advice/opinions on a new x45 clone

[John Evans]

Time you are done screwing around to make one of these do what you want you still have a compromise ! Buy a Bridgeport type mill and you will get all the features you want. I see it all the time at my tool dealer friends shop ,people wanting to trade in/upgrade to a BP style mill. Tom won't take in drill mills in trade as they are worth little in resale . Got 2 now that he gave very little for and they have been sitting for months-no interest in them.

[pete]

All the VFD does is control the motor, There's multiple types. Even 3 ph VFD''s when you already have 3 ph at the location. Those VFD's are used to do the motor control. Soft start, pre programmed speeds, variable speeds etc. The most common type for home shops would probably be the ones that take your exsisting single ph power and turn it into the same voltage but in a 3 ph form.You then get all the other options for control that decent VFD's are built with. Nothing other than the drive motor is controlled by the VFD. Just be aware that the geared head mills are almost always noiser than the same machine would be with a belt drive. The gears give you your major speed changes and are quick to make those changes. Sometimes you have to rock the spindle back and forth a bit to get the two gears to drop into engagement. Each spindle speed that each gear position gives can be fine tuned with the VFD controlling the motor.

Belt driven mills other than the variable speed ones are a bit slower to change, but the same thing happens. Each belt position gives you a speed ratio between the motor and the spindle. And you do the same thing for adjusting the speed with the VFD. But there's less moving of the belts because you can adjust up or down on the motor speed. If a mill has a back gear, (Bridgeport type) then shifting into that back gear changes the spindle rotation to the opposite direction. So that requires a VFD that can provide reverse so you then have the correct rotation of the spindle for your cutting tools. I don't know if all VFD's built today now have reverse automaticaly built in or not. When I bought mine the dealer asked if I needed one that could reverse the motor. I knew just enough then to know I'd need that.

The mine I worked at had pretty much unlimited 3 ph power coming into the site. After stepping down the incoming voltage almost every motor in the ore concentrator had either a VFD or a Progressive Logic Controller (PLC) simply because it allows that fine tuning of the motor speed and other options. There were hundreds of motors in that plant and most were a great deal larger than anything we'd use, so it's a huge expense to buy and hook all that up. They still do it because of the control over the motor they give. It makes setting up a complex plant much easier. But what we want is a VFD.And most times it's to get that 3 ph the motor requires.Everything else a VFD can do are just really nice to have options. As I mentioned 3 ph motors are much smoother to operate and for my mill and what I've seen much quieter in operation.

With motors that don't have additional cooling fans and only the single motor shaft driven fans, then the cooling is directly related to the speed of rotation of the motor. Running one for too long at too low of a speed can over heat the motor. Most times it's not an issue, but it is something to be aware of. Mine hasn't been changed yet, but 3 ph motors work even better on a lathe because of that smooth motor rotation. It can have a major effect on the surface finish you can get between using an AC motor and one with a 3 ph. It does show up to a lesser amount with a mill.

There are other ways of getting single ph power converted to 3 ph, but for a machine that only has a single 3 ph motor then the VFD is probably the best way to go. For a whole shop full of machines then something like a rotary phase converter might be the more cost effective method. But you would then lose the variable speeds etc that the VFD's give.

[pete]

