Build Options? - Page 2


Page 2 of 2 FirstFirst 12
Results 13 to 19 of 19

Thread: Build Options?

  1. #13
    Registered
    Join Date
    May 2011
    Location
    Canada
    Posts
    593
    Downloads
    0
    Uploads
    0

    Default Re: Build Options?

    Quote Originally Posted by ger21 View Post
    You won't be cutting 1mm per pass with any of these machines.
    That's very true. 0.01" or less with a 1/2" very sharp carbide bit might get you some OK results. BUT, try to do a 3d carving using a ballnose bit, that's been previously rough cut and that's another can of worms.

    Quote Originally Posted by VanIsleDSM View Post

    There's also the option that I purchase this:

    Milling machine West Shore: Langford,Colwood,Metchosin,Highlands, Victoria

    I'm really not sure I want to deal with old equipment though, as well as the issue of whether I can even CNC that machine or not. I suppose you just remove the screws and replace with ball screws, add motors, mounts and electronics? I've never looked into converting a mill. Seems you could end up down a rabbit hole on that one. Does this machine look like a good candidate for conversion?
    Doing a conversion on that is 1000 times a better choice. I'm glad you're considering what I've said. As far as the conversion goes, it depends on how handy you are, what you design and build skill set is. Certainly a heck of alot easier than building an appropriate machine from scratch.

    The lead screws on that probably have alot of backlash. If so, you will be able to feel it when you turn the handles and then reverse the direction. You don't need ballscrews on a CNC machine necessarily. There may be a way to add an antibacklash nut made of nylon or something of that nature to the already existing leadscrews. The more difficult part will probably be the Z axis. Looks like you can adjust the vertical position of the head and use the quil (rotary handle) for the conversion. So find out how much movement you can get from just the quill.

    If you are apprehensive about the conversion, you could consider two alternative options. The first is to find a mill that has already been converted for sale. The second is to find a popular used mill that has a conversion kit readily available, and there are many of these. As for that model, I don't know, but you could do some searches with the model number to see if anyone has done a CNC conversion on one. Who knows, you might find a build log with a set of step by step instructions on how to do it. And there are many such build logs for different mills around.

    A quick search led me to this:

    http://www.cnczone.com/forums/bencht...342-cnc-3.html

    That looks pretty similar to the one you linked to.

    Working with older good equipment for you, sir, is a better choice. Just repaint it when you're done if you want it to look awesome.

    I wish someone had slapped me in the face and told me to do this when I was starting out. At this stage I'm building a custom machine to get the travels I need for the parts I want to make and have it mobile enough to move into the basement in sections. Do you have a garage? The machine will be heavy, you'll need some help to move it and preferably a garage to put it in if you buy it.

    Really, I would make any immediate decisions. Spend some time reading build logs and looking at videos and asking questions on here like you're doing, and the end results will be worth it. But at the end of the day, if you want to be happy cutting aluminum on a limited budget and time investment, your only good option is a mill conversion.



  2. #14
    Registered
    Join Date
    Mar 2008
    Location
    Canada
    Posts
    20
    Downloads
    0
    Uploads
    0

    Default Re: Build Options?

    I have an indoor shop. Not really any room left but I'll have to make some, I suppose I could relegate my current drill press to the back room. My shop is up a flight of stairs, but I did already wrestle a Clausing 12x36 lathe into there with some help, so I'm sure the mill would be manageable. I'm not too worried about my skills approaching the matter, just not familiar with the topology of the machine and if it's "CNC-able" without a huge amount of fabrication and modification. I am familiar with smaller scale CAM from building a 3D printer. Electronics is my main game, so I'm really looking forward to doing the motors, drivers, and sensors.

    The conversion you found and posted does appear to be a different rendition of the same tool. Seems to be common with what I suspect to be a Chinese machine, rebranded by different importers and changed slightly. I also have a 7x14 Chinese mini lathe. It's actually really nice for working on smaller parts and I use it instead of the Clausing a lot of the time. I wouldn't be adverse to trying another Chinese machine. Thanks for finding this. It gives me confidence to get this machine, knowing it can be done.

    The only thing I'm a bit worried about are the gibs on a machine like that. How often are you having to adjust them with a CNC mill? Probably a lot more often than a manual. I'd think the linear rail bearing would be much better in this regard than some old ways and gibs, but I dunno, maybe I'm wrong.

    Nice thing going this route, is that I can manually mill the parts I need for the conversion. I currently have a milling attachment for my Clausing, but there's not a lot of travel.

