What about a tapemate?

strantor

strantor

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I've wanted a CNC mill for years but can't afford. I like things like the proto-trak bridgeport and the PM45-CNC. Watched all kinds of videos and forum threads on CNC-izing manual mills. I think it would be easier to buy an older actual CNC machine and retrofit the controls, but the problem there is those machines are usually huge.

I came across a Pratt & Whitney Tapemate Series D (circa 1985) here locally and I'm going to go have a look at it tomorrow. I've never heard of one, but it seems not much bigger than a bridgeport, and seems to be in good shape and running with the original controls. I did a bit of research on it and found some people saying it's a glorified drill press and not cut out for milling - those comments came from a less-hobby-oriented site (I think you know the one - Practical M.). Other people said it works fine for milling. There's a video of an already retrofitted one milling, here:


Do you think it's worth investing in? How much would you offer for it, assuming it's in good shape (asking price is $4800)? What should I look at when I go to see it?

Here's a video of the actual machine in question:
 
I went down the same path last year: build, convert, purchase used hobby-level, purchase small professional?

Two things convinced me that I needed to stay away from one of these types of mills:
1. Weight. These things are heavy, even the 'small' ones. I don't have the ability to move more than about 2500 pounds around my garage without paying someone to do rigging. Even 2500 is a stretch.

2. Power. The industrial machines usually require 220 or 440 3-phase - even the small ones. Do you have the budget to install a 3p converter in your work space, and do you have the amps to support it? My house breaker is an older 100amp job, and there's no way I was going to pay someone to install a new 200A panel just so I could buy a 3p converter, all to support a 'cheap' used mill.

I'm in the rust belt and unlike many folks in other parts of the country, I can go buy as many used VMC's, lathes, HMC's, and other equipment as my pocketbook can stand. All. Day. Long. I'm about 45 minutes from HGR Surplus (Mecca!) and I know of at least 10 used CNC vendors within 30 minutes. Despite being in the center of the universe for used industrial equipment, I simply didn't want to deal with the weight and power requirement. Maybe my next mill will be put in a new workshop with a big-old 3p converter and a gantry crane.

Having given you the two reasons I opted for a much smaller mill, Here are a few other things to consider with used equipment:
1. Spare parts. Are they available, and what do they cost?
2. How clever are you? If an axis or the controller dies, can you trouble shoot it? Are you savvy enough to know that you have a servo drive made by "XXX", but that "ZZZ" or "YYY" will work instead because "XXX" is a million dollars for a used one on Fleabay? What happens when the controller throws up?
3. Control system. The controls on the older machines are reliable, but all the ones I looked at lack quite a bit in features that the average Mach3/LinuxCNC/Whatever user takes for granted. How much memory does it have? Can you load a 3D gcode file without it running out of memory? Can it even do helical interpolation (i.e. mill a hole spiraling down) or more than 2.5d milling?
4. Features. I have a 24" 1080P monitor for my mill - pretty nice, and I'll probably upgrade to a touch-screen soon. You're NOT going to upgrade anything on those old machines like I can on a PC-based system unless you totally gut the thing. Yours will keep running and mine my have the rare Windows tantrum, but you've got a 6" green screen.
5. Enclosure. You want flood coolant. You need a full enclosure, or plan on building a shower curtain and steel baby pool for your mill. Here's the thing - once you get a CNC mill, you want to mill everything to death. This makes a staggering mess - chips all over the place - and an enclosure is just the ticket. Why not hold out for something that already comes with a diaper?

Plenty more to think about than just the above. It's smallish, looks rugged, moves fast, and has a swank tool changer - but do you really want that monstrosity? What if you have to get rid of it? Think about how easy to sell that thing vs. a hobby-level CNC mill. Tons of guys around willing to cough up a couple of grand for a hobby mill you have 35-4500 in. Not many people want a sweet-running Tapemill, even at 1/3 what you paid for it.

Good luck
-Spumco
 
I don't know if it is of concern to you, but it was for me when I was buying my mill, was the ability to also use the machine in manual operation. It appears that the machine you're looking at is strictly CNC, which may be exactly what you want. I have a BP EZ Trak which I realize is a dinosaur in the world of CNC machines, but for my hobby use it does most of what I want. An important point that Spumco pointed out is the availability of support, parts, etc. Although it isn't great, there is still some support for the EZ Trak as well as numerous available retrofit packages. I'm not so sure about that P&W.
Just some food for thought.

Ted
 
Points all well taken guys; thanks for the input. I looked up more about that tapemate and saw some side profile pictures and it really is a lot bigger than it looks in the video. A little discouraged, I almost cancelled my appointment to look at it. But I didn't have anything better to do, so I went and looked at it anyway. Good thing I did, because the guy is prepping another machine to sell; something more like what I am actually looking for - a "bridgeport"-style CNC mill. It's a Lagun-matic 110.

20170225_110906.jpg 20170225_111800.jpg 20170225_114537.jpg 20170225_120856.jpg

He said it was his first CNC machine and he no longer needs it because he has a swanky new machining center (I saw it, it's swanky). He retrofitted it a few years ago with all AC servos with Allen Bradley Servo drives. The induction spindle motor was replaced with a servo, eliminating at least 2ft of overhead space. It isn't pretty, but it works. I'm going back tomorrow with my brother in law's father who is a retired machinist; I want to have someone with a trained eye look over the mechanicals before I open my wallet.

I'm not scared of the frankenstein control system. I'm a hobby machinist by night, but a Controls Engineer by day. I was a Controls Field Service Technician for years also. My experience with CNC systems and servo positioning is limited; I mostly deal with induction motors and VFDs, and programming PLCs, but I expect to find this stuff to be similar enough. And if I can't figure out that Delta 10 control system, I'll just rip it out and start over with a PC-based CNC system. That was my original plan anyway.
 
Good to know you've got a handle on the electronics. If you can do PLC's, you can manage the axis/spindle servos.

I'd just be afraid of the wiring - does the seller have some sort of diagram/schematic for the retrofit? Looks like the wireways are just there for looks...

Good luck, hope it works out for you.
 
spumco said:
I'd just be afraid of the wiring - does the seller have some sort of diagram/schematic for the retrofit? Looks like the wireways are just there for looks...
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Click to expand...
no documentation on the retrofit. But the original prints should still be more/less applicable. Same signals that went to the old drives go to the new drives.

I've gone swimming in deeper piles of wires than that, without any documentation at all, and still gotten the job done.
 
I can't really comment on the electronics, but it sounds like you've got a good background to deal with that. The Lagun mills are really good machines. I believe they are a more robust machine than the BP. Good idea to have your machinist friend take a look at it, because even great machines get worn out.

Ted
 
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