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+--- Thread: Rotary project, maybe???? (/thread-795.html)
RE: Rotary project, maybe???? - claudef - 09-27-2012
(09-26-2012, 05:54 PM)Rickabilly Wrote: I'll say it,
Wow, beautiful work Claude.
No Vernier scale yet? not that I'm picking, just curious
regards
Rick
The reason why there is no vernier is that I had not figured out how I would index the part with the accuracy needed.
My spin indexer has 36 holes on a 3.5" PCD... Now if you remember correctly, my worm is 40:1 ratio, 9 deg per turn. To read one deg on the dial I rotate it 40 deg's. There is 10 graduations @ 4 deg's spacing in between those larger marks.... So the vernier spacing need to be at 3.99 deg, 7.98, 11.97, etc.
To do this with the spin indexer I need to improvise.
If you look at the drawing attached, the large circle represents the 3.5" pcd of the indexer. Now if I put a pin in one hole and rotate the plate and pin onto a stack of Joe-Blocks and scribe one line then increase the stack by the amounts shown to scribe the other lines. I would be using the Spin indexer as a sine plate (somewhat).
Do you see any flaws in my approach.. Your comments would be welcomed.
Claude
RE: Rotary project, maybe???? - claudef - 09-27-2012
(09-26-2012, 08:01 PM)f350ca Wrote: Impressive work Claude, can only imagine what you'll be producing on it.
I have no idea what I will use it for. I needed it in the past but now that I have it I might never need it.
It is nice to look at, I give you that.
Claude
RE: Rotary project, maybe???? - Rickabilly - 09-27-2012
Hello Claude,
Your logic is pretty sound, but I will need to check the math, and if you could clarify are you using the blocks the space the rotation off of one pin hole> if so your block height will need to make an isosceles triangle with the centre of rotation being the peak and the two equal angles will be the primary location pin and the moving pin.
I know how hard it would be to make sense of that text, so, give me a day and I'll come back to you with a better description/picture and or a better method.
Best Regards
Rick
RE: Rotary project, maybe???? - f350ca - 09-27-2012
Claude,
If my math is any good, probably not after a long day you may have the first project for your rotary table.
The hand wheel is divided in 9 degrees with 10 ths so 90 divisions. 360/90 4 deg apart. To make the vernier you need to divide 11 divisions on the wheel into 10 so 44 degrees of the wheel dived by 10 is 4.4 degrees per division on the vernier. Without the vernier you can index the table to 1/10th of a degree so your there. With the vernier you'll have 1/100th of a degree.
RE: Rotary project, maybe???? - claudef - 09-27-2012
Rick,
I used Cadkey to plot the lines and to dimension the intersection. The 3.5" PCD measurement I stated is close but not accurate. This was used to test my theory only. So don't spend too much time on the math till I get more accurate measurements. I am off to Ottawa for the weekend so this project is definitely not going anywhere for a while.
Thanks for your help Claude
RE: Rotary project, maybe???? - stevec - 09-28-2012
Hey Claude, you'll be close enough to drop in on Greg, although the thought of you two getting together is too scary for the rest of us dullards to imagine.
RE: Rotary project, maybe???? - Rickabilly - 09-28-2012
As it turns out I didn't get around to it today Claude, but Greg is looking down the same track I was thinking about, I will get around to it ASAP which for me is never very fast.
Regards
Rick
RE: Rotary project, maybe???? - claudef - 10-01-2012
Finally took the time to properly measured the PCD of my spin indexer 3.543 dia. and the center height is 2.765 from the base.
Also recreated the Cadkey drawing using the proper dimensions.
Took a picture to better represent what I want I was trying to explain in text on my last post.
Hope this clarifies what I would like to do.
RE: Rotary project, maybe???? - Rickabilly - 10-01-2012
Yes Claude that setup looks really suitable, if you could add angular dimensioning to your cad drawing it would save me a whole heap of math work to verify the work you have already done, It really is an angular change we are trying to verify, incidentally do you have slip guages for this setup or are you intending to grind the block to the correct height each time?
If you are going with the latter may I suggest a screw jack and micrometer might be a whole heap easier to do the same job.
Best Regards
Rick
RE: Rotary project, maybe???? - claudef - 10-02-2012
(10-01-2012, 08:10 PM)Rickabilly Wrote: Yes Claude that setup looks really suitable, if you could add angular dimensioning to your cad drawing it would save me a whole heap of math work
Rick
Rick... all the lines are 3.99 degrees from each other as you can see on the attached picture. I did not insert all the line angular dimensions, I figures half was enough.
I am in no rush for this, I have no projects in the near future that will require a rotary table and if I do I dought precision to the second decimal point would be required. However, It would be nice to add that final finishing touch.
Thanks Claude