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Seeking high-precision milling machine for mild steel, better than Proxxon MF70(!)

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  • #91
    Originally posted by ship69 View Post
    what actually goes wrong?
    You destroy your tools in short order, create completely useless parts, you ignore the "high-precision" specification that you yourself outlined

    If you want to settle for a piece of metal that looks like its been through a blender, is dimensionally accurate to +-.1", and wastes a lot of money to make, get a hacksaw and light a $20 bill on fire. What people are repeatedly trying to tell you, and youre subsequently ignoring, is that the needs youve outlined do not fit the tool you want. If youre willing to sacrifice accuracy, you dont need a mill, end of story. If you think youre somehow going to get anything approaching accuracy from a $300 toy spinning a 4mm end mill, then put frankly youre off your rocker.

    Youve got the best answers youre going to get, no matter how much you complain about aesthetics, worthless a complaint as that is, the facts wont change. If you cant compromise on weight, get a sherline or taig. If you cant compromise on price, get the proxxon. If youve decided that accuracy and precision are the things you want to compromise on, get a hacksaw

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    • #92
      Originally posted by epicfail48 View Post

      You destroy your tools in short order, create completely useless parts, you ignore the "high-precision" specification that you yourself outlined
      ........... If you think youre somehow going to get anything approaching accuracy from a $300 toy spinning a 4mm end mill, then put frankly youre off your rocker.

      Youve got the best answers youre going to get, no matter how much you complain about aesthetics, worthless a complaint as that is, the facts wont change. If you cant compromise on weight, get a sherline or taig. If you cant compromise on price, get the proxxon............
      That seems like an overly "blanket" condemnation.

      Anything calling itself a "mill" should not have a problem with a 4mm end mill (that's 0.157", smaller than 3/16"). You may not be able to feed it fast, but it should cut most normal materials fine, including some types of stainless.

      That being the case, "accuracy" should be pretty much dependent on how you operate the mill. A full depth cut to final dimensions? Maybe not a great idea.

      With light weight and lower power come the need to take smaller cuts. This is both from a power standpoint, as well as from the standpoint of machine flexibility and the ability to have the cut be "where you want", rather than "wherever the cutter gets forced to".

      If you accept that, and do take the smaller cuts, working WITH the machine and not working against it by trying to force it to be what it is not, you should be able to get decent results. Ther will be some level that cannot be achieved, but that is true of ALL machines, they have limits.

      ANY machine that has been named so far, can produce good, accurate, results. That includes the hacksaw and file method.... Where they differ is in how easy it is to get what is wanted.

      I would wager that many people here can use any of the machines to "accurately" produce any part that fits on the machine, "can" be made on the machine type, and is made of reasonably standard materials (not hardened steel, etc). I will NOT claim it would always be easy, fast, etc, nor that they should be able to hold tenths of a thou.

      I have worked with some crappy lightweight machines. It's a real pain to get anything done, but it can be done, it usually just takes a lot longer.
      2801 3147 6749 8779 4900 4900 4900

      Keep eye on ball.
      Hashim Khan


      It's just a box of rain, I don't know who put it there.

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      • #93
        You are a delight Tears.

        Comment


        • #94
          Ship69, you asked earlier about options if you lowered your need for accuracy. Well, given that you want to run some very small drills and end mills which I suspect you will want to be carbide types the need for accuracy and accurate running spindle is going to be pretty high.

          Keep in mind too that Small Planes mentioned a .003" ( .076mm) runout in his PF70. And how it caused the smaller size tools to snap off regularly. So regardless of any other machine specifics to run carbide tooling the spindle needs to be something that has very low runout and which has good bearings that hold that runout.

          Plus this means a spindle that takes collets. And it means good accurate collets as well since cheap collets can be a nasty source of runout too. I would not be surprised if Small Planes' issue was not related to poor collet quality either. The style of collets shown in the MF70 video you linked to about 10 posts back showed the Dremel and similar style collets which are not always that great.

