Proxxon PD230 metal lathe and CNC kit short review

[robbl]

Having cleared the cupboards of some my old unmade plastic models and generated some spare cash, I finally splashed out and got a metal lathe, so I thought I might make a couple of notes about it. I am a lathe novice, so if I get terminology wrong, I apologise.

 

My requirements included:

• Light weight so it can be stored in a cupboard or moved outside for use
• Able to turn 45 mm diametre (I hope to make a 1/24 scale cannon and a carronade)
• Able to use a variety of tools
• Able to take a CNC kit to repeat jobs accurately and to cope with tapers and curvey bits

Locally in NZ, the Sieg machines and a lot of clones are available. They are cheap but quite heavy at between 35 and 55kg for the small ones. So in the end I chose a Proxxon PD230 which weighs in at 10kg with its clothes off, can turn up to 56mm, can use small lathe tools (up to 8x10mm tools) and has various CNC kits available on the market.

 

 

Technical specifications:

• centre distance: 230mm
• swing: 52mm
• height over cross slide: 28mm
• cross-slide travel: 60mm
• top slide travel: 45mm
• steel toolholder: accepts 8mm x 8mm cutters
• spindle bore: 10.5mm
• thread cutting capability: 0.5mm, 0.645mm, 0.7mm, 0.75mm, 0.8mm, 1.0mm, 1.25mm, 1.5mm
• spindle speeds with reduction: 3,000rpm, 900rpm, 300rpm
• automatic feed resolution: 0.05mm/rev or 1.0mm/rev
• tailstock spindle: MK1 bore (short)
• tailstock travel: 30mm
• internal chucking capacity: 2mm - 35mm
• external chucking capacity: 24mm - 68mm
• handwheel resolution: 1 revolution = 1mm feed (40 divisions)
• mass: 10kg
• dimensions: 530mm x 250mm x 150mm

 

The lathe came with 3 jaw chuck and live centre and a few bits and bobs for threading and gear cutting, which I do not plan on using.

 

In addition, I got (over the following couple of weeks)

• splash guard/tray
• Quick tool change post plus extra tool holders
• Proxxon's HSS tool set (5 tools)
• Fixed steady
• Boring tool set
• Tail stock drill
• Tool holder for rotary tools (Dremel etc)
• Set of 7 indexed tungsten carbide tipped tools (on special from sieg shop here)
  The 8mm high x 10mm wide tools fit in the tool holders made for the quick change tool post.

Out of the box, the PD230 is almost ready to fire up after a quick check on the various fittings. It runs surprisingly quietly, and is very compact (in fact the lathe could sit inside my HMS Blanche).

 

I got some Acetal (Derlin) rod for practising on and created a bit of a mess which pleased me no end. With the tools all adjusted for height and distance from the centreline, it is very easy to swap tools around in the middle of a job. I got used to facing and general turning (the lathe has an automatic feed if required) but the one task I am struggling with is parting and deep grooves. At the moment I am avoiding both tasks by using a saw.

 

The CNC kit came from Ideegeniali.it, and it arrived shortly after the lathe did. They claim it only takes 5 minutes to assemble, but it took me about 10 minutes ... but who's quibbling. Wiring it up wasn't difficult either, and then it was time to consider the control software.

 

I chose Mach3, which requires a PC with an printer port. That took a bit of finding, but after a bit I had everything hooked up and ready to go. Ideegenialli supply configuration files for Mach3, so apart from a couple of minor tweaks the computer soon had control over the lathe, with the ability to make moves in the X and Z axis rapidly or jog tiny distances. With the kit in place, I can still manually work the lathe, although I need to remount the original hand wheels onto the stepper motors to make that easier.

 

I already have a CAD/CAM program, so the next step was to create something. I worked up a drawing of a carronade and a cannon from Wayne Kempson's plans in Allan Yedlinski and his book Euryalus V2 and started testing. The testing taught me a few things about tool selection and pathing, as well as how to cope with the complex shapes, such as the breeches of the cannons and carronades. Under CNC control, the carronade can be turned in one job (several passes) with a single tool, while I am turning the cannon first from the barrel back with one tool, then flipping it in the chuck and turning the breech end using two tools (here the quick change post comes into play). I still do facing, drilling and parting off manually.

