Gallery, Projects and General > The Design Shop
3d indicator design
BillTodd:
Well, it's back together. Seems to centre to zero pretty well. There's a tiny bit of dead space ~20um ( from some angles and not others, which is a bit odd ) .
It has just over 3.5mm movement in all directions which is pleasing, since that's more than the previous set-up gave. The 45° slide still feels a little rough (need to be run in).
I'll try to find the time to test it tomorrow .
Bill
AussieJimG:
This is an enthralling thread. I have been watching in admiration of you Bill, for your initiative in starting this project and your determination in pursuing it.
It is really wonderful to watch you track down the errors and modify the design and to see the interaction and assistance from others, particularly PekkaNF. Thanks to all of you.
Jim
BillTodd:
:) Thanks Jim.
This afternoon I just got the thing in the lathe to test it when a mate turned up with a dead motor.
His swimming pool pump had eaten its own bearings (again!) -
'it smells like the motor's dead to me' - I said, :smart:
'no, it's been running fine'
two hours later, after making a sleeve to fit the new bearing on the knackered shaft, we had the motor running....
for about three seconds ! :doh:
Verdict: new pump required
Will try again to get the indicator tested tomorrow :(
BillTodd:
Between phone calls, I manage to do a quick test to see how well the indicator works between faces...
Hmmm quite well, but consistently 17thou off (measuring an inch) - I was expecting an error because of the dead spot in the middle (slack in the ball slide & other parts) but not that much :bugeye:
However, it is consistent, giving the same error in all directions (well the 90, 180 etc. that I tested) so it's a simple matter of adjusting the size of the probe to compensate...
That's where the day peaked :hammer:
Had a phone call - "This 'clip' you want made... Is it really nearly an inch thick and half-a-metre wide ???"
DXF conversion strikes again - 16mm gets changed to 16 inches then converted back to 406mm on import :bang:
I make the probe tip, after a lot of faffing around
Then I manage to break the washer out of the ring while trying to screw the probe in - Of course, it will not go back in with out more faffing - Now I'm waiting for the loctite to set... :bang:
Time for more coffee
BillTodd:
Arrrgh... :bang:
Finally I found time to do some tests. I clamped a micrometer in the tool post and used the DRO's touch probe to give me an absolute zero face then adjusted the mic to give a second face at 20mm spacing.
:scratch:
While it appears reasonably consistent in any one direction ( i.e. once zeroed in a direction it will return to zero within 10um - even if removed from the lathe), it will not accurately measure between faces because of the play in the bottom taper slide (I had to re-ream this after I threaded it, so I guess it's now too big :()
Maybe it's time to throw in the towel ? (I've lost faith in the design)
Bill
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