesting pics, thanks for sharing.
Since that part is not out of a Deckel NC, I wonder what the problem is your trying to fix and which machine is effected. Or is it true that Singer is farming the more intricate work out to you now?? Haha.

Great set up. Pure nostalgia. This was the most enjoyable part selling high tech equipment to entrepreneurs, tool rooms and R&D departments.
The ingenuity of solving problems with material at hand and the interchange of ideas.
Cheers,
Arno

Martin
I could be mistaken, but I'm pretty sure that part is the shift linkage for a flip head machine, like a 1985 FP4NC.

There is a cam track on the underside of the 6300rpm mounting plate (the one that slides on top of the Y ram) that this part slides in.

When the head slides back and forth, the eccentric nub moves in the track and rotates the part. The bottom "fork" is connected to the spindle drive inside the Y ram.

When the flip head is pulled forward (to use the vertical spindle) the "fork" pulls the gears forward and shifts from horizontal drive into vertical drive according to the position of the head. (vise-versa when the head is slid back)


Nice work, Iceman!

Steve

Steve,

I would NEVER have guessed that.
I have now taken apart 2 transmissions of the earlier type. I did not know that about the flip head design.
Need to dig in manuals now....

Colt45 said:

Martin
On the 6300rpm/slip head machines (unlike the preceding NC machines) only one drive spindle is running at any given time.

Steve

Click to expand...

Steve,
Are you sure? I think the horizontal spindle runs all the time. The squeal from my horizontal spindle persists when I'm using the vertical head.
RKlopp

Pretty ssure, let me check
Maybe it's because mine is in a semi state of disassembly....

You are right, Russ, I edited my post to correct my mistake.

Ross, the images on your original post have disappeared, any chance of retrieving them?

Here you go:
Need to finish grind the part shown below. Material is 8620 and the part is carburized and hardened to give a surface hardness of RC 55-60. Because of the shape and size of the part (Deckel gearbox part by the way) i opted to finish grind...not enough to hold on to to hard turn.








Base shaft was turned and the eccentric pin milled on the NC using circular interpolation before going to be hardened.




More to follow.
Cheers Ross

From the original post:
Here is the basic setup:
Part held in a 5c collet in the index spacer....not using any indexing here , just the collet and lever action draw bar to hold the part in one position.

I am using the a UPA3 "Wally" boring head. The grinding umit is an NSK "Planet 500" air powered jig grinding turbine. I don't have an "LK" so this is my solution. The NSK setup is pretty slick. Comes in a wooden box that carries the air regulator and lubricator. The gadget off to the side is a 2-4-6 block clamped to the table to provide a stable base and height for the dressing unit. This is also an NSK item. Has a micrometer dial that moves the diamond in and out so you cam control the amount dressed.
This is a critical element n any grinding operation but very important here where the power of the grinder is limited. Need the stone to freely cut and that takes a fair bit of dressing to keep it sharp.



Here the setup has been changed to allow grinding on the short eccentric nub of the part....more or less the same as doing the longer section. It is also important here to provide a relief at the intersection of the shaft and the "web" so as to allow grinding off the part and getting a good square corner......

Note the paper to keep flying grit off the machine ways.



Close up of the short section.....







The stripes showing in the close up are marks made by the lube oil from the turbine getting on to the part surface....they wipe off.

Lower edge of the stone in close photo shown to be a bit rough...i used a "norbide" stick to dress the face with a center relief so i could also grind the face of the web of the part....I
believe that is the reason the edge looks a bit rough...works fine.

Hope this helps....
Cheers Ross

Almost 10 years later, that part gets worked several times a day, every day- works perfectly and no signs of wear last time I looked in the gearbox. Thank you, Ross.

Ross, awesome setup, thanks for photo update!