First bit of Tooling

Hi Gents

I got a set of ER32 collets with the WM18 mill and although it had a collet spanner it did not come with a 36mm spanner for holding the collet shaft whilst doing the collet nut up.

Nice little beginner opportunity to put the Mill to work! Knocked up some drawings in Fusion360 and proceeded with the project.
I used steel for the handle, but only had a piece of aluminium plate for the spanner head. Obviously my concern was the steel handle would simply break out of the aluminium under side load so made a interference fit collar to provide further strength and support.

I thoroughly enjoyed making this little item from design through to the final product on both lathe and new mill.
I know its only a spanner but when I used it for the first time it certainly brought a smile to my face!

G

Edited By Grant Nicholas on 15/01/2016 20:25:03

Nice job 👍

Gosh thanks Grant! I was thinking about exactly this problem today and your solution is better than the "spanner" I was going to wastefully bodge from a bit of rusty 3/8" plate tomorrow.

Ta,

Dave

That's a much nicer bit of kit than the usual one punched out of plate. And, you did it!

Pete

Thanks John!

@Dave. My pleasure! If you like, I could send you the technical drawings for the entire spanner in PDF format?

G.

Happy new spanner

H

Grant, how about a short article for Neil on this piece of tooling? I have exactly the same problem with my ER32 collet chuck used on my lathe.

Regards,

John.

.

+1

from 'requirement' through 'design & manufacture' to 'testing'

... it should make an excellent article.

MichaelG.

Drop me an email if you are interested, Grant.

[email protected]

Neil

.

I like it.

Nick

Thanks for all the kind words gentleman. I am extremely honoured you think it worthy of a article in the MEW magazine!

I have just realised how disappointed I am that I did not take any pictures of the steps in the project, I usually do this, but in this case got so absorbed in the build that I did not bother..... oh well nevermind, whats that saying about hindsight......

I shall get in contact with Neil to find out whats involved.

Cheers

Grant

Well done Grant, nice looking spanner.

George.

Hi Grant,

Many thanks for the offer of a pdf but I think I can make one using the info you've already published. My version will be much more utilitarian than your nicely finished prototype. I might publish a photo if it's not too horrible!

Cheers,

Dave

Grant

The fact that you did not take pictures need not be a problem. Just make it again - taking pictures as you go. You can then either offer it as a prize or, if you are anything like me, keep it safely somewhere in case you lose the first one!

Norman

( ps - the problem with the second option is remembering where the "safe place" is ! - maybe I' m a bit older than you though)

Nice work Grant! There's some interesting stuff in F360, especially when you consider it's free for the likes of us. Sounds as if it may be a bit premature to talk about the CAM elements that are waiting for you but there is some interesting content in the "simulation" tab too. Here you can do full Finite Element Analysis (FEA) to see how close to the bone the design is with the sorts of loads you might expect to see.

If you take your existing design and create some small features to denote where the spanner will contact the nut, you can apply some contact forces and simulate the stresses and strains that represent what the spanner will see in the worst case - will it be close to failure, is there a weak area where there is undue stress etc.

It's under Simulation > Study > Static stress. You place loads, constraints (fixed faces for instance) and set materials (aluminium jaws and steel handle here), then click Solve. You can display stress, strain, displacement etc.

I haven't taken long to model your tool very accurately (it's really not very close) but this gives an idea of how quick and easy it is to do some FE Analysis. My jaws were 25m wide and 15mm thick, so probably not as beefy as yours.

The end of the handle is fixed and I assumed a torque of 5Nm (3.8lbft) and a nut dimension of 44mm A/F. With a hex head this results in equal and opposite forces of almost 1400N at the line contacts between the nut and the jaws (1400N x 36mm = 5Nm) - these are the blue arrows.

The yield stress of aluminium is around 15-20 MPa, so in my example where it predicts about 70MPa peak stress, the jaws would have turned to toffee. You can see where the highest stress is - and where it would be possible to beef up the section to improve it.

Hope you find this interesting!

Murray

Edited By Muzzer on 16/01/2016 18:35:41