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Tormach microArc 4th axis any good?

rk9268vc

Aluminum
Joined
Dec 2, 2021
Location
Minnesota
Im looking to get a 4th axis for my mill

Im not really looking for simultaneous, more so 3 + 1 so I can do 4 sides of a part in one setup
I do a lot of parts with holes and features on all 6 sides, so instead of 6 setups, it would be nice to do the bulk of it with a 4th axis

I am liking this particular 4th axis because it has a harmonic drive instead of worm and wheel. Since I need to hold parallelism between opposite sides, I need it to hold pretty rigid when milling

How well does Fusion handle 3 + 1?

Anyone have experience with this 4th axis? Thanks

here is link
microARC 4 4th Axis

Yes I KNOW Tormach isnt one of the best brands, save your breath, I am just goofing around in my garage turning aluminum and plastic into 100 dollar bills. I would have a bigger mill if I had the space.
 
Harmonic drives are neat, but a rotary axis still needs a brake or curvic. I guess maybe not in Tormach land with .01 DOC roughing passes?
 
Harmonic drives are neat, but a rotary axis still needs a brake or curvic. I guess maybe not in Tormach land with .01 DOC roughing passes?

Adding a teknic inline brake wouldnt be a bad idea

No, I run my mill pretty hard. For example, with the shear hog I get around 5 cubic inches/min MRR in 6061
 
The first thing I noticed is that from the picture, there is no way to indicate the 3 jaw chuck in. So runout would be an issue if you're holding onto parts with a finished O.D.
 
The first thing I noticed is that from the picture, there is no way to indicate the 3 jaw chuck in. So runout would be an issue if you're holding onto parts with a finished O.D.

Sorry forgot to mention, I would be mounting a small self-centering vise to the faceplate like you would see on a 5 axis mill
All my parts are rectangular-ish
Probably going to be grabbing them with small dovetails, then 2nd OP would be in a standard vise to whip off where it is held, or just part it off.
 
.......I am liking this particular 4th axis because it has a harmonic drive instead of worm and wheel. ......

Harmonic drives are interesting, but my experience with them in machine tool application has been disappointing. Tsugami used to use a harmonic drive to index the turret on their Mercury line of lathes. The flexing cup portion of the drive would develop cracks, sometimes in as little as 2 years use. May have been a sizing issue, but who knows?
 
Harmonic drives are interesting, but my experience with them in machine tool application has been disappointing. Tsugami used to use a harmonic drive to index the turret on their Mercury line of lathes. The flexing cup portion of the drive would develop cracks, sometimes in as little as 2 years use. May have been a sizing issue, but who knows?

I called Tormach on this, they said they havent had any issues with the drive. They have a 1yr mfg warranty, but said that if there was a defect they would work with you. Tormach isnt known for outstanding customer support though

I asked how the stepper was mounted, as they dont have pictures or anything, to see if I could fit an inline brake on it. They said it would void warranty to do anything to the assembly (thats dumb but whatever). I may even consider putting a Teknic servo in it instead of a stepper, because steppers are dumb

I also asked for dimensions on the faceplate to see if I can find a 4 jaw chuck or other mounting stuff for it, but they said they will get back to me on it
 
For future reference, here are the dimensions of the face of the 4th axis

"The microarc has 3 M6 mounting holes spaced 120 deg apart on an 85mm PCD. "

5e934f18-f980-4cc4-98e6-8357ca693f7a.jpg
 
Sounds like a real stout unit with a fastening foundation like that to build on.

Does Tormach offer it in any colors like hot pink or fuchsia?

I intend to void the warranty immediately by adding an inline brake on the motor, so ABSOLUTLY I need to paint it

How about a speed stripe while im at it?
thats got to add at least 20% more performance.

do you think a flame decal would be pushing it?
 
I'm not too comfortable with even a small RT like that using an aluminum housing. But with light-enough cuts I'd guess it could work. Is it going on a Tormach, or into another make?
 
I'm not too comfortable with even a small RT like that using an aluminum housing. But with light-enough cuts I'd guess it could work. Is it going on a Tormach, or into another make?

Im not too sure on the aluminum body thing. It says that, but then it looks like it has a casted body in the photo. I'll give them a call on it tomorrow.

It is going on a tormach sized mill for aluminum work. It is the same size as their 1100MX, mine actually uses bigger teknic servos and ball-screws.
Its got 24in, 11in, 15.5in x,y,z travels, 400in/min all axis, 2HP spindle
Still hobby range for sure.
It has made me enough money to justify putting a little more upgrades into it though. The mill paid for itself in like 2 weeks of small jobs.

I have dreams of a bigger mill, and keep seeing ones go in auctions for cheap, but I dont have the space for one in this house.
 
I intend to void the warranty immediately by adding an inline brake on the motor, so ABSOLUTLY I need to paint it

How about a speed stripe while im at it?
thats got to add at least 20% more performance.

do you think a flame decal would be pushing it?

Paint it red to make it faster, or blue to make you luckier while using it. Purple if you intend to be clever or sneaky. At least that's what da orks do.
 
the product desc says it is made out of aluminum, but the picture makes it look like the cream colored part of the body is made out of cast iron. is this true?


Today 9:03 AM
rk9268vc,

The main housing is aluminum, yes. The cover over the motor is sheet steel.

Thank you,

Norman
 
the product desc says it is made out of aluminum, but the picture makes it look like the cream colored part of the body is made out of cast iron. is this true?


Today 9:03 AM
rk9268vc,

The main housing is aluminum, yes. The cover over the motor is sheet steel.

Thank you,

Norman

Now you have to decide whether it'll hold up under the work you want to do. If light cutting it might be fine, just use heavy, thick washers for securing the RT to the machine table to prevent "smushing" the Al from the bolt head load.
 
Now you have to decide whether it'll hold up under the work you want to do. If light cutting it might be fine, just use heavy, thick washers for securing the RT to the machine table to prevent "smushing" the Al from the bolt head load.

im more and more leaning toward just getting their normal worm drive 4th axis. Watching videos this thing is just tiny

Their 6" 4th axis "super spacer" seems to be a lot more robust and has 2 more inches of table diameter
33089 - 6 in. Super Spacer Motorized Rotary Table

119lbs of casting vs 38lbs aluminum for example

The stepper is in the wide open too, so can easily be replaced with a servo with brake.

it has a bigger thru-bore as well, but i think i will lose a bit more bed space with it

going to have to do some more research.
 
im more and more leaning toward just getting their normal worm drive 4th axis. Watching videos this thing is just tiny

Their 6" 4th axis "super spacer" seems to be a lot more robust and has 2 more inches of table diameter
33089 - 6 in. Super Spacer Motorized Rotary Table

119lbs of casting vs 38lbs aluminum for example

The stepper is in the wide open too, so can easily be replaced with a servo with brake.

it has a bigger thru-bore as well, but i think i will lose a bit more bed space with it

going to have to do some more research.

A CNC 4th has a hydraulic or air brake as part of the main spindle. That way cutting forces don't beat the gears to death and it will hold position.

That manual indexer with a stepper mounted scabbed onto it still has the manual spindle lock lever. That is how you would need to use it.

A servo doesn't need a brake unless gravity moves the axis when the power is off.
 
Please ..

Look at the specs and weights and torsional rigidity of a HAAS rotary table.

Approx 100x-1000x more rigidity.
Anything with a 85 mm PCD for mounting holes, of 6 mm, is a joke.

140 mm pcd x 4 x 8 mm shcs would be a good minimum start.
About 20x better (pwr 3 d iirc).
 








 
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