 

 

The jobs are not perfect yet, as I have a couple of issues to work out:

1. When I flip the cannon to turn the breech end, the chuck marks the barrel. I am contemplating leaving a V groove oversized in the barrel to slot the chuck into the barrel, then manually turning that out at the end of the job.
2. The finish is not as good as I would like, which I think is a result of tool choice. When turning from the left or right, it is really nice, but the 55 degree straight tip is leaving grooves. Multiple finishing passes clean these up, but a better tip might be a plan.
3. Parting ... if I can't do something manually, then there is no way I'm going to do it under CNC control. I think I have the height correct (on or slightly higher than centre) and am feeding slowly, but it just doesn't work well for me. This may be due to the plastic bending away from the tip, then trapping the tool as it flexes - brass may be better. Or I am parting to far away from the chuck, or with the part still under pressure from the tail stock it is trapping the tip.

 

Conclusions:

Pros:

The lathe is more expensive than others, but meets my requirements for space and capabilities.

Accuracy of the lathe is impressive, but I can't compare to other brands.

The CNC kit works well and lets me do things I think I would struggle with (complex curves and repeat jobs)

Both the lathe and the CNC kit worked straight out of the box.

I spent (and still spend) a lot of time looking for hints and tips on turning - that is time well spent.

 

Con:

The operator is a bit inexperienced and could do with a bit of learning.

 

Overall, a nice machine to have and I am glad I finally took the plunge.

 

Cheers
Rob

 

PS: some wood turned - old walnut dowel from an old damaged kit.

 

Edited March 8, 2014 by robbl

[robbl]

Hi Brian, sorry should have added the specs.

Centre distance: 230mm

 

Editing the first post to add tech specs and a couple of photos of wood turning.

 

Cheers

Rob

[Keith_W]

Thanks for posting the review, Rob. I was considering a PD230/E myself, but in the end I sprung for a Sherline.

[robbl]

And this year's "Cannon Award" goes to ......

 

 

Getting better but a couple of fixes to make yet. Finish was ruined because, as I found out, turning the thin area behind the breech causes the rest of the barrel between that and the tail stock to move slightly .... tarnation! I will have to make that step happen after the fine finishing turn of the barrel.

 

To give an idea of accuracy, I had the lathe turn a length of brass down to 0.2mm. The rod connecting the barrel to the pedestal in the attached picture is .9mm

 

Cheers

Rob

 

[dgbot]

When turning acrylic or plastic your tools must be very sharp.  Acrylic is very flexible.  After turning the outside of the barrel drill out the bore.  When you turn it around to do the orher side put a dowel in the bore and chuck the dowel in the lathe.  This way you will not damage the barrel.

David B

[robbl]

Ah ha! Thank you David, that helps a lot.

 

Cheers

Rob

[dgbot]

That is what we are here for.  I am looking forward to our build,

David B

[Q A's Revenge]

Nice review, should be very useful for folks contemplating buying this lathe. Looks like a very nice machine.

 

Getting marks on work from chuck jaws is a common enough problem for folks. Two immediate remedies spring to mind, either place suitable packing between the jaws and the work. I've used pieces of aluminium drinks cans and card to good effect. Or if funds allow consider using a collet chuck, these are much kinder to the work piece!

[Jeffrey Wagner]

When using a part off tool make certain it is absolutley square to the work axis. Set the heigth a few thou lower than center, it will leave a tiny nub but it will cut easier. Also LOW RPM when parting. And do not ever use a tailstock when trying to part off a tool. As for finish, find a tool with a nice small nose radius and watch your feedrate. You should know what it is in inches per revolution and play with it a bit to get the best finish. And remember RIGIDITY is king. The stiffer and more solid your setup the better, Have any direct questions ask away. I have 30 years machine shop experience.

 

Jeff

[wefalck]

Collets increase the precision when re-chucking and also are much safer to work with than 3-jaw-chucks.