I did a bit of thinking so fwiw and just to add a few/many points about that guy claiming to be able to make head moves at 2/10ths accuracy. And yes I do know you said "he claims". Now I'm not gonna say it's impossible since I haven't seen his set up. But lemme see if I can figure this out. He's using a chain drive so there's those sprockets and the chain, then the 90 degree gear box, shafting, and a hand wheel at the minimum. And he claims he can make head moves to surface grinder accuracy? I wonder how he's measuring that? My 10ths reading dti's are pretty good quality, but there only guaranted to + - one count. So that's 2/10ths right there in uncertainty. They will do better than that because I've checked, but that's what Mitutoyo will point out is the allowable tollerance range and still be within there specifications. My dro could measure it maybe, but I couldn't be 100% sure which exact area of an inch over it's travel it's moving that 2/10ths unless my shop was at a stable 68 degrees that the factory calibrates them at. It could be laser mapped as a check against the table travels I guess, I'm a little too cheap to have that done. But with the equipment I do have I still can't be sure the dro is that accurate without testing and verification with certified gage blocks that can be trusted and be traced back to NIST. And after all that I still wouldn't bet my life on the numbers being 100% right. I've got a Mayr supermess indicator that can do 20 millionths, but again I'd need that 68 degrees, and then for moves more than it's 3 thou range I'd have to use something like my gage blocks as well. Again they need that tiny little 68 degree problem solved or know the exact temperature and the blocks deviation from being correct and calculate what the difference should be. To lower that uncertainty problem to an acceptable level then an industry standard is to use measuring equipment that's at least 10 times more accurate than what your measuring to so you can be semi confident in the results. But to do that to those levels the parts and metrolgy equipment to be measured and measured with are temperature stabilised in a 68 degree + - 1 degree or better in a dust free filtered air metrology lab for at least 24 hrs or more depending on the part mass. But maybe I'm wrong and he does have that RF 45 in one of those in his basement. And one further point, resolution or just how many numbers are shown to the right of the decimal place is a whole lot different than any measuring tools repeatable accuracy is.Resolution has nothing to do with how accurate a measuring tool is. Those are two completely seperate items and the terms ain't interchangable.It could be accurate to + - .100" and still have 5 zero's to the right just to impress people.

There's a great many claims out in the wilds of the internet. I don't blindly trust anything unless I've tried to educate myself as well as possible about it using trusted sources. As an example, Long Island Indicator Repair and the web site they maintain.Both Mitutoyo and Starrett have free infomation on there sites as well.There's also a huge amount about machining shown by very highly skilled professional or even hobbiest level people on Youtube that I trust the information there showing 99.9%. But there's also a few who seem to think a video camera and a couple months twirling the hand wheels around somehow makes them an expert since there showing me and everyone else how it's supposed to be done. When I started this minor level of insanity there was no internet, and any information had to be gotten through books since I didn't know anyone else into metal work. Now that I think about it I even had to figure out what books I should buy, then find out where I could get them. Now we do have the forums, Youtube, Google searches etc. They all can be an excellent addition to those books that I'm still buying today. All of that still doesn't make me an expert by anyones definition, not even close and it never will. I still make mistakes about information I thought I knew or don't fully understand. But imo all those information sources can help to teach people enough to seperate out the ones who have a clue from the one's that don't. So I guess that's my rant done for today.

[John Evans]

And one further point VFD's only work with 3 phase motors. Does the mill-drill referenced here have a 3 phase motor or the option for one?

[defed]

i am somewhat familiar w/ VFDs and how they work, i only asked about changing to belt drive due to the noise and gears being potentially unnecessary for speed control/changes. suppose that depends on the motor and pulley ratio, seems you still need more than 1 ratio.

as far as his .0002" claims, i find it hard to believe too, but i do believe that his set up has the ability for a bit more/finer control of the head movement than the standard crank.

[spro]

The word is "overwhelmed" . It is what it is and quite useful machine. Somewhere between the brutal honesty of JE and intricate explanations by Pete, there is a machine there. It isn't to be the first and last of your experiences with a vertical mill.

[defed]

Tom won't take in drill mills in trade as they are worth little in resale . Got 2 now that he gave very little for and they have been sitting for months-no interest in them.

i'll give him $100 for the pair.

[Glenn Brooks]

Three things I would definitely do right up front, (if I were buying a new mill - even a used one-) is:
1) add a nice DRO
2) definitely add power feed to the table,
3) buy more than you need

The DRO will improve your productivity and enable greater accuracy. Simple DRO functions like drilling holes evenly spaced around a circle are worth their weight in gold. Sort of like switching to lattes when all you had before was boiled coffee. (Sorry I live in the Seattle area - heart of latte-land ). If you can afford it, don't skimp on low end units. Just buy a decent mid range unit with three axises and it will vastly improve your set up capability and parts making ability.