          And like you seeing all the shoddy plastic in the control paths and the use of anodized aluminium put me off strongly. It would be fine on a tool used for milling wood, plastics and some limited amount of non ferrous metals. But you're talking about mild and stainless steel. the fine swarf that would get into the ways would cut into the aluminium in short order.


          Looking at a couple of videos on YT for the BFW40 I'm thinking that it's a big step up from the PF70. And the video linked here shows the motor doesn't sound too raspy or loud.

          (38) Proxxon BFW 40/E spindle + BFB 2000 stand - presentation - YouTube

          But at right around the 6 minute mark he puts a tool in one of the collets and tests the runout. At around 15mm from the nose of the spindle the dial gauge is showing 0.19mm of runout. That's .007 inch and twice what Small Planes had which already snapped off the small size carbide drills. So it looks like that's not an option either. Or it would require better collets. But that won't help if Proxxon uses a proprietary collet design.

          The FF230 looks like it might be a little better. But there's not much on YT about it. If you're not in too much of a rush this guy might get a few more videos out fairly soon and perhaps one of them will have more on the spindle accuracy. At least with the 230 the table and lower look like they are cast iron. That's a big step up the food chain. And at 40 odd lbs still easily movable.

          (38) Look-See: Proxxon FF230 Micro Mill Part 1 - YouTube

          Chilliwack BC, Canada

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          • #95
            Originally posted by Bented View Post
            You are a delight Tears.
            Glad to make you happy, Ed.

            I figured you for a person who could get good work out of a crummy tool. I did not suppose you would enjoy it, but you could do it.
            2801 3147 6749 8779 4900 4900 4900

            Keep eye on ball.
            Hashim Khan


            It's just a box of rain, I don't know who put it there.

            Comment


            • #96
              I have to ask what your experience level is. Often times a relatively new user or a user going into a relatively new area can pigeonhole themselves into things that are either not practical, or that other much more experienced general users may not have the specific knowledge of. When I was starting out in aluminum mold cutting I butted my head up against both of those things many times. Finally somebody told me, " Bob, you may just be the expert in what you are trying to do. You're going to have to try some things and determine what actually produces best for the types of operations you are doing." Their comments weren't exactly accurate, but they really helped me to understand that I didn't need to focus on just what I wanted to do but on whether it was possible to do it using the constraints that I pigeon holed myself into.

              You do not need much horsepower if you're using a very small mills. Generally with small mills RPM is your limiting factor for production rate. If you use some slightly larger small mills rigidity may also be a factor. Backlash of course is always a factor. Even if you don't need much accuracy backlash can cause you other issues. My big trap though was a resistance to using water soluble flood coolant. I spent a great deal of time trying just about every other stopgap measure short of that. When I finally broke out that distilled water and a decent high quality industrial soluble coolant and not that Kool Mist crap almost all of my problems went away.

              What I think you need to do in my opinion is step back and reevaluate all your basic assumptions. Determine if their pigeonhole traps or if they are really serious necessary constraints.

              Of course you can gain a great deal from the knowledge of those on this group, but you also have to take a step back and remember guys like John Saunders from NYC CNC aka Saunders Machine Works started out making parts on a Taig Mill in a New York City apartment. Everything on your wish list may not be possible, but it may be possible for you to get those things that you need for your circumstances and your application if you approach them with the right attitude.
              *** I always wanted a welding stinger that looked like the north end of a south bound chicken. Often my welds look like somebody pointed the wrong end of a chicken at the joint and squeezed until something came out. Might as well look the part.

              Comment


              • #97
                let me know when you find one, and i'll order three to stick in my garage
                -paul

                Comment


                • #98
                  Rich C -
                  You are probably correct but this page talks about a "Mill head"
                  http://www.servoproductsco.com/html/...mill_head.html

                  Good to hear that I don't need 10,000 rpm to do 0.55mm drilling.
                  Presumably the spindle's runout is pretty important though at that size, yes?

