Cooling fins on a mill

[remout]

I drank too much Stirling kool-aid and now feel the need to build one. I don't have a lathe but I have a cnc mill. I want to build the Jan Ridder Bas design that has aluminum cooling fins. I have many questions as I'm not a Machinist.

Is there anything wrong with turning the mill into a vertical lathe via a R8 shank lathe chuck?

The cooling cylinder has four holes through it and the cooling fins are flat on two sides and round on the other two. I'm thinking I should proceed in this order:

Shape the solid block of Aluminum first. Two sides flat and two round.
Drill the 4 through holes
Cut the space between the cooling fins using the Mill as a vertical lathe.
Drill and bore the cylinder

All advice appreciated!

 

[New_Guy]

it sounds do able but you wont have any support for the end of the job like the tailstock on a lathe maybe try mounting the job on a mandrill fixed in a collet rather than a chuck and just make sure you have enough clearance so you dont run into the table

 

[Philjoe5]

Hi New Guy and welcome to this forum.

I have cut fins in a round aluminum cylinder using a milling machine, a rotary table and a slotting saw. In this photo I have the cylinder mounted on an arbor held in the chuck on the rotary table.

Your cylinder has two sides flat and two rounded so I think this approach would work. If your mill is CNC this would work fine. Manually it took me hours to do but it did teach me to be patient! :

Cheers,
Phil

 

[bearcar1]

Welcome Remout. You mentioned that you are not a machinist in your post, perhaps you could tell us a little bit about what your interests are and how it is that you came to own a CNC mill under the circumstances. What make/model is it? etc. What other type(s) of tooling do you have to go along with your mill? So very many questions we have for you as well, (and you thought this was going to be easy) ;D

BC1
Jim

 

[zeeprogrammer]

Welcome to the forum remount.
There's at least one other member here that's not a machinist (me).
Looking forward to pics of your build.

 

[remout]

Hi Guys and thanks for all the ideas?

I'm a software developer by trade and a tinkerer by passion. Several months ago I got my hands on a Tormach 1100 and I'm having a blast destroying Aluminum. I use a CAD program called BobCad but I intend to start writing my own G code soon.

I know very little about how to operate this mill and even less about machining. It's been quite a learning experience to say the least. I have managed to produce a few usable, but ugly, parts. These engines you guys build are fantastic and I can't wait to build one.

One of my biggest hurdles is just understanding what tool, how it attaches to the mill, and of course what the speed and feed should be. I have the Tormach TTS tooling set and tend to fall back on it as I know what some of the end mills are capable of.

For instance I didn't know what a slotting saw is or how to attach it to the Tormach. I do now It looks like I need a arbor with a R8 shaft (as I have a R8 Collet) and the hole in the saw has to fit the arbor.

I've got much to learn!

 

[Philjoe5]

Remout,
If you have a 1/2" collect you can buy a saw arbor with a 1/2" shaft to fit the collet. Many saw arbors will take a range of center holes in saw blades and in the US, a 1" hole is quite commonly available.

Good success in your machining. I was exactly where you are today in the summer of 2005. I've had quite a fun ride. Keep learning and always play it safe.

Cheers,
Phil

 

[Mainer]

With sufficient ingenuity (and possibly desperation) one can get almost any lash-up to work...and there is nothing wrong with that. We home shop guys routinely do things "the wrong way" because it's the only way we have. So, have at it.

I've heard that for best efficiency, cooling fins should be tapered in thickness and have a significant radius at the base. Whether that is true, or whether somebody was trying to justify the typical form of cast heat fins, I don't know. I notice that computer heatsink manufacturers don't seem to worry about it much.