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View Full Version : Any lathe tool changer plans around?



kong
05-02-2005, 03:30 PM
Like it says!
I have always liked the thought of having an auto-changer on the lathe, even if it a manual one (chair) You know what I mean! So, has anyone made a tool turret, or know of any plans available to build one?

nervis1
05-02-2005, 04:32 PM
HSM has had plans for a tailstock turret in the past...maybe twoyears I think. If you give them a call or visit their website, look through their index you can find it I'm sure.

JFettig
05-02-2005, 06:30 PM
I saw someone on a mini-lathe yahoo group with a horisontal like turret. If I had the cash laying around, I would take a cheap rotary table, make a plate to mount tools to it and use that as a tool changer, with a home switch to home it out every time, it would work perfectly.

Jon

Mcgyver
05-03-2005, 07:02 AM
the radial positioning would be ok, but in my experience, the trick that costs all the money is the ability to hold the cartridge very solidly with a quarter turn of a lever. you can spend 1k just on the turret. i know there have been dyi projects on this, will try to remember where i've seen them

kong
05-03-2005, 07:10 AM
I think you hit the nail on the head there - I see the industrial turrets use "hirth couplings" or face gears for rigidity. These will certainly be difficult to compete with for the serious hobbiest.
I have just dismantled my capstan head to look for the mechanism. It has a sort of raised ring on the plate, and a corresponding sunken ring on the toolholding plate. This way they interlock and provide a rigid platform to stop any lateral movement.
The problem is locking and unlocking effectively. A single pin inserted into the rear of the faceplate would be a start, but eight pins would be more rigid. How wouod you go about pulling out all eight pins at once though?!
I will keep scouring the net looking for ideas!

MIKE JEFFERS
05-03-2005, 07:28 AM
kong
i think this lot do or are going to do a tool changer (4 internal / 4 external tools)
but i dont see it on their site
http://www.emcomachinetools.co.uk/temp.htm
mike

kong
05-03-2005, 07:33 AM
Tool changer is what I{ am looking for, can't find it on the site though :(

kong
05-03-2005, 07:53 AM
Here's an interesting page - http://www.doriantool.com/Turrets/acc_s3.pdf
I see the head spline is lifted via the angled grooves in it's body, then it is rotated and drops back into position, again via the angled grooves. Quite simple, but how is it locked back against the body spline once it has finnished rotating? Hmmm, I dunno!

JFettig
05-03-2005, 08:19 AM
Kong, we have about 3 or 4 of those dorian tool turrets at work, they work really well. they will hold up to 8 tools and do it well.

What I am dreaming up is using a rotary table with a wormgear, so there wouldnt even be a possibility of it turning back.

Jon

kong
05-03-2005, 08:21 AM
Jon, I see where you are coming from, and have contemplated the same thing. What worries me is the backlash in the gear. This will lead to movement, albeit very slight.
So, couple your idea with a decent locking device, and we have a plan!

ozzie34231
05-03-2005, 08:39 AM
There are plans for a turret changer on the Mach discussion group site, files section. It uses a combination of compressed air and a stepper motor ,sequenced by a macro I think. The head is held in position by eight precision placed pins. The file contains both text and drawings.

Jerry

Mcgyver
05-03-2005, 08:53 AM
kong, i guess it depends a little on your use - if you are setting up production or looking for a turret lathe type set up that’s one thing, but in a manual situation the value comes from 1) the speed of the tool change 2) that the tool is preset in the cartridge at centre height and 3) the general rigidity of the set up. Whats the trade off? $$$$ and rigidity - even the best are less rigid than a blocked set up on the compound and the oldtimers will tell you to lose the QCTP for heavy, demanding jobs.

After having used a very expensive quick change tool post (http://www.drehblitz.com/) with accurate indexing for many years (in a non production environment), I can tell you it is an amazing addition to the shop but the index-ability is of negligible value. Most of the time I make an analogue adjustment (loosed the bolt holding to the top slide and put the darn thing where I want it).

Therefore, if you study the Drehblitz site and discard the need for indexing you can replace the spline piece with a cylinder. That moves squarely into what we can make at home – it’s basically a cam-lock system. I can take some close up shots if it would help.

Mine came with the lathe but with only 1 cartridge. Fortunately, I didn’t have to make the turret but I’ve made a dozen cartridges. They are not hardened and ground but are more than adequate and I’ll never wear them out.

I’d recommend against using a rotary table as it does not address points 1 & 2 above and impairs 3, (all just imo, each builder has their own objectives). Radial motion of the tool is, imo, only necessary or desirable for radius turning. When this need arises there are easier ways to deal with it.

JFettig
05-03-2005, 09:16 AM
Mcgyver, I think in a way your misunderstanding where I am going with this, the rotary table would be in verticle position for one, I got my rotary table spinning over 10rpm(thats only at 25000hz) and it 'seems' rigid, but I have yet to try it.

I belive that the enco compact lathes use a rotary table type thing with a locking pin(not totally sure on the locking pin)

Heres the service manual I picked up somewhere(not sure, maybe mach2 group or mini lathe group)

Jon

Mcgyver
05-03-2005, 09:27 AM
ahhh, you are right i was thinking something completely different. I took turret to mean the turret in a quick change tool post.

funny how a little thing like what plane we're talking about can send a guy completely down the wrong path :)

kong
05-03-2005, 09:31 AM
Ozzie, you beauty!
I have traced the files on the site back to this website with pictures and movies!

http://www.issintl-inc.com/latheturret/

This one seems like a keeper to me. I am off to do some more reading on it.
Thanks!

MIKE JEFFERS
05-03-2005, 10:04 AM
i also have a dorian tool changer nice bit of kit
the locking mech is a pneumatic wedge ( imagine a gear wheel and using a key to lock it in position)
mike

Chris D
05-03-2005, 01:31 PM
Hello,

Someone posted an exploded view of the Emco Maier turret. This turret works okay, but you need to be aware of it's primary weakness if you exploit the design.

You will see a thin metal strip that goes under the center shaft, this device works like a ratchet and pawl and serves the purpose of a "shot pin" to lock the turret in position. The worm gear rotates the turret past the drop in point, then backs up against the metal strip to lock it.

This metal strip will bend and flex under moderate loads allowing the turret to rotate (tool goes down below center). If you do anything with the design, this is the area that needs some serious attention - beef it up in some fashion to prevent this problem.

Other than that, the turret performs pretty good. We had three lathes in a CNC training lab that saw constant use over a 5 year period. Other than that problem, it works well. We could not cut steel on the machines with any reliability, however, aluminum and other light allows worked well.

Chris

MIKE JEFFERS
05-04-2005, 02:31 AM
kong
"We have an ATC for our own CNC Lathes. They are only designed for use with our MillPlus or CNC software and controllers. It has 8stations(4 internal and 4 external) price is £1000.00.
Regards
Bryan Tate"
e-mail from promachine tools
should be do'able for less than a grand ( and then some)
mike