[oknups]

I am going to buy a Tormach sometime before summer, not sure which yet.

Most of my work is going to be small parts for bicycles, in AL, and TI. But there are some large molds that I want to machine as well. Probably in AL jig plate. I have made smaller molds in UHMW polyethylene. Its very good material for doing composite work.

Size of the part is an issue, but it could be machined as smaller sections and joined. Slide is of a prototype rear end mold, bottom half. Not shown are bolt holes, or resin channels. The mold has to withstand internal pressure in the 150 lb+, but below 200 psi. UHMW is out for heat cure carbon fiber fabric, but I could continue to use wet layups, and no heat cure.

Opinions please, which one, keep in mind I will want to use the machine to mill UHMW molds that are smaller than the one shown. 770, or the 1100?
[IMG] btm mld by oknups, on Flickr[/IMG]

[dbrija]

Do you have any restrictions such as floorspace, etc..?

If not, I would recommend getting the 1100 just for the larger work envelope, HP, rigidity, etc...

You can take the spindle speed difference out of the equation for the most part by using the speeder, which would give you a 15k spindle if that is a decision factor.

The machine needs 220V, but this should not be a major concern. I wired in my own in my garage. Relatively cheap to have done professionally.

[oknups]

Do you have any restrictions such as floorspace, etc..?

If not, I would recommend getting the 1100 just for the larger work envelope, HP, rigidity, etc...

You can take the spindle speed difference out of the equation for the most part by using the speeder, which would give you a 15k spindle if that is a decision factor.

The machine needs 220V, but this should not be a major concern. I wired in my own in my garage. Relatively cheap to have done professionally.

No space issues, or power issues.

Leaning towards the 1100, but I like the higher spindle speed and feed rates of the 770. The mold parts are very large files, machine run times between the two at max feed rate become significant. If my math is correct a finish pass, will take 10 hrs on the 770, 14 hrs on the 1100. Probably the low side for time. Estimates based on (width of part x length x 1/step) / xy feed rate IPM. Ignored z axis time.

This guesstimate is on par with machine time on a large router using similar feed rates. Step size was much larger, and I interpolated the math.

[Magnum164]

Just out of curiosity since I don't think I see it, what is the height of that part? about 3-4 inches?

[Tormachmaster]

Go with the 1100 for those bike parts. I do alot of work for a guy that builds custom bikes you will want the larger mill.

[oknups]

Just out of curiosity since I don't think I see it, what is the height of that part? about 3-4 inches?

Just under 3", Plate needed is 2". Preliminary drawing.

[oknups]

Go with the 1100 for those bike parts. I do alot of work for a guy that builds custom bikes you will want the larger mill.

Thanks, I sort of decided the 1100 was the way to go. Lots more options for it over the 770.

Might I ask what kind of work?

Down the road I would like to machine stems, and brakes.

[tikka308]

The 770 is great if you absolutely need the 10K spindle, but the price is close to the 1100 - and for the 1100, you get significantly more travel and horsepower. I also use the power draw bar on my 1100 (not currently available for 770) - that alone would "make" the decision for me.

[Don Clement]

I also use the power draw bar on my 1100 (not currently available for 770) - that alone would "make" the decision for me.

I agree. The Tormach 1100 is a different (much better) machine with the Power Draw Bar. The option of the PDB would be the deal breaker for me.

Don

[Magnum164]

I am at work but you might want to look at the width. That 8.6" is getting close to the max width of the 770 I believe. You would have to rotate if you have any wider than that.