Pondering a mill

Go for the table travel. You don't need high speeds for home shop use because speed of production isn't an issue. In fact if you run milling cutters and drill bits nice and slow you rarely burn one out and as most one-off milling ops have a considerably greater set up time than machining time it doesn't really affect the total time for the job. My Bridgeport clone has a top speed of 1800rpm but I can count the number of times I've had it at over 600 on the fingers of one hand.

If you ever need to flycut the face of a large item you'll appreciate having as much table travel as possible whereas you'll rarely miss speeds over 1500 rpm. A very low slowest speed is handy too. Something around 80 to 100 rpm for big boring bars, reamers etc.

-- Dave Baker - Puma Race Engines

A moveable knee machine is much more versatile and rigid than a round column mill drill. Yes you will need enough table travel for the type of job you envisage but not at the expense of resorting to a mill drill which will limit your vertical movement to that of the quill without risking losing registration with the job.

Just my 2p

Bob - VMC with head raising block user

I am strongly considering a Warco VMC with R8 spindle. I see that Bob metions a raiser block, is this a Warco option or was it home made?

Brian

Boo

Hi, I have used an RF25 (round column) mill drill for the past 4 years and it has been a useful but very frustrating machine. Anything that requires a change from short tooling (end mill, etc) to longer tools (large drills, large face mill) means the head has to be raised and alignment is lost. For this reason alone I will be changing it for a VMC as soon as funds allow; even though I will lose some table travel. I currently have a MT3 taper but will replace with an R8 because I don't like bashing the drawbar with a lead hammer every time I want to release it.

You don't indicate which of the GH machines you are thinking of if it is the GH Universal (square column) then both that and the VMC (knee type) will not suffer the same issue. If you are considering the Major GH that has the round column then I would strongly advise against it, particularly as you mention a range of sizes and possible uses later on.

I haven't used all of the available speed range on mine and the machine stays below 600rpm most of the time. However, if you are going to machine a lot of Aluminium with small diameter cutters then faster is better. The other issue I would look at is the fact that the VMC comes with a (free?) power feed - you won't believe how boring it is winding the table backwards and forwards time after time. A very useful addition in my book.

I also haven't used anything near all of the available table movement I have and unless you are going to build some very large engines I suspect that 95% of what you have identified will be well within the range of a VMC. Using it as a jig borer for frames is a good idea (especially if you fit a DRO) but you only need one set of frames per engine and the additional cost of laser cut frames is fairly reasonable these days.

My use is fairly similar to that you have outlined and my current priorities would be square column/knee type machine, R8 Spindle taper and power feed to table. With regard to the speed range I believe both the belt drive (VMC) and the GH types each leave a little to be desired. Although the geared head is easier to change speed they are usually a little more limited in the number of speeds available and in my experience (my friends actually) they can get a little noisey when they have had fair use. For those reasons I believe that a belt drive (smooth, quiet) and a VFD to give a stepless speed range is the answer albeit at greater total cost. I must admit though that the VMC lowest speed is a bit high for fly cutting etc and will be one of the first things I address when (if) I can get one.

The other cost I would budget for is for a reasonable DRO system. This makes life so much easier and would be particularly useful if you are going to do much jig boring with it. I currently have one of the cheap chinese scales on each of the axis of mine and would not be without them. Co-ordinate drilling is a doddle.

I'm sure you will get a range of opinions and in my experience only you can decide which is the right machine for you. I am a great believer that if you really want or like a particular machine then get it. You will find much less fault with something you like. Too many times I have heeded the advice of others to find myself picking holes in it and every time something is not quite right thinking I should have bought "what I wanted". If it feels right to you, you will probibly enjoy using it and the more you use it the better you will get.

Anyway, hope this helps you to sort out what is important to you. The most important thing is to get a machine and start enjoying it. Don't forget though as I suspect we have all learned with the lathe, leave plenty of funds for that essential tooling.

