Let's talk milling machines

[stof]

I dont normally post . ,but live in s.a. and a avid reader of most of the post. I especially enjoy your post Hennie as they have been very informative and relevant as we seem to share very similar interests. I went through exactly the same process as you 2 years ago. So my decision was absolutely a quill. Expense was an issue So what machine. Started to look at 2nd hand bridgeport and felt i would never get one in good order. Ended up with with on for 2000$. I needed to spend 600$ more on complete rebuild, done by myself. this was tough but completely doable. Extremely happy now with it. I also learnt a huge amount in the process and have a mill which is not absolute perfect due to age but totally happy with ability and quality.You need to be patient and follow all leads and you can and will find a bridgeport in good enough shape. I do have some contacts which I can share with If you like.

 

[timo_gross]

Deckel FP1 was made in 1937 and still mills to .001” which does me.

Is the machine a political refugy? When was it moved to UK? (just curious). What tool taper does it have?

Question to the quill discussion: If there is a horizontal drive can this be used to put a drill chuck into it? Then the y-axis can be used for drilling?
Maybe a problem with the travel, but it would avoid moving the knee up and down for peck drilling.
I saw some larger Taiwanese machine, it had a power feed on the quill and a retrofit tapping function on the quill as well.
Is tapping and quill feed something that is commonly available?

Greetings Timo

 

[HennieL]

I do have some contacts which I can share with If you like.

Thanks for your post, Stof. PM sent regarding your offer to share contacts - much appreciated.

 

[Jules]

Hi Hennie, I have a Bridgeport clone with a variable speed head from 65-4500 rpm.
Whilst it is not as rigid as the solid head vertical machine you show it is worth considering a compromise.
It is very very versatile. You can swing the head left or right, slide it in or out on the ram, tilt it for and aft and rotate it.
You do had a quill and with 4500 rpm it will drill quite small holes no problem.
You don’t have to re-setup in another machine. The quill also has a powered down feed (or up ) which can give nice results when boring.
I guess it depends how often you need to remove large amounts of tough material.
I certainly wouldn’t swap it for a less versatile machine.

 

[clockworkcheval]

In traditional machinetools the slides need a minimum of play in order to move at all. When you put load on the table first the play will be squeezed out, then the surface roughness will be pressed in and finally the form tolerances will adapt to each other. All this results in a lot of springiness under light load, even with precision machines. Under heavier load they are OK. A good but expensive solution is to use pre-loaded harmonica gibs for the ways. A cheaper and quite effective solution for existing machines is the use of thin industrial PTFE tape on the gibs. It will not only allow light pre-loading but it will also reduce slip-stick.

 

[L98fiero]

I would really appreciate some feedback from someone that has experience with this type of machine, regarding this question... can one electronically adjust the vertical height to an accuracy of 1.0mm, 0.1mm, or 0.01mm? I note that the machine does have a 3-axes DRO, and would assume that the resolution would be something like 0.02mm or 0.05mm, but cannot see how an electrical motor and gears would be able to adjust to this accuracy given the momentum (lag) in any electro-mechanical device such as this.

The machine you showed the picture of does have a hand crank for fine adjustment of the table height, probably graduated in 0.001" increments or possibly 0.02mm, not sure about the metric as I've not run a metric mill but there will in any case be a fine manual adjustment. Once again, that machine will be capable of nearly everything a Bridgeport is capable of but also hogging off material with 3 hp on the horizontal spindle, the only downside I see is that it has only 2000 rpm on the vertical spindle but you say you're keeping the small mill so it's not that much of an issue. Personally, if all I was doing was hobby work I'd get a lighter, faster machine but it really depends on what you're planning on doing with it.
The universal machine would be my last choice simply because drilling with small drills would be a pain and I don't know of a way to put a power drawbar on the head, a machine with a sensitive/powered quill just makes things much easier.

