Old Mill Drivel (?)

Going forward, while I’m not even sure of what sort of things I might be making – not that I have any shortage of ideas – I am sure of one thing: I would want to base a portion of my work around the capabilities of a milling machine. A milling machine in fact has become more or less central to the stuff I have ben doing and I want to do going forward. I enjoy milling as a work activity and I enjoy the benefits a milling machine brings to my work. Tremendous rigidity, safety and accuracy makes it a winner for me. I like making chips.

Someone commented here a while back, annoyed about something (I forget what it was), that I was like the guy with the hammer where everything he looks at is simply another nail to be struck, except for me it was the tool was the milling machine not the hammer.

And… that assessment has become correct in many respects and I don’t feel slightly bad about it. I gotta say, who gives a f*ck really what machines another person uses in their work? Some would appear to think that there is some sort of narrow list of ‘approved’ types of equipment for woodworking, but not me.

A lot of woodworking operations that I did in the past, using a variety of means, are now things I typically tackle with a milling machine. I would say this tendency has become more pronounced as time has rolled on. Saves me a bunch on MDF costs at the very least, not to mention the unpleasant dust and disposal issue with that material. At my old shop I had a dumpster in the yard I paid monthly for, but in the new shop have no plan for a dumpster. There’s no place for one to go.

But, I can’t fit the Zimmermann mill I have now into my basement as it is too tall and I am not prepared to cut a hole into the floor or build a space outside just for it – though I did run through the possibility in my mind. Also, that mill is old and tired and in order to get up to snuff really could use a significant rebuild, and done properly – I’m talking about checking geometrical relationships between parts and scraping/planing/grinding to get things to a spec closer to when the machine was new – is costly. Oh, it is still cheaper in most cases to rebuild an older machine to new specs than it is to buy a brand new machine of the same quality, but still, it’s still expensive. Factor in too the issue simply of lifting and handling the very heavy parts properly, the space you need, the time that goes by with a machine sitting in some state of disassembly…. that’s why there are lots of old mills for sale out there that are in varying degrees of ‘worn’ condition.

Considering my current machine and what I have learned about it, what I have found to like and what I don’t like, naturally informs the search for something with which to replace it.

My current machine is not without its shortcomings, some of which associate to age and condition, and other aspects which relate to machine design and the options it has or does not have. If the machine does not come with the options you need, in many cases obtaining them separately will be difficult. Better to get them with the machine at the time of purchase if you can find something like that available.

For some strange reason, my Zimmermann has powered x-, z-, and main table rotation, but no powered y-axis. I wish it did have powered y-travel. They did add that functionality to these machines in the 1980’s, as an option, but that doesn’t help me any.

Hand wheels are present on all the axes of movement on most mills, and I’ve found a long session of turning hand wheels back and forth the appeal of doing more of it does tend to wear thin. How interesting can turning a hand wheel be really? I think I’d prefer less use of hand wheels and more use of things like shift levers and toggle switches, etc. to activate powered travel, with hand wheels as backup and for fine setting.

I think a machine with better ergonomics would be nice too, as sometimes I find myself in contorted positions with the huge Zimmermann trying, say, to control x-movement with a hand wheel way over to the right while the table and the object being cut on the table are way over to the left.

I also do not like tool mounting to a spindle by way of a collet nut. Zimmermann did it this way because the machine is so tall that you would need a stepladder to be able to tighten the more conventional tool holding mechanism of a drawbar, accessed from the top, and for some reason a powered drawbar arrangement was not employed,.

The FZ-5V has oil and grease ports at various locations, and a central lube pump for the saddle ways. I like having a convenient central lubrication system or even central automatic lubrication. This is common to many machines, just not the Zimmermann.

The Zimmermann is old and has not been rebuilt, but for working wood, for the most part the loads are so light on the machine that the machine’s areas of play from wear do not tend to present themselves in any sort of problematic way. The exception being the worn quill which has rotational slop, precluding the use of the right angle attachment, and sufficient stickiness in travel that it takes far too much exertion to operate.