    Either way, I'm gonna go check out the machine. I suppose I should just treat it like buying my old Clausing? Poke around with the dial indicator and make a few cuts with it? Anything specific to check for a mill as compared to a lathe? I suppose I could google these things.. just kinda rambling on here now.



  3. #15
    Registered
    Join Date
    May 2011
    Location
    Canada
    Posts
    593
    Downloads
    0
    Uploads
    0

    Default Re: Build Options?

    Quote Originally Posted by VanIsleDSM View Post
    The only thing I'm a bit worried about are the gibs on a machine like that. How often are you having to adjust them with a CNC mill? Probably a lot more often than a manual. I'd think the linear rail bearing would be much better in this regard than some old ways and gibs, but I dunno, maybe I'm wrong.
    Good quality linear rails (square type) are better but also really expensive. Compared to V groove bearings or round type rails, personally I'd much rather prefer the gibs. I doubt you have to adjust them too often. Lots of people have done CNC conversions on mills and kept the gibs, seems to work fine for them.

    Quote Originally Posted by VanIsleDSM View Post
    Nice thing going this route, is that I can manually mill the parts I need for the conversion. I currently have a milling attachment for my Clausing, but there's not a lot of travel.

    Either way, I'm gonna go check out the machine. I suppose I should just treat it like buying my old Clausing? Poke around with the dial indicator and make a few cuts with it? Anything specific to check for a mill as compared to a lathe? I suppose I could google these things.. just kinda rambling on here now.
    There will be no comparison between the ability to cut aluminum and copper between a rigid mill running at 220V (even 110V) and the machine you were first considering. At the end of the day a mill is a vastly better choice. I have heard that the Z axis can be the most tricky. In the build log i posted a link to, I think he used a pneumatic cylinder to take out any slop in the quill.

    A dial indicator and a few cuts seems like a good place to start.

    Beyond that, hopefully one of the members here, and there are lots of them, who have experience with different mills can advise you on what to look for and what kind of mills make good conversions.

    If you can figure a way to use the existing lead screws by adding an anti backlash nut, then really all you have to do is add some motors and pulleys. Have you looked to see if there is a kit available for this, I honestly don't know if there is one.

    The other option would be a mini mill with an upgraded spindle motor, from a treadmill or something like that. I've seen a few videos of them cutting aluminum like a boss.



  4. #16
    Registered
    Join Date
    Mar 2008
    Location
    Canada
    Posts
    20
    Downloads
    0
    Uploads
    0

    Default Re: Build Options?

    Depth of cut will be better for sure, but it looks like the spindle maxes out at 2500 RPM. Seems that would create a bottleneck in cutting speed. Maybe I could eventually replace the motor with a VFD or something, to get more RPM? Will the spindle bearing have an RPM limit? Maybe we're getting into new thread territory about this specific mill now.

    This video was helpful for me to see everything I would to do to CNC the machine.



    I would like to use ballscrews, the Chinese ones are such a good deal, why wouldn't you? The only thing I'm not terribly confident about is dealing with the bearings on the ends of the ball screw to eliminate any backlash. I really don't know how best to go about that. I found a thread talking about a system with angular thrust bearings, but the pictures were broken, so it's hard to tell what's going.on.

    Making some motor mounts and an adapter to mount the ball nuts seems pretty straight forward. Hopefully I can just get some ball screws custom machined from ebay, heard others talking about that. Maybe copy someone else's spec for the ball screws and their bearing design, because I'm out of my element on that.

    Seems the quill isn't the best Z axis, but it can be made to work. With 5" of travel, people were complaining about switching from drills to end mills, having to raise the head and re-center. Does seem like a bit of a pain in the ass, but do you really bother with drills once you have CNC? Just let the end mill make a hole whatever size you want, no? I usually use mechanic drills anyway, a little shorter, and more rigid.

    Last edited by VanIsleDSM; 09-09-2017 at 07:50 PM.


  5. #17
    Registered
    Join Date
    May 2011
    Location
    Canada
    Posts
    593
    Downloads
    0
    Uploads
    0

    Default Re: Build Options?

    Quote Originally Posted by VanIsleDSM View Post
    Depth of cut will be better for sure, but it looks like the spindle maxes out at 2500 RPM.


