ballen
Diamond
- Joined
- Sep 25, 2011
- Location
- Garbsen, Germany
I had some time today and since I have not heard back from Richard about this, I went ahead on my own. Originally I had planned to remove material from the lower half of location 4 (just beneath the grinder wheel casting). But after I got the parts off and looked at them, they were too long and too wide for my grinder and for my surface plate. After that I decided to remove material from the upper part of location 2 (rotary table just above machine casting). Here are the bottom and top:
To get a reference surface I first ground the non-working surface above the dovetail, using the rotary plate as a reference. This surface was originally planed and still had the planar marks. By grinding it parallel to the rotary plate, I get a reference surface which I can then use for milling and grinding the rotary plate to a different height.
Then I milled off about 480 microns (about 0.019"). I did this using multiple passes of a small carbide end mill because that made it easier to compensate for some "belly" in my milling machine.
Then back to the grinder. The part is twice as wide as my grinder, so I needed to do half, then rotate and blend. Note that in both the milling photo above and the grinding photo below, I am using the reference surface created earlier to clamp the part down.
The result is not perfect but better than the other alignments in this part of the machine. I had thought about deepening the relieved center portion when I had it on the mill, but I did not want to "erase" the machine number stamped onto the casting, and since the facing part is relieved, I decided not to relieve this part further.
The hold-down dogs no longer had enough range, but they had 14mm holes and a 12mm eccentric drive, so I bushed them in to 13mm. I made the bushings by lightly knurling some 14mm steel rod then boring it out to 13mm. I coated the bushings with permanent loctite and squeezed them in with a vise. Not pretty but works well!
Here it is, 0.52mm = 0.020" lower than this morning.
To get a reference surface I first ground the non-working surface above the dovetail, using the rotary plate as a reference. This surface was originally planed and still had the planar marks. By grinding it parallel to the rotary plate, I get a reference surface which I can then use for milling and grinding the rotary plate to a different height.
Then I milled off about 480 microns (about 0.019"). I did this using multiple passes of a small carbide end mill because that made it easier to compensate for some "belly" in my milling machine.
Then back to the grinder. The part is twice as wide as my grinder, so I needed to do half, then rotate and blend. Note that in both the milling photo above and the grinding photo below, I am using the reference surface created earlier to clamp the part down.
The result is not perfect but better than the other alignments in this part of the machine. I had thought about deepening the relieved center portion when I had it on the mill, but I did not want to "erase" the machine number stamped onto the casting, and since the facing part is relieved, I decided not to relieve this part further.
The hold-down dogs no longer had enough range, but they had 14mm holes and a 12mm eccentric drive, so I bushed them in to 13mm. I made the bushings by lightly knurling some 14mm steel rod then boring it out to 13mm. I coated the bushings with permanent loctite and squeezed them in with a vise. Not pretty but works well!
Here it is, 0.52mm = 0.020" lower than this morning.
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