Best regards

Keith

Fully endorse comment re maintaining alignment. Know this to my cost. Long table is good. You can mount the vice and align it at one end, this leaves enough room for a rotary table etc at the other end. Saves all the hassle of re-alignment.

You just break them! The small diameter end mills and slot drills used in model engineering need high speed - in fact most machines don't go fast enough on spindle speed, including lathes and drills. Try putting a No. 80 drill into steel at anything below about 8,000 RPM and see how long it lasts.

Dave Baker wrote:

snip

And thats where the use of a quality minidrill off the spindle is a nice addition.

Joules

If you top post you go. Click

-- Dave Baker - Puma Race Engines

Hi Brian, My VMC is a genuine Myford that I bought new around 1986. The raising block was bought via small ads in one of the ME mags in the mid 90s I had contemplated a home brew one but did not have the welding capability or a lathe big enough to swing it comfortably.

The block I bought was turned from solid bar.

Well worth having though as it adds nearly 100mm extra daylight under the quill

If some photos and overall dimensions of the raising piece would be useful, please let me know but give me a couple of days to reply as I'm going into hospital tomorrow for a day or so.

Regards

Bob

I know it is a few extra quid but I'd suggest the GH Universal. It has a far better table travel than the VMC (the main reason I didn't buy the otherwise excellent machine) and it has a dovetailed column which get's around the loss of head position if you need to raise or lower the head mid job. I looked at all of the machines and ended up with the super-major (basically the same as the GH Universal) which is the same in essence as the much discussed RF45. It is, IMHO, an excellent, robust and accurate machine. If the budget will stretch, I'd go for it. Of course if you can find a good used Myford VME within the budget, I'd go for that instead!

Regards

Mark

Thanks to all who answered, I wasn't totally plain in my post so I'll try to clear up any confusion here :

The machines I am considering are the Warco VMC and GH Universal, both of these have square columns with dovetails. From the pictures the VMC looks like a lot of machine for the money, and there is a kit from Hemingway that gives a bottom speed around the 50 rpm mark (I presume this fits the Warco machines as it was probably designed around the Myford, does anyone know whether this is true ?)

..snip..

Interesting point. Others here have differed over the importance of a longer table travel, I just want to know that I won't regret not getting a bigger one later on. The loco frames issue is a long way off (even assuming I ever build one) but I don't really want to be faffing around making do with bodges if it's possible to buy one big enough in the first place. Both machines are plenty big enough for my current needs.

I'm not clear what are the advanteges of the knee over the travelling head of the GHU, can you enlighten me on this ? The GHU has a spindle to table distance of 17 inches odd whereas the VMC only has 13.5", also the spindle stroke on the GHU is 5" vs 3.5" for the VMC so on the grounds of clearance the GHU seems to win out, or am I misreading things ?

...snip...

True, but I still need advice regarding the kind of capacity I need - I've next to no milling experience at all and I was slightly put out to find that it seems to be entirely impossible to mill a flat on an 8.5" bit of bar on my Boxford lathe. I don't want to buy a mill and find I've a similar problem in 3 months time :-).

Very true and a good point. Actually atm I'm still open to ideas and would consider buying second-hand as others have suggested to get a good selecton of tooling.

I see that Warco are exhibitors at the forthcoming Guidford MEE I may go along and have a chat at the Warco stand. What's this gig usually like does anyone know ?

Thanks,

Thanks for the reply Bob Since I will certainly not be buying the mill before September I will contact you when, and if I buy it. I want to get a really close look at one, probably at the Bristol SME exhibition. You are lucky to have a genuine Myford they seem as common as hen's teeth these days and very expensive! I am sure all the group wish you luck for your hospital visit

Regards Brian

Remember the Myford machines are just imported milling machines that Myford re-worked. The quality of the imported machines has improved a great deal since then. Personally I'd go for a good second hand machine, but if you're not sure what your buying I can see the advantage of a new machine.