 

[HennieL]

The machine you showed the picture of does have a hand crank for fine adjustment of the table height, probably graduated in 0.001" increments or possibly 0.02mm, not sure about the metric as I've not run a metric mill but there will in any case be a fine manual adjustment. Once again, that machine will be capable of nearly everything a Bridgeport is capable of but also hogging off material with 3 hp on the horizontal spindle, the only downside I see is that it has only 2000 rpm on the vertical spindle but you say you're keeping the small mill so it's not that much of an issue. Personally, if all I was doing was hobby work I'd get a lighter, faster machine but it really depends on what you're planning on doing with it.
The universal machine would be my last choice simply because drilling with small drills would be a pain and I don't know of a way to put a power drawbar on the head, a machine with a sensitive/powered quill just makes things much easier.

Thanks for this - given that the Bridgeport type of machine (with the horizontal spindle) is substantially cheaper than the universal head machine also pictured in my first post, and everyone's input that it would be more suitable to hobby-type work, this settles that debate for me.

Next problem - I've looked at two models of the vertical "Bridgeport type" mills from Knuth - the VHF1.1 pictured in my first post, and their model MF1P:

• The VHF1.1 has an ISO-40 spindle, a horizontal spindle, and a maximum vertical spindle speed of only 1660 RPM.
• The MF1 has an ISO-30 vertical spindle (and no horizontal spindle), and a vertical spindle speed of 4500 RPM

Now, given that one of my primary reasons for wanting to upgrade is to allow me to use carbide cutters for working on some difficult to machine steels, and knowing that these cutters must be operated at speed, what are your thoughts regarding the suitability and best "bang for the buck" of these two machines?

Man, it's @#$%^ hard to make the right choice if you don't know enough

 

[L98fiero]

Thanks for this - given that the Bridgeport type of machine (with the horizontal spindle) is substantially cheaper than the universal head machine also pictured in my first post, and everyone's input that it would be more suitable to hobby-type work, this settles that debate for me.

Next problem - I've looked at two models of the vertical "Bridgeport type" mills from Knuth - the VHF1.1 pictured in my first post, and their model MF1P:

• The VHF1.1 has an ISO-40 spindle, a horizontal spindle, and a maximum vertical spindle speed of only 1660 RPM.
• The MF1 has an ISO-30 vertical spindle (and no horizontal spindle), and a vertical spindle speed of 4500 RPM

Now, given that one of my primary reasons for wanting to upgrade is to allow me to use carbide cutters for working on some difficult to machine steels, and knowing that these cutters must be operated at speed, what are your thoughts regarding the suitability and best "bang for the buck" of these two machines?

Man, it's @#$%^ hard to make the right choice if you don't know enough

No experience with the ISO 30 taper but my understanding is that it's more rigid than R8, there are many tool holders available and it looks like a power drawbar is, if not standard, available, at 3 hp it will still do some serious milling. That machine looks pretty much in line with the capabilities of a Bridgeport because the head looks like a copy and as with all the other copies parts are probably interchangeable.

 

[SmithDoor]

If want to remove a lot metal fast a Horizontal Mill using the MT50 /ISO 50 taper .

Most of my production was on a #2 Horizontal mill. The Bridgeport just could not do job, just different in mill holders. The Bridgeport is more of Jig borer and drill than mill.

Dave

No experience with the ISO 30 taper but my understanding is that it's more rigid than R8, there are many tool holders available and it looks like a power drawbar is, if not standard, available, at 3 hp it will still do some serious milling. That machine looks pretty much in line with the capabilities of a Bridgeport because the head looks like a copy and as with all the other copies parts are probably interchangeable.

 

[SmithDoor]

I am working on a Horizontal mill Attachment for my small.
It reduces the speed too.
https://www.homemodelenginemachinist.com/threads/horizontal-mill-attachmen.33227/
Dave

No experience with the ISO 30 taper but my understanding is that it's more rigid than R8, there are many tool holders available and it looks like a power drawbar is, if not standard, available, at 3 hp it will still do some serious milling. That machine looks pretty much in line with the capabilities of a Bridgeport because the head looks like a copy and as with all the other copies parts are probably interchangeable.

 

[timo_gross]

I would agree that the BT30, same taper as ISO30 or NT30 is more rigid than R8.
BT40 is quite a bit larger.
Carbide cutters do not need to run at higher speeds, they are allowed to. Usually no harm done when running them "too" slow. You just cannot overdo it with chip load. Then the machine stalls, goes into error (better control) or brakes the cutter (better machine/small enough cutter)
A 6 mm (1/4 inch) endmill as per below table is sugested to run at 1400 rpm or 3000 rpm.
The table is for a mid level 4-flute carbide endmill, not particular special or expensive. I copied it from the tool catalogue.

