info needed for turning excentric

[tel]

Keep up Tel, I mentioned Marv in my first reply, linked to the program in my second an its beed discused in about half the posts ;D as it won't work on a mac.

J

*bang* Well so you did! Now how did I miss that? Must be having one of my, erm ... not better days!

 

[Blogwitch]

Don't worry Tel, it does get worse.

But one good thing, you also forget your mistakes a lot quicker.


John

 

[lordedmond]

Tel and John

yes Had one myself yesterday made two part both were upside down and backwards , but the worst part is they would not fit ???


ahh well today is a new day so I will try again , now what was the parts I was making and what for


Stuart

 

[bob ward]

lordedmond, seeing that you have ER collets, make yourself one of these gizmos. I find it very handy for turning offsets in the 4 jaw, especially on smaller stock that would otherwise be a PITA to hold properly in a 4 jaw.

 

[lordedmond]

this forum never fails to amaze me with the quality and diversity of the solutions to a problem

Thanks Bob

that I can see as a useful device


Stuart

 

[Ken I]

KP Bob - I'm going to make me one of those - cute.

Ken

 

[Blogwitch]

That has given me an idea for another tool for my lathe, an offsetting ER collet chuck that would be ideal for small jobs such as this.

If the tolerances are kept fairly tight between the slots and studs, it would only move forwards/backwards, so if a line is scribed in line with the middle placed stud, you would just need to measure with your depth gauge or vernier the distance along that line to give you your correct eccentric offset. If you made 4" plates, it should be able to give you over 1" offset.

Have got to make me one these when the chance appears.


John

 

[lordedmond]

John from little seeds oak trees grow

after Bob had posted I was in the workshop and I ended up eyeing up my er 32 collet chuck on its back plate , and The same idea impinged on my one remaining brain cell

we must have had the same vibes


but yes your idea would indeed solve the problem in one hit



Stuart

 

[peatoluser]

For those who want a fixture that will quickly offset larger diameters , then what about this from the archives?
used it as the inspiration to build something similar for my tiag.
http://www.homemodelenginemachinist.com/index.php?topic=1199.0

 

[Don1966]

John why not add a vernier adjustment to your idea. Like a 1/4x 20 screw which should give you .050 per turn.

Don

 

[lordedmond]

if you are going to put in a feed screw to offset the virtual centre , then why not make a back plate with two keys fitted across the dia. with a groove in the er chuck back plate to hold register and allow movement two bolts as in John's COC , should make a fine work holding tool


Stuart

 

[Blogwitch]

That was a quickie idea and sketchup, no more than 15 minutes to do the lot.

It is a very simple fixture, and when made will be perfect for doing the job, just like a Keats angle plate, where you just tap it gently into position.

There would be no need to make it any more complicated than it already is.


John

 

[lordedmond]

Sorry John

I was just brainstorming

I think the KISS principle is the way to go

as of now the job is paralysed by analysis

I was looking for a quick and dirty way to do the job without having to change over the chucks not a big job but like you my movement is restricted

Stuart

 

[Blogwitch]

No apologies needed Stuart, as you say, 99% of the time, KISS is a perfect way.

Why complicate things when you are already onto a winner.

I used to work a lot on one off machinery, and it was my job to look at it to see if the performance could be improved.

Most of the time, I could remove lots and lots of unnecessary parts, and still get it to work just as well, if not better. Only then would I start to look closely at the machine to improve it's performance.

Start off with the basic, and once it reaches the point where it does the job well, leave it alone, anything else usually just complicates things.


John