The Zimmermann head can tilt left and right 90˚, however in practical use the amount of tilt has to be less for most tasks as the sides of the head, the pulley housing etc., hang down lower than the milling head itself, so you can’t put the milling head too close to the work table. Also, once the head is tilted, the end of the cutter will then be sufficiently far to the right or left that the room left on the milling table is on the small side.

As a design, having a heavy head mounted to a sliding ram by means of a joint which allows tilt for and aft seems like a recipe for having slop in the assembly. I think a lighter head, without such a heavy motor stacked on top, might be preferable in most cases, but I’m not too preoccupied with this aspect otherwise.

The Zimmermann mill has a decent range of spindle speeds, from 56~5400 rpm. Most regular milling machines only run up to 2000 rpm or so. I would like to have higher spindle speed capacity by some means, whether that is built-in, comes by way of an accessory, factory made or otherwise, or can be done via a Variable Frequency Drive (VFD).

All in all the FZ-5V has been a great machine and has lead me to change work approach for the better, and if I had the physical room for the machine and an easy means of moving it I would probably be keeping it. That’s not the case however, and I have been keeping my eye out for a replacement for a while now.

As a slight aside, funny enough one of my dream milling machines in the realm of pattern-making came up for sale somewhat recently on the market, another Zimmermann no less: a mid-1980s FZ-4 in what looks to be excellent condition:

I know it might not be immediately apparent, but the machine in the picture stands 10′-4″ (3.15m) tall and weighs some 3.5 tons. It’s huge! But the controller, visible to the left, should ameliorate some of the ergonomic challenges that might otherwise associate to operating mills of this size. As I write this another one of these has gone up for sale in Germany, after there being none on the market for several years. Weird.

The mill I have now is a knee mill (the work table goes up and down). The type of mill pictured above is called a bed mill (the table height is fixed and the head goes up and down). Like my mill, it is badged and accessorized by Zimmermann, but is actually made by the manufacturer TOS in (former) Czechoslovakia. It features a much bigger work envelope than with the mill I currently have, but alas it is simply way too big, so it is a total no-go for me. Sometimes I think in a parallel universe, where different projects and situations had materialized over past years, and I hadn’t got cancer, I might well have ended up with a shop space in which I had a machine like the one above.

Anyway, back to this part of the multi-verse.

Milling machines have been developed since the mid 1820s, their design essentially being the addition of a movable work table to a lathe. The earliest mills were horizontal mills, and thus these are the most common type of early milling machine. The development of the vertical head arrangement did not come until later.

Machines that could deal with working on all three axes, x-, y-, and z-, were termed ‘Universal Milling Machines’. The most well-known of this type, though not the originator of the design, today is the Bridgeport, a knee mill developed in 1936. The term ‘Bridgeport’ has become near synonymous, here in the US at least, with ‘milling machine’, as have other brand names, like ‘Frisbee’, or ‘Heroin’ (developed by Bayer), say..

Now, not all knee mills are exactly alike. I’ve become interested in one type more than others, and I’d like to give a bit of background about the type I prefer now, starting with the way-back history and bringing it forward.

A type of universal milling machine was developed in the US by Van Norman in the late 19th century. Van Norman, which started out as a manufacturer of watch making equipment, was based in Springfield Massachusetts, about 40 minutes south of where I live. This is their design, circa 1895 or so:

(Illustration, along with others like it below, are taken from the lathes.co.uk site)

The table is carried by a knee attached to the column. X-and y-axis movements of the table take place atop the knee, while the knee itself is raised and lowered by a jack screw from below, guided by ways on the machine’s main column. Y-axis movement also occurs on top of the machine’s column, as the head there is attached to a sliding ram. The part sticking up in the air which looks like part of a corn cob pipe is an extension arm to carry a horizontal spindle nose, which thereby allows the machine to be used in a horizontal milling mode. The milling head is shown in an angled position in the print ad above to demonstrate that the machine has such a tilt-head capability. The head is able to swivel over to a horizontal orientation, where it then is used with the ‘corn cob’ support to support a horizontal spindle. This capacity, to work in both horizontal and vertical modes, was termed ‘Duplex’. To change modes, one simply moves the ram back, and the cutterhead is rotated counterclockwise to a stop. Then the knee is raised to bring the work up to the spindle.