High speed is only needed for the tiny ones. If the chip load is not maintained very accurate a 1.5 mm endmill breaks if you look angry at it ... i

It feels machine power is sometimes a poor indicator for what is going on in certain situations. For example a lot of CNC machines do not have a gear box. They need a massive big motor to deliver at least some torque at lower rpm. If slow cutting e.g. with a slitting saw or tapping with bigger taps is done. A much smaller motor with gear box can do the job as well.
A 0.75 hp gear motor can have more torque than a 2hp motor without reduction at lower speed.
I would think if you are into small stuff I would not get a mill with less than 4000 rpm.
At higher spindle rpm balanced tools are a good idea, not sure when to consider this.

Some manufacturers give you the motor power for 5 min overload, some give you the number for 15 min load, some use the number for 100% continuous running load. Then the same motor can come with three numbers in different advertisements.

Greetings Timo

 

[roncohudd]

Hi Hennie, power and precision come from mass, accuracy of manufacture - and heritage. Milling machines that of old have originated from lathes have as main a horizontal spindle, often like Bridgeport expanded with a versatile head with vertical spindle. The milling machines that originate from vertical drills and often come with a round pillar upright are much less sturdy. However these are often easier to operate. As my family in our former colonies has been guest of the Emperor of Japan we still prefer European manufacture over Asian manufacture.
So I myself have a Swiss Aciera F3 mill of about 600 kg. And a new German Wabeco F1210 mill of about 150 kg. The (only?) setback of the Aciera is that is has no quill. This means no feeling in drilling, feeding by moving the whole table up which causes quite some consumption of smaller drills. Therefore the German Wabeco with quill and high revs which is lighter but quite precise.
A friend of mine has a full size original Bridgeport which does boast a quill. And a slotting head.
So my advice is to get the biggest Bridgeport type you can afford, preferably an original.
Don't forget the revs you need for small hole drilling. I have a separate high rev milling/drilling head that I attach if I need to drill a lot of small holes in the same set-up as I did my milling.
And if there is a choice get the long table.

I just sold a Bridgeport style milling machine. 1980 JAPANESE MODEL. Very good machine. Much better than the Bridgeport that I still have.

The mill that does not have a quill, IMNSHO, is a bad choice for an amateur, I would thimpfk that belongs in a large shop. I too am looking at a mill that has both vertical and horizontal capabililties. I'm thimpfking the Grizzly

Grizzly G0757 - 9" x 39" 2 HP Horizontal/Vertical Mill
might be worth it.

Good machine. My Grizzly 13x 42 lathe has been great. Ran hard when I was in the business.

 

[HennieL]

Thanks everyone for your input so far - much appreciated.

I'm still waiting for a couple of quotes, but at this stage I think that I will be looking very seriously at the Knuth VHF1.1 with the ISO 40 taper.

Some manufacturers give you the motor power for 5 min overload, some give you the number for 15 min load, some use the number for 100% continuous running load. Then the same motor can come with three numbers in different advertisements.

Yes Timo, that's pretty standard - same as with music amplifiers, most cheaper manufacturers quote PMPO (peak music power output), whilst the top of the range guys quote RMS (root mean square) power to those discerning buyers that know better... Kids buy the 1000W PMPO units and think they're just great, but all they can do is make noise, not music

 

[larryg]

I would really appreciate some feedback from someone that has experience with this type of machine, regarding this question... can one electronically adjust the vertical height to an accuracy of 1.0mm, 0.1mm, or 0.01mm? I note that the machine does have a 3-axes DRO, and would assume that the resolution would be something like 0.02mm or 0.05mm, but cannot see how an electrical motor and gears would be able to adjust to this accuracy given the momentum (lag) in any electro-mechanical device such as this.

On The machine without the quill you do not rely on the mechanical/electronic feed to get accuracy. You use the hand crank to get the precision you need. At least that is how I do it on my horizontal mill with the universal head. All the feeds on my machine are gear driven and will drive to a mechanical limit. I have not tested the repeatability of the mechanical limit.