One thing no-one has mentioned yet (in this thread) is rigidity. The GH Universal may be a "larger" machine but it weighs 320kg against the VMC at 415kg. This would certainly suggest to me that the VMC is a more robust machine. FWIW I'd spend my money on a VMC -it's a propper milling machine, not a mill-drill.

Regards

Kevin

Boo

Hi, interesting discussion you have started here. Although I have been planning to buy a VMC for nearly a year I also have some concern that I might not be buying what I need. However, my alternative would be a secondhand "industrial" machine not the GH in any of its' guises.

Your concern seems to centre around the capacity of the two machines and here I believe is a basic difference between the design criteria of the two machines you are considering. In my opinion the VMC is as Kevin says "a proper milling machine" with a design priority of rigidity and shear mass of cast iron which significantly aids vibration damping. A vital attribute when you are milling with anything like a reasonable cut. On the other hand, the mill-drills (round or square column) are I believe designed to give the largest capacity and widest capability in a given space, a vital attribute if you are limited for room and envisage a wide range of uses. I know from my aerospace career that you can make very light structures extremely rigid so my main interest is really the vibration damping ability of increased mass.

My decision to go with the VMC was based on the fact that you will face the problems of lack of rigidity/damping with EVERY job you do large or small, for me only the very occaisional job will be outside the machine capacity. This was shown recently when I completed one of the John S toolposts, milling 10 off 1/2sq slots with a mill-drill is a long and boring process that shakes the machine constantly. Here I think you have to decide which of the criteria is most important to you. I'm not saying that the GH machines won't mill properly, of course they will although you will need to take more care with speed/feed/depth of cut. In my book, the advantages of better rigidity/damping are exhibited every time you use a machine and far outweigh the benefit of larger capacity

Whatever you decide I'm afraid you will always find that any machine you buy is a bit too small to do something or other. We used to find this when buying some very large and very expensive machines at work - they were ultimately just a few inches too small.

I can't really comment on the different attributes of square column against knee type, my very practical outlook says that all slides will have some clearance and I would prefer to keep the length of the levers (slide to base/column joint) as short as possible. So here in my book the knee type wins hands down.

I've not been to Guildford MEE but by all accounts it is a good weekend. I have visited the Warco stand and their showroom and the oportunity to see and touch the machines you are considering side by side before spending your money is well worth the trip (300miles for me). You do however, owe it to yourself to visit a few machine tool dealers and look at some of the smaller industrial machines in the same price range. From my experience you will be surprised what you can get for =A31500 but also (if you are like me) a bit intimidated by their poor appearance and potential wear. The potential cost of a rebuild for some of these machines even if possible is frightening. Don't forget that in industrial terms a 1 1/2 ton Bridgeport is considered "very flexible but a bit lightweight" so it always pays to "colour" advice by which direction it is coming from.

I hope you get plenty of advice to aid your decision as I personally find it a difficult one; but I must say as my experience of milling with small machines increases my determination to get a rigid/heavy machine grows stronger by the job. I have already accepted that any machine I buy will be too small for something I need to do. Personally, I do not have sufficient experience to identify a "good" secondhand machine so I will have to go with the VMC and accept its' size limitations. Every VMC owner I have spoken to (yes I accost all sorts of people at shows etc) has said that it is a "real" milling machine just smaller. Not sure this helps really but only you can decide if being able to occaisionally do larger work more slowly is more important than not wasting excessive time watching the machine take light cuts on every job you do. Good luck.

Best regards

Keith

As I've said elsewhere I think that the VMC is an excellent machine but unless you plan to use it on a specific type of job that fits within it's range, you will probably find the table travel is a limitation. The problem is that once you have a milling machine, like a lathe, you tend to find no end of jobs you would like to do on it. The reduced table travel will limit the jobs you can undertake and the scales you can work with.