Here’s a pic of a later machine with that style of ‘duplex’ capacity in view, the horizontal spindle installed:

Here’s a look at a later model, after the electric motor had become the standard choice, replacing line-shaft and belt based drive systems:

Putting the motor up on top like that is a curious design choice, given the amount of weight it is adding, but maybe the Van Norman carries that extra weight without complaint.

In the early 1900’s the German firm Thiel, and then the German firm F. Deckel in the early 1920’s developed what are referred to as ‘precision universal milling machines’. At this time the US was the world leader in machine tool manufacture and had a strong European market presence, with sales representation in many countries, including Germany, so it is likely the designers of the German machines saw the Van Norman at a trade show or similar.

The first Thiel ‘duplex’ machine appeared in 1914 -notice how similar it is to the Van Norman shown above, demonstrating that Van Norman’s mill was very likely the origin of their design:

Again you have the dual means of accomplishing y-movement, namely on top of the knee, and on top of the column via the ram. This allows the table to be kept relatively close to the column, which reduces a potential source of deflection.

My Zimmermann milling machine also has y-movement via both work table and its ram, however the ram movement is on the coarse side and not easy-moving and finely controlled by a hand wheel or drive motor. Instead you have to loosen gibs to enable it to slide, and then rotate a hand crank to move it to and fro. It is not an action taken while actually milling something, but a move undertaken when setting up, then the ram is fixed in place with a couple of clamping screws. This is not the only option however, and machines with finely adjustable powered rams exist.

By the 1930’s, electric motors were more widely in use, and some refinements had taken place. Thiel’s machine looked like this:

The big change besides the mode of power delivery is the employment of two spindles, one being horizontal, and the other vertical. To use the horizontal spindle, the vertical head and its carrier would be removed and an overarm support casing fitted in place. Also note that the work table is bolted on to an apron, and can thus be removed so that other accessories can be fitted.

Deckel developed their earliest design of mill out of a company need to improve the making of camera shutters, starting their milling machine manufacture around 1917:

On the Deckel design, like the Thiel, the table has been replaced by a mounting apron, upon which, in the example above, is mounted an accessory (a dividing head) or which could be a milling table, of which several versions were offered. The significance of this is that the table can be moved out of the way entirely and taller objects can be clamped directly to the apron so that the ends of the pieces may be directly machined.

I can think of lots of applications where it would be desirable to take the table off and attach parts in various orientations in the freed-up space, and this is something not possible on knee type or bed-type milling machines.

Another aspect to this is that with knee and bed mills, any damage done to the bed by over deep cuts with drills or mills, can be a tough call to deal with. On a machine like the Deckel/Thiel type, if the table is damaged it can be readily replaced, comparatively inexpensively, with another table by removing a few bolts.

By the 1930’s, the Deckel design had evolved a bit and this settled into a form that more or less continued going forwards. The venerable FP-1:

The horizontal spindle greatly adds to the machine’s capacity work-wise. By taking the attachment with vertical milling head off of the machine, the horizontal drive spindle may be accessed. On some designs along these lines, the head can be tilted out of the way or swung out of the way, or extended far enough forward so that it does not need to be removed.

The machine above has a dual-tilting (left-right as well as front-back) and rotating ‘universal table’ mounted to the apron, which is a somewhat common option to find to this day on this type of mill. It tilts left and right 30˚, and frontwards 30˚ as well. The table also rotates a certain amount left and right, about 20˚.

I can see in my own work where that table angling capability could come in handy at times. With a bed mill or knee mill, generally the mill head is the part being rotated to an angle, and afterwards must be ‘re-trammed’ to perpendicularity with the work surface, a process that can be a bit tedious I have found. With the Deckel style of mill, one could choose to angle the head, or one could choose to attach the universal table, each offering certain advantages in certain situations.