Now if the machine your looking at has a stepper motor on the z axis you MAY have the ability to send it to a set point.

lg
no neat sig line

 

[ytrose2]

Hennie, I am a South African now living in NZ. I have a mill which I bought in SA with a universal head (tilt and nod), but is too small for my workshop needs and difficult to get properly vertical on round columns. I have looked locally for a replacement, but we only seem to be able to get Asian machines here - very little from Europe. The message here is that Taiwanese stuff is better quality than Chinese.
Trying to get good tooling is difficult here in NZ. There is little demand. In SA (in the 90's) tooling was reasonably easy to get, much of it locally manufactured. Probably a spin-off from the arms industry. I see some SA tools here now (Gedore, FEW, etc.) and try support it.

 

[L98fiero]

I have looked locally for a replacement, but we only seem to be able to get Asian machines here - very little from Europe. The message here is that Taiwanese stuff is better quality than Chinese.

I can't speak for availability but the Chinese machines are about where the Taiwanese machines were in the 80s or early 90s, some are good but you have to be careful and research what other users think. In the mid-90s I bought several Bridgeport clones, they were quite solid accurate machines with chromed ways, the last time I saw them 7 or 8 years ago they were still doing good work so it kind of depends on which machine you buy. Back then Taiwan was producing some junk as well, to some extent, you get what you pay for, the better Chinese machines will cost more.
Having said that, about 10 years ago I bought a flat bed CNC lathe, it was the same machine as one of the Clausing machines, produced in the same factory but without the name, it was a disaster, pretty much anything that could go wrong did. My understanding was that the difference being that Clausing had an on site inspector at the factory, I think the machine I got was one that didn't pass the Clausing inspector or maybe any inspector but that's just an opinion from a pretty disappointed customer. The bad part was that I bought it through a well known industrial machine tool dealer so even that is no guarantee.

 

[willray]

I would really appreciate some feedback from someone that has experience with this type of machine, regarding this question... can one electronically adjust the vertical height to an accuracy of 1.0mm, 0.1mm, or 0.01mm?

I started life with an Ex-Cell-O variable-speed-head turret mill (Bridgeport style, only a bit chunkier), and have since acquired a few "real" mills, including a ram-type universal (Van Norman). I find that I use the Ex-Cell-O less and less for milling, and more and more, as a glorified drill press.

Precise adjustments in height on the (non-quill) universal are made with the knee, either with the crank, or under power, and (without a DRO) are as precise as you care to read the dial. Set the feed to 0.8 inches per minute, and stopping on any given target thousandth is not much of a problem.

Feeding into a setting on an indicator can be annoying, as you've got to be standing where you can manipulate the crank or the controls, and that's not always where you can read the indicator accurately. Conditional on being able to see the indicator, yes, at least with my mill, I can vertical-feed with the crank, to the accuracy I can read on the indicator.

If you think about it, this isn't terribly surprising. Vertical feed on the crank is, if I recall correctly .200 or .250 inches (been staring at Monarch dials too much recently). Call it .250, so about 6mm, in 360 degrees. With a crank handle that's some 12+ inches (300mm) in radius, so about 2 inches circumferential travel per 10 degrees. That's roughly 7 thou vertical feed per 2 inches of travel at the crank handle, or .17mm vertical feed per 5 cm travel at the handle. That's plenty of resolution to hit as much precision on the feed, as the rest of the mill and setup is likely capable of.

Power feeds on all three axes are glorious, especially with rapids for positioning and return passes. I find myself going to the machine that has them, way more often than going to the machine with the quill. Setups on the Ex-Cell-O may be a bit faster with the ability to fine-adjust the quill extension to perfectly dial in a depth, but once a part is fixtured and the mill zeroed (I don't have a DRO, just dials and indicators) the ability to just set the travel stops, slap the table drive into feed, and let the machine worry about the cut, really becomes addicting.

