Okay, so I have what might appear to be a stupid question. I have been studying the PM Research miniature milling machine. The original machine was made by Brown & Sharpe, and I believe that this is the original milling machine. Here is a picture:
Okay, so now here is the question: Where is the part which does the actual cutting? I am looking straight at the picture, but I swear that don't see it! Can somebody help me out here?
Right now, based on the photo, it looks like there's a fly-cutter in the spindle. That removes by undoing the drawbar in the back. It can then be replaced with a regular, plain-mill cutter arbor, or an end-mill holder.
However, because this is a 1/12 the scale model, you're unlikely to find either plain mill or end mill cutters to fit. The use of a fly cutter is a common practice for model mills.
I believe you may be correct in the prototype for the model ... though MANY early horizontal mills were quite similar.
The cutting tool goes on the horizontal spindle extending over and above the table. Most often, the spindle is extended with a "milling arbor", upon which the milling cutter(s) is mounted. There are several ways to accomplish this. The machine in the photo appears to be fitted with a boring bar instead of a milling arbor/cutter. This is just a rod extending from the spindle with a single-point cutting tool attached, and used to bore holes. I suppose it could be considered to be a horizontal fly-cutter also, as might be used to cut gear teeth.
A drill chuck or end-mill holder can also be fitted in the machine spindle if/as needed.
The outboard end of the milling arbor (when fitted) is normally supported with with a bearing attached to a brace extending down from an "overarm" ... a stiff rod (sometimes two) mounted parallel to, and above, the spindle. The machine in the photo does not have an overarm fitted. An additional brace is sometimes fitted from the overarm to the table, further increasing rigidity.
On Tue, 11 May 2004 10:58:59 -0700, "Lurker" scribed:
Ummm, I think that is the T slot on the machine table... I think this is just a shot of a old B&S horizontal mill with no cutting tool attached and nothing on the work surface... Pretty common for publicity or catalog shots of machine tools in the old days.
This shot, however, looks a little too clean for such an old machine, so I reckon that Papa-Mike has spruced it up, dropped a background on it and is quite proud of his very old and very capable machine tool. I dinna know how many are out there, but that is a fine example of one of the first B&S horizontal mills and shapers out there.
I have all kinds of old B&S catalogs and will see what I can find...
Thanks, fellows. I can visualise it now. I think what threw me off is that I was expecting to see a vertical spindle, and this one is horizontal. I guess that would make this a horizontal mill. I would have responded earlier, but the Gingery shaper book arrived earlier today, and I wanted to get started on it. I already have a lathe and a drill press, and now I want a milling machine too. I have decided to build the PM Research milling machine big enough to match the machines which I already have. I'm going to build the PM Research lathe first, though, and give it a six inch swing. I don't expect it to suddenly become unavailable, though I would sure feel funny if it did, and I had already built the shaper first, instead of the lathe. I should be ready to send away for the lathe kit sometime within the next few days. By the way, I plan on casting the six inch swing version in aluminum also, and my idea is to cast three copies of the bed first, so that I will then be able to use the "rule of three" to scrape the bed flat. That should give me three beds altogether: one for myself, one for a pattern (to replace the wood patters), and one to sell.
Yep -- horizontal spindles preceded vertical spindles for production work. It didn't take as much cast iron to make a rigid machine.
Beware that models may skip details which are needed in a working machine, but not really in a model. If you intend to *use* these, you really should consider studying real working machines, too.
And while they *can* be made from aluminum, they will lack rigidity (and wear life) compared to the traditional cast iron
Hmm -- that works best with flats which have equal dimensions, as you are expected to rotate one of the pair 90 degrees at every switch of pieces.
Another problem with using one for a pattern. Remember that the pattern should be a fixed percentage larger than the final product. The percentage is a function of the material chosen -- different for cast iron, aluminum, bronze, etc. So -- if you use it as a pattern, the next one will be smaller. Also -- you need to include extra material to machine away in each casting, so you can make a good surface afer removing the sand and whatever is produced by the contact between the sand and the metal being cast.
So -- after all of this -- I *have* to ask whether you are a troll. :-)
Hmmm...gives me a good explanation when somebody asks me why the machine isn't "modern".
I don't yet have the Gingery book on how to build a milling machine, but I'm going to be sending away for it soon. Actually, today I'm going to send away for another copy of the charcoal foundry book, because I've read the one I have so many times that it's beginning to fall apart.
I haven't yet done any aluminum casting, so I'm going to make my machines with aluminum first, to gain some experience before moving on to the "hot stuff".
I agree, and eventually I would like to build a surface plate which will enable me to do ninety degree rotations. these three beds will be more like straight edges, I suppose.
I will keep this in mind, and design my patterns accordingly. Between the two of them, Dave Gingery and Papa Mike are going to put me in the machine tool business. I love old machines.
The model is not a 'universal', and does not have the swiveling table.
The PM Research miniature machines are really neat machine shop projects. They have most of the machines of a full machine shop available as individual 'rough castings' kits. When completed, they are fully functional, but not really intended to USE as most parts are made of aluminum, and the scale sized controls are too small to use easily. Still, they are quite capable of making tiny chips.
Dan, this is good to know, because when I build this machine in a useable size, I will want to give it the swiveling table. It will be awhile before I will be ready to build this one, since I will be building the lathe and the shaper first, but this will give me something to think about in the meantime. I probably will send away for the book which Papa Mike sells that has this machine pictured in it, especially since the book is only six dollars anyway.