What are you machining?

[Dcal]

A new backplate for my 160mm 4 jaw

Did you make the back-plate from scratch?

I have three to make and can burn out a few mild steel blanks.
I know the blanks are cheap but fancy the challenge (Totally new to this machining lark)

Nice Boxford by the way

 

[decca]

No i bought a cast iron blank from Chronos.
For the cost it wasnt worth mucking about.

 

[grim_d]

So you spurred me on @decca .

I've had a chronos blank sitting for about 6 months now.

Backplate came out fine. A little chatter marks on the radius. A big inclusion on the threads, not a great casting really.

Even though I only faced off the bare minimum to clean up the faces I still ended up with the spindle nose sticking through the backplate by 0.4mm

The big 4 jaw held the smaller one fine and a small recess was cut to accept the protrusion.

Mounted, cleaned up and ready to go, very happy. 0.01mm runout on the body and barely even a flicker on the face. Now just to get on with the other million projects.

 

[decca]

Excellent work. I had some holes in the casting too but managed to get rid of them with the bolt holes. Suppose the blanks are a bit rough. Does the job though.

 

[grim_d]

Yeah they are fine, apart from the mess turning cast iron! I've got another backplate to make for a 4" 4 jaw for my dividing head but I think I'll make that one from steel.

 

[ronan]

Cast iron is messy old stuff to machine, also abrasive on your machine slides and surfaces, so make sure you clean up really well.

 

[brightspark]

Cast iron is messy old stuff to machine, also abrasive on your machine slides and surfaces, so make sure you clean up really well.

I cover the bed with a cloth to catch most off the dust of cast

 

[Johnnybravo]

View attachment 145561 View attachment 145562 View attachment 145563

One half done . Am a better machinist than photographer. It's all symmetrical,I promise,lol

Saw the first parts made today. Looks promising

 

[grim_d]

To be pedantic you didn't machine those...



Came out good though!

 

[Kram]

Interested to know is there an inner form and if so, how do you get them off?

 

[grim_d]

I'd suspect the form spins whilst the liquid rubber is injected so no need for an inner.

 

[Johnnybravo]

To be pedantic you didn't machine those...



Came out good though!

To be even more pedantic , look back a couple of pages and you will see I machined the tool !

 

[Johnnybravo]

I'd suspect the form spins whilst the liquid rubber is injected so no need for an inner.

Has an inner core. No spinning involved

 

[Johnnybravo]

Interested to know is there an inner form and if so, how do you get them off?

Yes there is an inner core. Look back a couple of pages,there is a photo of the inner core.How do you get them off?
Witchcraft coupled to the correct magic words...most of which begin with a 'f'.......

 

[Hood]

I would imagine their will be enough stretch in the rubber to pull off the internal form quite easily. Now if both ends had been the small dia that might be slightly harder

 

[Johnnybravo]

Compressed air and a twisting motion has them off,but it's not easy !

 

[Hood]

Compressed air and a twisting motion has them off,but it's not easy !

My friend (no longer here) used to have a rubber moulding place, was mainly solid stuff like dog toys and trawl net bobbins but he did do some gaiters and the like, he said it was hot horrible work but then again he didn't mind too much as he was mostly in his office

 

[Johnnybravo]

I am glad I only do the tooling !

 

[grim_d]

To be even more pedantic , look back a couple of pages and you will see I machined the tool !

I know, just yanking yer chain!

Must of missed the post of the core though.

 

[Dieselman 63]

The two knobs from my Fobco Star had been opened with pliers by someone previously. Idiot! Today I surfaced them and re-knurled - first time knurling! I’m suitably pleased, can’t wait to put them back on the machine