                  Everyone keeps talking about accuracty, but I knowing that I need to compromise somewhere, I don't really care about accuracy.

                  Everything is pointing to Sherline except for the lack of quill.


                  @BCRide - yes, that is an extremely interesting video about 'sensitive drill holders'. That said, he was using a lathe not a milling machine. In order to use on a MILL it sounds like you need to spend $699+ for a name brand version, (maybe $150-200 for a cheap one) on a "micro drill chuck adapter" / (AKA "floating chuck" / "spring-loaded chuck") with a ball-bearing race-type of collar, so that the chuck will spin but the collar can be kept stationary, so that you can feed by hand rather than by using the quill handle. Btw, where does he mention the RPM?



                  epicfail48 -
                  > you ignore the "high-precision" specification that you yourself outlined
                  Like I have previously stated, what I meant by "high precision" was the ability to make fine cuts when required. I am not worried about inaccuracies when making larger cuts.

                  > If youve decided that accuracy and precision are the things you want
                  > to compromise on, get a hacksaw
                  Many types of cut can't be made with a hacksaw. Not helpful.


                  @JTiers & @BCRider
                  Yes, the runout seems to be THE critical issue if I intend to work at small scale.


                  bob La Londe
                  My experience of workshops in general is good. As I have said throughout this thread, my experience of milling is zero.

                  > You do not need much horsepower if you're using a very small mills.
                  Yes. I was only shooting for larger horsepower in case I wanted to mill slighly large diametres of mild steel, but I do get that rigidity of the whole setup becomes a problem. It's just that the torque of my 100w hand drill is frankly pathetic. And e.g. when I tried cutting with a grinding disk it is painfully slow.

                  > Generally with small mills RPM is your limiting factor for production rate.
                  What RPM are you proposing that I shoot for? 5,000 RPM? 10,000 RPM? More?



                  MY THINKING SO FAR

                  Standing back from the issues raised, I now think that maybe 5,000 RPM would be fast enough.
                  That brings a lot more machines into play.

                  HOWEVER even if I raise my budget to say GBP1500, and weight limited to 36Kg, the lack of quill on the Sherline & Taigs remains problem for drilling.

                  Proxxons seem to have terrible build quality in terms of runout.
                  And nobody seems to make small/compact/light machines (that are easy to lift and put away overnight) but with a better build quality.

                  Maybe the whole idea of a mill that sits on your desk that can mill mild steel, that can be easily put way over night, just ISN'T POSSIBLE.


                  FURTHER THOUGHTS

                  - What about very much more expensive machines, bought second-hand?
                  e.g. someone has suggested Aciera f1 & Sixis but they seem to be heavy (as well as eye-wateringly expensive).

                  - Or what about buying a small Proxxon and paying someone to upgrade their bearings?
                  At least I'd get a quill!

                  - What do watchmakers use? (Do they user huge machines? Or smallish mills like Sherlines?)

                  - what about vintage machines (given that the technology of milling seems very mature)

                  - Anyone know much about Hager or Henri Hauser milling machines?


                  J


                  PS It seems a shame that nobody seems to have built "feel" feedback (e.g. some sort of acoustic feedback to report changes in torque and/or Z-force to the human operator) into any of these larger machines. But I'm getting ahead of myself.


                  Comment


                  • #99
                    Well RPM is sometimes a compromise about price depending on what you are milling and the size of the Mills you are using. For example my fastest machines both have 24,000 RPM spindles. I use them at 24,000 RPM almost all of the time. I could use a 40,000 or even a 60,000 RPM spindle for certain operations and be faster and more efficient. So trying to again pigeonhole trap yourself into a specific RPM is not necessarily the best way to look at it. You may have to look at Price versus RPM versus how you're going to use the machine. There was no way I was going to get into reading 7 pages of back and forth. When it comes to milling you are a beginner. As you said in your previous message. You have to look at it from the perspective of "I am a beginner.". Regardless of your experience with other types of shop operations. I have the same issue with ego when I'm learning something new versus I have a lot of experience too. If your goal is to be able to Mill mild steel then you can do that with just about any garbage small desktop import machine. It can hack a piece of metal off another piece of metal. If you want to mill mild steel efficiently which by the way doesn't mill as well as some other steels do you may want to look at something a little better.