The question of rigidity is, as Keith says, important. Having not used a VMC I can't comment but I can say that I have never been conscious of any lack of rigidity on my Super Major (in essence a GH Universal without the swivel table but with power feeds) even when used near it's limits.

Having spent months agonizing over the decision myself, I can say that there is no perfect solution (unless you have an unlimited budget - even then you'd probably choose to buy several machines) but I think the key is to find the machine that offers the most flexibility so that you do not unduly limit your future options. In term of priorities for general use (and sticking my neck out here!) I suggest:

1) Size/weight to suit available space, - It must fit, you must be able to get it there and it must not fall through the floor! 2) Dovetailed column (for either head or table) - round columns loose their alignment as soon as the head needs to be moved. 3) Table / Head / quill travel, 4) Rigidity - within reason this is not an serious problem, most machines will do what is required of them assuming they're not in a production environment (and they're not knackered). 5) Spindle speeds - again, not a major issue unless used in a production environment, although not being able to run below say 150 rpm may be a problem for boring / face cutting.

I guess that build quality fits into the sequence somewhere but my brain is too addled to decide where!.

I'm sure that others will disagree with my priorities but you have to decide which fit your requirements best - flexibility is the key!

Mark

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Looking at these two on the web the GH Universal has a larger table and greater height but a lower speed range. The VMC has a higher speed range but smaller table even thought it is heavier but not by a lot.

Having used Mill drills since they first came out I can say that the biggest factor I found doing jobbing work was the depth to table dimension, followed by the long axis travel. Using a dividing head with a collet chuck only leaves you a very small window to work in. No way can you get something like a 5/8" drill on a VMC with DH on the table.

Speeds are also an issue that's not easily compared as one is belt drive [ VMC ] and the GH is gear driven. It's not obvious from the web site if the GH is available in three phase to retrofit an invertor plus the increased speed in a gear head could cause noise. It may be better to go with a speed increaser head for small cutters.

The VMC head is a throw back to the conventional mill drills and these suffer from large differences in pulley diameters to get the reduction needed with the disadvantage of low wrap around on the small low speed pulley. This is the speed that need to most torque and because of this design fault it will slip the belt. Over tightening will only partly cure this but also take the top bearings out, don't ask

So basically both machines need to be addressed on speed issues.

My personal choice given these two would be the GH and address the speed issue as needed

-- Regards,

John Stevenson Nottingham, England.

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From what you say, it sounds as though some mills have a solution to this problem but it's not used here. Why's that ? Cost ?

How do better machines handle it ?

-adrian

I had recognised the relatively small depth but had thought that I would just add a 6" or 7" riser block, is this not a good idea? Does it introduce any further issues?

I fully agree with your comment and had decided to go 3phase and inverter with a "poly-vee" set up. Would this be OK? I had considered that the GH type would be more problematic (grear wear/noise) to increase the speed although possibly no trouble to decrease. Am I being too concerned about gear wear in this situation given that they claim to be "close tolerance"; with my sort of use (3hours/day?) could I expect a reasonable life at say 150% of the current top speed?

With these modifications to address speed issues on both machines and also provide power feed/stand on the GH the price goes up to well over =A32K with the VMC at just below =A32K. Prices at which I feel I should be able to get a reasonable basic Bridgeport (if they still exist) even from a dealer. I had thought of a Boxford VH30 (small table travel again) or possibly a Marlow as they both seem to be available from schools etc at the moment. Any thoughts?

Thanks again for your help, best regards

Keith

Only worry I can see there is whether you can get close to the table with the riser block on or if that will stop you getting near for the jobs where you need to clamp direct to the bed.

Sorry, can't honestly answer that as I have never hear a GH running. Bear in mind that gear noise rises proportionally to speed and 150% 'could' be more than 1/2 as much again.

Only real way would be to listen to one under power and note the increase from 3/4 speed to full and 'project' that up to 150%

What about the Chester 626 mill?

-- Regards,

John Stevenson Nottingham, England.

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