 

Not sure, where the repeatedly given advice comes from, not to use a tail-stock during parting off. It will be impossible to cleanly part off longer pieces (say more than 4 times the diameter) without support, as any imbalance will make the part wag like a dog's tail, once you get down to say 1/10 or less of the original diameter.

 

Another thing modern mechanics (and instructors) seem to frown upon is using a hacksaw or a jeweller's saw for parting-off. Our model-engineering or watchmaking lathes are not rigid enough for more serious parting off jobs. On larger lathes this is done with an tool upside down in a rear toolpost, but the smaller ME lathes are not normally equipped for this. Old-time mechanics 'vademecums' suggested to start the parting cut with a grooving tool and to finish the cut with a hand-saw. This is what I have been doing for 30+ years. Saves you a lot of hazzle and material(!). This is another reason, why I prefer collets over chucks - no risk to get caught in the jaws. When sawing or filing (another old-time practice, now discouraged in textbooks) with the lathe running, make sure that your body and face is not in line with the saw, so that in the event of a kick-back it does not hit you !

 

Re-chucking a piece with a wooden dowel in order finish off the other end of the piece is likely to cause re-centering problems. It may be ok for filing, but almost certainly does not work for turning, let alone CNC operations.

 

It might be easier for CNC operations to turn a gun in two parts and solder the pieces together.

[bruce d]

2 hours ago, greenie said:

Got a question for Jeffery Wagner, you state -------  do not ever use a tailstock when trying to part off a tool ----  WHY is that ?

I'll jump in here. When you part off, the piece that is 'parted' must move. One way or another, it is now loose and it may well have started to move just before the parting was complete. If the parted piece is held in place by the tailstock you are going to trap the parting tool between the two pieces, one of which is likely to become shrapnel.

 

Hope this helps.

Bruce

[Bob Cleek]

9 hours ago, wefalck said:

When sawing or filing (another old-time practice, now discouraged in textbooks) with the lathe running, make sure that your body and face is not in line with the saw, so that in the event of a kick-back it does not hit you !

Definitely! Staying out of the "line of fire" is good advice for any lathe or table saw operation.

 

I would also add that any filing done on a running lathe should be done with the handle of the file in the operator's left hand with their right hand controlling the tip of the file. This practice, for a right-handed mechanic, is the opposite of other filing operations when the workpiece is held still, as in a vise. The reason for this practice when filing on a piece held in a spinning lathe is that the mechanic's left hand, forearm, or elbow, is not adjacent to the spinning chuck when filing. 

 

It can't be mentioned too often that the lathe, while the most useful and versatile of all machine tools, is also the most dangerous of all machine tools. Some might believe the table saw to hold this dubious distinction, but that is not so. The table saw may account for the greater number of injuries, but that is only so because there are more table saws and they are more accessible to the unwary and untrained. The lathe, however, is a vicious and merciless adversary which, when it grabs, does not let go. The danger is perhaps less with the tiny mini-lathes than with the large industrial machines, but the capacity to maim is present with all of them. In many shops, operating a lathe alone is prohibited. Someone else should be present in case something goes wrong. About ten years ago, a young woman undergraduate at Yale, operating a lathe alone in the chemistry department machine shop, was killed when the lathe caught her long hair and pulled her head into the spinning chuck.  https://www.nytimes.com/2011/04/14/nyregion/yale-student-dies-in-machine-shop-accident.html She failed to heed the basic safety rules for lathe operation: no jewelry, no long hair hanging loose, no loose clothing or long sleeves, no gloves when operating a lathe. Stay safe out there! 

Edited February 19, 2020 by Bob Cleek

[wefalck]

I have seen this 'do not part off with the tailstock supporting the free-end' in various textbooks, but never understood why ...

[bruce d]

23 minutes ago, greenie said:

Maybe you should try it, before becoming an expert on this subject.

?

I have 'tried it'. My comments are based on personal and professional experience. CNC procedures are totally at odds with those of a hobbyist with a small manual lathe performing parting off with a hand feed. And yes, I did support workpieces when maching cast iron bar on my large lathes but the more useful information in context here is directed to hobbyist users machining small workpieces on small lathes.