how to machine domes

[feartheride]

What do I need to know if I want to machine a set of domes.What is the easiest way to machine out the same amount.I can cc them when done.I don't have them in hand but If I remeber they are a radius surface so maybe make a template and try to match it. I think it is a 26 cc and want 34 or so. The 26 was producing about 215 psi and want it down to 180 .
The squish band is good

 

[kingnothing3]

I was just trying to figure this out myself. the template isnt a bad idea but it doesnt sound exacting enough.

also, all I need to do to make a 701 dome fit a 760 is widen the squish band correct?

 

[Big Kahuna]

isn't it like 7 lbs per CC?

 

[stanton]

you have cnc lathe experience?
if no you shouldnt.

 

[Big Kahuna]

why would it have to be a CNC lathe, why not a regular lathe?

 

[stanton]

i guess it doesnt have to be a nice parabolic dome like they come.. manual lathe doesnt cut curves.

 

[Big Kahuna]

I wasnt thinking about the domes section, just the squish band.

 

[SUPERTUNE]

Yes, You can use a normal lathe with a adjustable stop or like what we use, one with a digital readout.
Our X-Metal lathe machinist made a special spinning tool holder so we could do the radius in the chambers.
Oh, by the way... shoot for about 4-5 cc's, not 8 cc's like you stated.

 

[QuickMick]

i guess it doesnt have to be a nice parabolic dome like they come.. manual lathe doesnt cut curves.

This is a myth about a manual lathe doing the work.

Its the machinest and the tooling he uses to get any cut, cut correctly, not the manual lathe its self.

 

[QuickMick]

What do I need to know if I want to machine a set of domes.What is the easiest way to machine out the same amount.I can cc them when done.I don't have them in hand but If I remeber they are a radius surface so maybe make a template and try to match it. I think it is a 26 cc and want 34 or so. The 26 was producing about 215 psi and want it down to 180 .
The squish band is good

I was just trying to figure this out myself. the template isnt a bad idea but it doesnt sound exacting enough.

also, all I need to do to make a 701 dome fit a 760 is widen the squish band correct?

If you guys do open up your domes, can you post picts for us that want to cut our own domes open too. I have thought about this but never looked into doing it. OD, depth, Arc. ect.

 

[750SX]

Featheride, IMO it isn't worth messing with since so many shops can do it for a small fee

 

[stanton]

Yes, You can use a normal lathe with a adjustable stop or like what we use, one with a digital readout.
Our X-Metal lathe machinist made a special spinning tool holder so we could do the radius in the chambers.
Oh, by the way... shoot for about 4-5 cc's, not 8 cc's like you stated.

oh yes i forgot about those:dunce:

 

[feartheride]

Featheride, IMO it isn't worth messing with since so many shops can do it for a small fee

it's all about doing it because you can and doing it without having to wait for them to be sent out and back.

 

[augustaf]

I was just trying to figure this out myself. the template isnt a bad idea but it doesnt sound exacting enough.

also, all I need to do to make a 701 dome fit a 760 is widen the squish band correct?

That is only sort of correct! With the larger bore you would have to remove 3 cc's to have the same cranking pressure as before. Just widening to 85 mm would not achieve that.

 

[Shifty]

For a manual lathe you could rotate the compound to achieve a concave shape, but I think it would be too shallow, instead you could use something like this... It would need to be set up differently to perform a concave cut.

 

[rossthaboss11]

i had a local machine shop cut out mine from 28cc to about 30 cc. they did an excellant job the thing looked like a mirror and my compression came out perfect

 

[feartheride]

For a manual lathe you could rotate the compound to achieve a concave shape, but I think it would be too shallow, instead you could use something like this... It would need to be set up differently to perform a concave cut.

YouTube - Turning a ball (knob) on the lathe.

Thanks a good find I will make a jig