Also, I lost my table feed on my mill when my elderly gear driven power assist imploded through old age. The company is long gone and It's really been a handicap not to be able to power up the table. (Somewhere down deep in my winter list is a task to learn how to make a new drive gear and put the power feed back in operation.) Really makes a difference when you can set power feed speeds and watch those nice, shiney uniform surfaces emerge out of cold rolled scale. Can't speak to power down feed as have never used it... But sounds nice to have - although a lot of people say it's better to "feel" the boring tool or drill work its way down through the part by working by hand.

(3) Generally speaking, many people have told me I think I have learned - it is better to buy a more capable machine than you initially think you need. Reason is, your skill level will go up rather quickly, and likely you will soon envision taking on bigger and more interesting projects. If you buy a basic, 'small' machine - you may out grow it rather quickly, say within a year. Then find it hard and expensive to upgrade. For a little more machine, you could have a mill that will be fully capable of supporting your long term interest and growth as a machinist for many years into the future.

Best wishes shopping!

Glenn B.

[Harold_V]

- although a lot of people say it's better to "feel" the boring tool or drill work its way down through the part by working by hand.

I'd suggest you avoid the opinions of such people, although only when boring.

A couple things to consider.

The rate of feed plays an important role in size, so if you're trying to create a precision bore, feed rate, alone, can offer serious deviations, to say nothing of the guaranteed inferior surface finish. Power feed for boring borders on being a necessity---it isn't really an optional choice.
And, yes, you can hand crank or lever feed via the handle. Just don't expect much in the way of consistency.

Drilling? Totally different matter, especially on light duty machines like drop spindle mills. The quill power feed is NOT intended to be used for drilling, although they suggest it can be used for drills 3/8" in diameter and smaller. Anything larger offers the opportunity to damage the feed mechanism. It simply isn't robust enough to tolerate the generated forces.

If you haven't seen a drill being powered in an appropriate machine (like a radial drill press), it may not make much sense to you that power feed for drilling is of importance, especially in large diameter holes, where the operator can't overcome drill resistance. However, using a drop spindle mill for that purpose falls dreadfully below the requirements, including feed rate, to say nothing of the lack of power and rigidity.

Two feeds are quite desirable on small mills, one being the table (X), the other being the quill (Z). Saddle and knee are nice, but hardly a requirement.

Harold

[defed]

i was watching another video (yea, i know, i watch too many videos) of a guy who CNC'd a 45. he had the z axis running the whole head, which makes sense from a rigidity standpoint. not sure if he used a ballscrew on that as well, but it looked like it was really smooth and i presume able to move in small, controlled increments. one of my concerns about the 45s is depth control. i don't want to run w/ the spindle out 6" and i wasn't sure how well you could use the head itself, but it seems that it is doable to use it as you would a knee.

[Glenn Brooks]

Harold, what you say above makes total sense. I don't have any experience with large machines and appropriate feed rates for boring and drilling- only smallish, lightweight machines where hand feed is the only option. So never thought much about finish characteristics with hand feed. Now, just recently purchased a nice old Canedy- Otto camelback drill press with 24" table clearance and power down feeds. I've been apprehensive about how the power feed works, re: drilling large diameter holes for example + 1" holes. So from what you said, gives me more confidence to go learn how to use it properly. Thanks

Glenn

[Harold_V]

Happy to provide my comments, Glenn. Hope they prove to be useful for you.

If readers ever have the opportunity to watch a radial drill in action, especially with a large drill bit, I think they'll be favorably impressed. Imagine drilling large diameter holes without a pilot, and without effort. Fast, too. Feed rate borders on being unreasonable, yet the machine handles it in stride. They're an amazing machine!

Harold