I mentioned that the 1930’s design was more or less the form the mill took going forward. There have been more than a few technical improvements along the way of course. Here is the latest modern day descendent of that mill, made by German firm FPS (made up of ex-Deckel employees):

I’m not sure of the price, but I believe it to be north of $75,000, and a lot more if you go for accessories. Too rich for me, but one can drool over it at least, if it is the sort of thing that floats your boat. It floats mine!

This configuration of milling machine, especially if accompanied by a decent selection of accessories is, to my way of thinking, an arrangement offering tremendous versatility. The Deckel style of milling machine is figuratively the Swiss Army Knife/Leatherman of milling machines. What comes with this of course, just like the Festool tracksaw you bought and then decided their vac would be a nice addition, and then before you know it you are deep into the accessories: the cost of course climbs and I would wager that most accessories see little use for most folks. Still, ‘collect the whole set’ remains a powerful motivator for some – I’m half-surprised it hasn’t been given an official term by the American Psychiatric Association.

What makes A Deckel design mill different, say, as compared to the standard, a Bridgeport mill? For starters this type of machine has both horizontal and vertical spindles. You can only operate in one mode at a time, but it opens up all sorts of possibilities with a tool that can be oriented horizontally.

Unlike a knee mill or bed mill, on a Deckel style mill the work table can be removed entirely, leaving behind what some term the apron, which itself has numerous t-slots and therefore offers a mounting option for taller or vertically-oriented parts.

With options, this mill can be configured to solve a vast number of milling tasks. For my interests and materials I work, there are high-speed heads available offering over 6000 rpm. There are fine boring heads, slotting heads, dividing heads, tilting and rotating tables, etc..

Deckel mills are relatively abundant, especially in Europe, and there are quite a number of ‘clones’ produced in various countries, many under license to Deckel. Other German manufacturers copied the design too, like Maho – in fact the list of Deckel mill clones out there is quite a long one. Imitation is, as always, the sincerest form of flattery. Clearly the design of these mills was a winner with customers as well.

The Deckel-produced range of mills break down into 5 sizes, more or less, with the mills numbered from FP-1 as the smallest on up to FP-5 at the largest.

As far was what fits into my basement, I am limited to the two smaller sizes, FP-1 and FP-2, and an FP-2 machine would likely need the apron removed to go through the doorway. After considering it a while the FP-2 is preferred by me for its greater work envelope, despite the likelihood that some dismounting will associate. The weight of the machine, too, which is around 1.5 tons, is something within the range of manageability I think, but definitely a challenge. I grow a little nervous though thinking about whether the basement slab is going to be sufficiently strong enough.

Everything has its pros and cons, and one needs to figure out which tradeoffs are acceptable. For instance, Deckel mills started out as relatively simple devices back in the 1930’s, but by the late 1960’s began to be factory-equipped with all sorts of electrical and then later electronic control systems, the electronics and wiring for which required, tah-dah! – an additional large cabinet for the machine, or even two:

And with a 30+ year old machine you can generally assume that functionality of those electrics could be a matter of concern. There’s no shortage of machines which go for scrap for no other reason than electronic controls and wiring problems. If I was one of those electronics whizzes who likes digging into circuit boards and trouble-shooting – – but that is not me. I’m kinda wary, I guess, of machines with unknown histories and loads of wiring and loads of circuits, the parts for which are not always easily obtained, and the operational logic of which is also not so easy for me to get my head around at times. One need only look on the appropriate section of the practical machinist forum to apprehend the frequency of which one sees questions concerning electrical-challenges with these older machines.

So it is either an older Deckel, without complex electronics, or something similar. Deckel machines from, say, the mid-1960s and back might fit that bill, but then we move increasingly in the direction of the mill being likely worn out by this point and most likely having been taken apart and repaired at some point, and that sort of work is sometimes not done in the most expert fashion – you can tell when someone ham-handed, or who forged ahead despite having the wrong tool for the job, has mangled locknuts, marred shafts, etc.. Some seem to think that anything can be repaired with a pair of rusty vice grips, a BFH, and some sort of mangled pry bar.