                    You can use an inadequate machine to do a job if you work within this constraints of the machine. Then for your purposes maybe the machine is not inadequate. You take lighter cuts and slower feeds within the capability of the machine to maintain its shape and the horsepower and RPM to remove material.

                    If you're looking for a magic chart that you can plug into for everything you want, as far as I know it doesn't exist.
                    *** I always wanted a welding stinger that looked like the north end of a south bound chicken. Often my welds look like somebody pointed the wrong end of a chicken at the joint and squeezed until something came out. Might as well look the part.

                    Comment


                    • Bob La Londe - out of interest what are your machines that can do 24,000 rpm? I have yet to see any in my travels.

                      Comment


                      • Many mills have very high rpm spindles.
                        Speed with power and rigidity gives the ability to shift metal rapidly.
                        Many hobby cnc mills are 20k+ rpm
                        https://shop.carbide3d.com/products/...32912906321981
                        https://www.bantamtools.com/cnc-mill...-machine-specs
                        Most are outside your budget so no one has mentioned them

                        Just south of Sudspumpwater UK

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                        • High spindle speeds on none tiny cutters requires fast feeds to give correct chipload. Manual handles can’t keep up. So mostly high speed spindle = CNC for anything of any size.
                          Just south of Sudspumpwater UK

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                          • Originally posted by ship69 View Post
                            Bob La Londe - out of interest what are your machines that can do 24,000 rpm? I have yet to see any in my travels.
                            Have you actually seen or demoed any of the small mills? Talked with the dealers or customers the dealer sold to?

                            Comment


                            • Originally posted by ship69 View Post



                              I don't really care about accuracy.


                              Now you are nearly there in your search.
                              Right where you started
                              Last edited by Bented; 04-08-2021, 06:15 PM.

                              Comment


                              • Originally posted by ship69 View Post

                                - What about very much more expensive machines, bought second-hand?
                                e.g. someone has suggested Aciera f1 & Sixis but they seem to be heavy (as well as eye-wateringly expensive).

                                - Or what about buying a small Proxxon and paying someone to upgrade their bearings?
                                At least I'd get a quill!

                                - What do watchmakers use? (Do they user huge machines? Or smallish mills like Sherlines?)

                                - what about vintage machines (given that the technology of milling seems very mature)

                                - Anyone know much about Hager or Henri Hauser milling machines?
                                They don't meet your criteria, price or weight. I've got an F1 and a Hauser M1, I have to take them apart to carry them. The Swiss know what building quality means, however as you say they eye wateringly expensive....and that is the used prices. Neither are made anymore. A bit of tooling can be $1000 or more. But they sure are well made and precise machines.

                                Few watchmakers would mill anything. I'd bet not 1 in 1000 actually watchmakers would have a mill. There's the odd hobbyist like me into machining and dabbling in watches who might and theres a handful of dedicated hobbyists making his own watch from scratch who would. There's they few like Roger Smith at the top of food chain selling watches for 100's of thousand who do make their own parts... but the 1000's of trained watchmakers you'd take your your watch to none are likely to have a mill. The watchmaking trade isn't what you're thinking it is; there is very little machining except for the odd balance staff. Mostly its repair and servicing (which is plenty challenging on its own)

                                Where you are going to see the most use, and highly skill use, of these little mills is with the model engineering fraternity. What they'd have to say has imo been covered
                                Last edited by Mcgyver; 04-08-2021, 09:07 PM.
                                in Toronto Ontario - where are you?

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