Lathe Work on Mill

Anyone care to comment on this product?
http://www.milltolathe.com/photo-gallery.php
Possible design flaws, system limitations, or safety issues?
--Lon
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I don't know if I'd cut steel like that. Pushing the spindle over like that. great for graphite, but steel? You'd think it would trash the bearings in a day?
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and the difference in machining steel with a cutter in the spindle is...
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Bang !
--



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bIG DIFFERENCE. Its a single bit tool, lots of pressure. An endmill, little pressure, otherwise it breaks.
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I don't really see any problems with it. It's just as safe as a regular lathe as long as the spindle can securely hold the material. Now I would imagine it would be a bit of a pain to program.
We've done it before to change a tool holder a bit. eg. turn the diameter down a bit for clearance.
But for production, I don't see any advantage.
On 10/2/2009 5:23 AM, Lon Jetivati wrote:

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Forces in turning are a lot higher than with milling. So it will be limeted to small parts and light cuts.
Why not just buy a CNC lathe? You can pick up a five year old 2-axis Japanese lathe for well under 10 grand at auction nowadays. And there's no shortage of auctions.

Limited on length. No possibility of using a tailstock. A cut that would be nothing on a lathe will easily rip the tool holder out of a mill. No single point threading ability, No tool nose radius compensation. No diametrical programming, Strigy chips will just lay on the tools, hell every chip will. Can't run parts from a bar. Can't use a collet chuck.
Should I go on?
How much does this rig cost?
--

Dan


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The chuck and the tool holder block sell for $1148.
The block alone is $799.
No single point threading would be a drawback, that's a mainstay in the lathe department.
But tapping can be done with the mill's tapping cycle.
One design flaw...the cutting pressure on the tools is toward the "mitee-bites" clamping them instead of the solid part of the holder.
CNC lathes usually have some thick safety glass in front and often some steel bars...where most mills have an 1/8 inch of acrylic. Something to consider when this setup spins to 10k rpm.
Lon
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While I'd like to say I would never use a mill as a lathe, I already have done it in a pinch.
I still don't like the idea of turning parts using this method as a matter of course. If you have enough turning work to keep a mill bust doing lathe work you probably ought to buy a lathe,
OTOH, if it's a once in a while thing and everyone uses their head and works safely, then it's OK. The pricing seems reasonable.
I looked at the site again and I see that they do in fact single point a thread using the rigid tap function. I'm not sure every control could do that or even if the threads would come out accurate enough, but it's clever.
--

Dan

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D Murphy wrote:

You must really hate the new Mazak's then Dan.
--
John R. Carroll



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Heh. Kind of a different thing. But I've never had a real high opinion of Mazak.
About a dozen years ago I was at JIMTOF standing in the Mazak booth. No lie, they had a darkened room in there, with a glittering disco ball, and a light show, all to showcase the lathe inside, which was merely a two-axis gang tool that was alleged to be very accurate. But by its construction I knew it could never be.
Then I walked out of the Disco room and was standing in front of this HMC that was blisteringly fast. Super high RPM spindle just going balls out on a big block of aluminum and chattering like a school girl. I suddenly noticed that the great big windows were shaking. They were about 1/32" thick acrylic. They would barely stop a flying chip, never mind a face mill launched at 20,000 rpm.
I backed away and looked around. It was all so cheesy. Then it hit me. This was Japan's equivelent of Haas. A decade and a half ahead of Haas maybe, but the same damn thing. Cheap and cheesy.
--

Dan

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I've done this in B'-ports 25yrs ago, in a pinch. It works great for "certain" types of jobs. Light cuts, with custom bored spindle collet ie(R8 soft blank) /holder/chuck jaws- to hold work pc, ect. Whats really neat on a CNC, A precision arbor for 7-8" surface grinder wheels. Mount a clear-view dresser in the vise for wheel shape. I did this for CNC grinding graphite trodes for automotive (Cadillac interior) lens bezels molds(v-groove on large rad. X-Y steping up another rad. in Z- kinda bowling ballish. Don't try this a home!<g> If ya do, cover your machine with ? so grinding grit do'nt get were it aint sposto.- same as when toolpost grinding on the lathe. I gathered up used shop aprons for cover/protection. Moldmaker story: certain types/brands of surface grinding wheels perform very well in graphite. They dont load-usually a major freekin squelling problem in graphite,retain their shape fine detail not always achivable with an endmill due to 0 cutting surface speed at the bottom of V grooves for examlple. The harder 150g+ "open pore" wheels soft bond G are the ticket for trode work.IIRC we used a 200g "por0sway". Tip: these wheels need to be rough dressed 1st with "standard" marble diamond, then finish dress with a SHARP phono point.
So WTF? If ya can't say it here where the hell can ya?<g>
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cncmillgil wrote:

Gil:
    That reminds me of something I had never heard of being done before, but thought I'd give it a try.
This was back around '79 or '80 and on a Bridgeport Boss I CNC. I tried grinding (with a surface grinding wheel in a special holder I made to fit the CNC) some mold ejector pins at an angle to the axis of the pin. The grinding wheel would come and contact the pin and circle around & around the pin until the pin was to size and go home. The ejector pins ended up with boss on the end that was at an angle. Actually it worked pretty good. That is, until one time something happened in the program (I don't remember now just what - maybe a mid-program start that lost some parameters) and the grinding wheel tried to go sideways right THROUGH the pin and cracked the grinding wheel which then broke and tried to throw a chunk of grinding wheel, the size of about 1/3 of the grinding wheel, right through my chest at 3600 rpm! No sheet metal enclosure on this mill. I stood there just stunned holding may hand to my chest on top of the chunk of grinding wheel. Man, my chest was black and blue for weeks.     To use your phrase, now that's REALLY something you don't want to try at home. :)
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BB: Yup been there done that, mine was on a B-port, damn moldbase plate(2 cav Norelco Dial-A-Brew strainer basket-floating B plate that slides rode on - actuated by cam rollers outside in tracks- very cool design- no angle pins! , decided to contunie rotating - after the bolt sticking thru the LP hole fell out - directly into my chest.:-( the other downhill snow skiing. Black & then every color under the sun as it healed. We had a Gorton MicroMaster? mill we did grinding on- with a cross- slide turntable. It had a precision 6K spindle- Light touchup only- Lots O 1/4" Plexiglass sheilds- couldnt see thru'm from burnt chips, but will save your life!
Have an average Day!
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Why can't you use the rigid tapping cycle for single point work? OK, it will drag a bit on retract...
But there is also IPR mode with an M29 (?)
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Yeah. I don't want to be anywhere near when the pull stud breaks.
Later,
Charlie
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