Any lathe tool changer plans around?

[kong]

Like it says!
I have always liked the thought of having an auto-changer on the lathe, even if it a manual one You know what I mean! So, has anyone made a tool turret, or know of any plans available to build one?

[nervis1]

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]

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]

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]

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]

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]

Tool changer is what I{ am looking for, can't find it on the site though

[kong]

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]

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]

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]

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]

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.