That being said, and this brands me a rank amateur, I still don't feel comfortable plunge-cutting with the power fed knee. I am much more comfortable if I can "feel" the cut on a plunge, so I reflexively go to the Ex-Cell-O and its quill, if I've got to push a cut vertically. Academically, I know I can just look up the recommended inches-per-revolution for the cutter, set the speed and feed appropriately and let the vertical drive handle the cut better than I can "feel" it, but there is something that still just freaks me out about doing that.

Still, if I could only have one, the Van Norman would stay and the Ex-Cell-O would go. I could get over my trepidation about plunging with knee, and while setups might be a shade slower, I can produce better, more consistent work with the Van Norman than with the Ex-Cell-O.

Will

 

[awake]

So much already covered above, but I wonder if it is helpful to state the obvious: any mill is a tradeoff between flexibility and rigidity. Yeah, that sounds like a bad joke, but it isn't. The more you want one mill to be able to do - sensitive drilling, angled milling, high speed milling, etc. - the more compromises you have to make. The genius of the Bridgeport design is that it is eminently flexible - tilt, nod, quill and knee, ram in or out, ability to add various attachments for right angle, rotary, etc. The pain and frustration of the Bridgeport design ... is that it is eminently flexible, as in, not nearly as rigid. So if you want or need the flexibility, you pay for it by taking reduced cuts. If you want to hog off metal, you need rigidity, and you pay for it by not having as much versatility.

I would dare say that with clever setups and care, you can accomplish many things that might be outside the normal envelope of either a more rigid machine or a more versatile machine - it just may take more time and care to accomplish. And keep in mind that all things are relative - a BP, which some machinists describe as being as rigid as a wet noodle (because their needs are for hogging off lots of metal quickly), is at least one if not several orders of magnitude more rigid than the "Big Red" mill drill that I started with. I did a lot of good work on the Big Red, including some things that apparently I wasn't supposed to be able to do (!), and I still have the Big Red ... but I haven't used it at all since I got a BP. The only advantage the Big Red has over the BP is ability to fit into a smaller space and to be moved with relative ease - which may be the deciding factors for many of us, and may outweigh (bad pun intended) the far greater rigidity and flexibility of the BP. It's all relative ...

 

[methuselah1]

Bridgeports are whippy. Very versatile, but not as rigid as a Deckel. The FP series was originated in 1917, then copied by at least seven other companies! The are plenty of this pattern out there, and by the time you have the vertical, and high speed vertical heads, and a slotting attachment, you're set for life. My one had an MT4 collet adaptor in the vertical head, the high speed head used U2 collets, I forget what the horizontal taper was. My dividing head was by Thiel, and used collets with a 40 INT. adaptor. That seems to have become the industry standard for this size of machine. 50 INT. is unusual now, 30 INT. is still quite easy to pick up in the U.K.

A good gauge of machine quality is when the manual states you have to warm the quill up for half an hour before you start work. So it was with my Alexander! Slip platforms are another give-away.

I could have wept when I had to sell the Alex, shucks, I think I DID weep; but my subsequent BP copy is adequate if I don't want to hoof it. It just isn't in the same class.

 

[Richard Hed]

Bridgeports are whippy. Very versatile, but not as rigid as a Deckel. The FP series was originated in 1917, then copied by at least seven other companies! The are plenty of this pattern out there, and by the time you have the vertical, and high speed vertical heads, and a slotting attachment, you're set for life. My one had an MT4 collet adaptor in the vertical head, the high speed head used U2 collets, I forget what the horizontal taper was. My dividing head was by Thiel, and used collets with a 40 INT. adaptor. That seems to have become the industry standard for this size of machine. 50 INT. is unusual now, 30 INT. is still quite easy to pick up in the U.K.

A good gauge of machine quality is when the manual states you have to warm the quill up for half an hour before you start work. So it was with my Alexander! Slip platforms are another give-away.

I could have wept when I had to sell the Alex, shucks, I think I DID weep; but my subsequent BP copy is adequate if I don't want to hoof it. It just isn't in the same class.

Most of us on this forum are not doing this work for customers (some are) but rather for amateur reasons, building models. So BP style mills are better for us. I certainly would not want the type of herky machines you are talking about in my small shop--had I lots of room and lots of moolah, I would want several types of machines, but I am just making steam engine models and maybe a bit of designing in a garage shop.