advice on which 45 clone

[defed]

looking to get my 1st mill. it will be a hobby machine, probably won't ever CNC, but i don't know where else to ask for advice.

i started looking at smaller models, but i keep saying "for a little more $ i can add this, for a little more i can add that" so....

right now, i'm looking at the grizzly g0755, g0761 and pm932 (possibly g0762). i just don't know what is important as far as features go. power x feed seems like it would be useful, but is a motorized headstock? is it meant to be used for boring while down feeding? from the literature, it said lock the headstock before using, so that seems to contradict the uses of powered headstock. some come w/ this feature, some come w/ that...it's confusing! i'd like 3 axis DRO, but i think i can add it somewhat inexpensively in the future. the 762 has VFD, i believe i can upgrade that later too.

i think i like the base that comes w/ the 755 and 932, as it appears to be heavier than separately sold bases.

i'm sure i can find a used bridgeport for less, but i think the 45 will offer me the best compromise on power/weight/cost/space.

thanks for any advice you guys can offer!

Dave

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[109jb]

The motor for head lift is just so your arm doesn't get sore cranking the heavy head up and down. It is not meant for fine feeding like boring. When not CNC'd the head should be locked as the screw likely has a good amount of backlash that could show up in the finish.When CNC'd, attention is payed to eliminating backlash, and to the dovetail slides. This is why a CNC'd machine doesn't need the head locked.

As for the 3 Grizzly choices, all are about the same physically but a few notes.All are about the same physically, but the 0755 head will tilt 90 degrees left, whereas the other two will only tilt 45 degrees either way. The 0761 doesn't have the x axis power feed and is a single phase motor. To me the extra $500 for the power feed, and VFD motor with the higher speed spindle on the 0762 is worth it for a manual machine. I happened to visit Grizzly while on vacation a few weeks ago and the G0762 really caught my eye. If I am remembering right it had a Hitachi VFD. If it were me I would get the 0762 out of those 3 choices.

[countryguy]

What materials will you plan on running thru? Alum, plastics etc. any steel and/or alloys. Since you have a 45 in mind, Check out Precision Matthews Milling Machines known for quality, support, and service of his goods. Everyone on my forum loves them. Many are now moving up to the 9xx stuff he is bringing in. Best, CG.

[defed]

What materials will you plan on running thru? Alum, plastics etc. any steel and/or alloys. Since you have a 45 in mind, Check out Precision Matthews Milling Machines known for quality, support, and service of his goods. Everyone on my forum loves them. Many are now moving up to the 9xx stuff he is bringing in. Best, CG.

which forum are you referring to? i'd like to check it out.

the pm-932 is also on my list. i am sort of leaning towards it because it seems to have the most options/configurations available, but now that i think about it, i may or may not ever want or use some.

will i ever need power quill down? probably not. motorized head seems more useful at this point as you are always moving the head. for $300 extra, i can get the 932 w/ powered quill and a basic Z-DRO added to the 755. could i add a quill down motor for that? after reading, it seems one could add the VFD (minus a compatible motor) for a couple hundred. not sure if the spindles are all the same between VFD and standard models.

i plan to run just about anything through it, plastic, alum, steel....i'm in no particular hurry, and a 45 has to be better than my dad's old single speed, belt driven, knee mill and he does steels (although slowly as well).

[arizonavideo]

" dad's old single speed, belt driven, knee mill "

That might be harder then you think.

What does he have?

[hanermo]

Basically, rigidity wins.
Mass wins.
Buy the heaviest per work cube - all else is incidental and peanuts in costs, later.

Note doubling any one axis re: free length, You need 8x the mass for same rigidity.
Rigidity is cube, ie power of three, of free length n, on every axis.

In practice, heavier mass absorbs vibrations better => better output.

Example:
Most grizzly stuff is really, really lightweight.
So, their 12x lathes (24-30") might be about == 200-250 kg in mass.
My 12x24" lathe is 450 kg.

Compared to a grizzly 12x30, my lathe is about 8x more rigid.

On std mills, the column section size / mass is everything.
It is usually never specced.

So, a column ie the z axis, of say 120x120 mm, vs say 200x200, the bigger one is about 7-10x more rigid.
Skins or thickness, usually about 10 mm, but the section size is vastly more important.

Fwiw..
I am now using 20-30 mm thicknesses, in tool steel, and 240-300 mm box frames.
Similar in 10 mm cast iron do 5-7-25 kW industrial-tool outputs at spindle.

[dracozny]

If I were to do it all over again and I had the room, I would build a Granite machine. That said if you are dead set on a 45 clone, then get a Precision Mathews, they are one of the better machines in that class. I have a ZX45 that I was spending a considerable amount of time converting to CNC, It's a horribly sloppy machine and even the bolt hole patterns aren't even square.

[MonoNeuron]

How did you get on Dfed?
What did you end up with and how is it working out for you?
I hope you got the one with a power feed option as you get sick of cranking pretty quickly on some long jobs.
Rich.