Instead, I’m looking for a mill that has not seen production use, and has been used by an entity (we’ll call them a ‘professional’) who knew what they were doing and who performed regular scheduled maintenance on the machine. In other words, something that has been well cared for. Or maybe none of those things but a machine that has spent its life in some small prototyping lab where it was hardly ever used. Those gems are out there, but as often as not I come across them at times when I cannot afford them. This is my curse I guess, and hopefully not your situation.

And as mentioned earlier, the design of this class of machine is like a multi-tool, however unlike a multi-tool where all the various tools are attached and you pull ’em out into position, with the Deckel style mill all the tools come as extra-cost accessories. There are different types of machine tables, high speed heads, slotting devices, indexing devices and dividing heads, rotary tables, etc. And all those accessories, especially in prime condition, can be thousands each, not always though. Few of the Deckel mills I have looked at for sale on the used market come with any accessories at all. Maybe the odd one comes with two different heads, or another might feature two different tables, but not a whole lot more than than from what I have seen. Some are for sale without even a table attached, just the bare apron. So, if you start to add it all up, a mill in decent original condition (preferably) and a bunch of accessories (preferably) then the cost tends to widen the eyes a little bit. It’s all relative of course, it might seem cheap to some folks, especially in light of what a brand new Deckel/FRS can cost.

And if it is not a Deckel mill but a clone, then you will find that if the machine does not come with accessories you are highly unlikely to find them afterwards. The used market for Deckel accessories however seems relatively robust at this time.

There was a Deckel FP-2 for sale here in the US for a while in very nice condition but no accessories included -though it did feature a fabulous multi-angle work table with DRO readout of the rotary table angle – priced in the mid-$30,000 range. I was tempted to a point, and certainly had no shortage of drool to wipe up off of the keyboard, but I cannot allocate such resources to that one tool. I’m thinking a max. spend about half that number or less on a milling machine.

I’ve bought several machines from a distance with nothing else to go on but the seller descriptions and whatever pictures or, rarely, video they might share. One learns from these experiences of course, as after the machine has been received one can compare the reality of the machine with how it looked in the ads and how it was described by the seller.

I have done well enough in these transactions that I am not shy to do them again, but my caution does tend to grow over time. While I do not presume the worst about a seller, I do pay more attention to the things they don’t take pictures of, or of details they are fuzzy about describing, or details they seem to waffle about explaining. Lying by omission is commonplace and apparently effortless for some.

The standard machine dealer trick of rattle can spritzing of the machine to make it look fresher than it actually is -the rattle-can ‘resto’ – no longer impresses. Some sellers show pictures of the machine sitting on a pallet where the paint overspray of their efforts is quite obvious – I mean, c’mon, they could try to be a little more discrete about it than that! I think used machine sellers and real estate agents should get together and form some sort of advocacy group or the like, given that they seem to have commonalities in their approaches to the market. Do as little as possible, provide crappy photos and sparse descriptions – how does this manage to work at all?

It’s not hard to spray paint something poorly or inattentively and spray paint is often just a substitute for properly repairing and reconditioning a machine.

Actually, I now look at a machine with fresh paint with a certain degree of suspicion. Instead of a dreamy fascination with how shiny the machine looks, and the attendant fantasy that somehow creeps in and begins to convince that one is in fact getting a virtually new machine for pennies, I now am tending to steer well clear of such things.

I’m looking for a machine in an un-‘restored’ original paint condition, but not clapped out, or looking misused/abused, and ideally with a good number of accessories. Not easy to find things like that in general however. Not easy.

I have been looking at a lot at Deckel mills on the market, and at the same time I have also started looking at Deckel clones more closely. More on those and where this search has taken me in a follow up posting.

Have a Merry Christmas and/or Hannukah if you celebrate. It seems to be an exciting time of the year for those under 10 years of age especially. Our son, who is 3-1/2, has come to terms with the idea that presents are stuck under a tree in plain view and that he must wait several days before he can open anything. There was a lot of protest at first. It’s very hard to do it would appear.

I think as a species in general we are not much good at delayed gratification, especially these days.

Over and out.