    Yes, you'll want more speed. I've been trying for the past half an hour to find a video on youtube, where the guy replaced his spindle motor on a small mill with one that had more power, we're talking perhaps 2HP range, and he was cutting very fast using a three flute bit. One of my favorite videos. I can't find it. Perhaps it got removed. It's several years old.

    Quote Originally Posted by VanIsleDSM View Post
    Seems that would create a bottleneck in cutting speed. Maybe I could eventually replace the motor with a VFD or something, to get more RPM? Will the spindle bearing have an RPM limit? Maybe we're getting into new thread territory about this specific mill now.
    I couldn't advise you on the bearing limit for that mill. That's why you need at least a build log to follow from someone who has done a conversion previously on that type of mill. There are different types of induction motors. Some are designed to be run at variable speeds. Some are designed differently. You'd need to figure this out before adding a VFD to an existing motor. I know many people upgrade to larger motors on small mills. I'm thinking they are getting around 6000 to 7000 RPM after upgrade. BUT, you have to check for the specific mill, I'm just talking generally.

    Yes, perhaps it is time for a new thread. You could call it "Help me choose which mill to buy for a CNC conversion". Lots of people here can give better advice than me. Some, people on here even sell the conversion kits.

    Quote Originally Posted by VanIsleDSM View Post

    I would like to use ballscrews, the Chinese ones are such a good deal, why wouldn't you? The only thing I'm not terribly confident about is dealing with the bearings on the ends of the ball screw to eliminate any backlash. I really don't know how best to go about that. I found a thread talking about a system with angular thrust bearings, but the pictures were broken, so it's hard to tell what's going.on.
    So, be cautious of who you buy the ballscrews from. I've seen some bad reviews from some popular EBay suppliers. I am currently buying my ballscrews from BST Automation on Aliexpress, with custom end machining. You just have to contact Fred from BST and ask him for a quote. A little more expensive than some EBay guys, but I have yet to hear a bad review. If you follow my thread on Ballscrews, I will let people know what they are like after they arrive. I expect they will be very nice.

    Because the leadscrews you'd be replacing aren't very long, you can probably get away with 16mm diameter ballscrews for most small mills, which aren't very expensive. Perhaps 20mm diameter max.

    Why wouldn't you? You mentioned a budget of $2000. That could cover a used mill and electronics perhaps if you were very budget conscious. I'm just saying that there may be some cheap options to remove the backlash from what already exists. That requires less time and money, and you'd still have a machine way better than what was first suggested.

    The costs can creep up on you fast when you retrofit everything.

    But if you want ballscrews and have a budget for it, that's better. And some people also replace the gibbs with linear rails. Also more $$ and time.

    Quote Originally Posted by VanIsleDSM View Post
    Making some motor mounts and an adapter to mount the ball nuts seems pretty straight forward. Hopefully I can just get some ball screws custom machined from ebay, heard others talking about that. Maybe copy someone else's spec for the ball screws and their bearing design, because I'm out of my element on that.
    The easy way is to buy a kit for a popular conversion. But, I would avoid kits that don't use bearings, I was reading a thread about a CNC fusion kit that used an oldham coupler, but no support bearings. I wouldn't do that one.

    If you can find a design that uses standard end supports, like BK12 or BK15 and BF12 or BF15, then you can buy those. I bought my end supports on alibaba. "BUN" brand. They are very nice.

    The other option to consider is to continually be checking classifieds kijiji, local EBay, etc, for a mill that has already been converted. Sometimes great deals pop up in the sub $4000 range, when you consider the Canadian dollar, that's not far off your first budget. Just be ready to move some heavy steel and have a place to put it.

    If you're not sure what to do, the easiest is to follow in someone else's foot steps, either via a build log, or a conversion kit. Take your time with it. No rush decisions. That's about all the advice I have.



  6. #18
    Registered
    Join Date
    Mar 2008
    Location
    Canada
    Posts
    20
    Downloads
    0
    Uploads
    0

    Default Re: Build Options?

    Well, step one complete, I bought the mill. I'll be picking it up in a few days, after I somehow manage to make some room in the shop. It was too good of a deal to resist, at $1200 CAD, with a ton of tooling. Bunch of mills, face cutters, saw, spare carbide inserts, clamps, blocks, a vice.. I couldn't resist.

    I've seen many CNC conversions of this mill now, searching around online, so I know it can be done. I may try 3D printing some of the conversion parts from carbon fiber impregnated polycarbonate. It's nearly as stiff as 6061 T6, and should work well for most parts. I might also try printing the toothed pulleys out of nylon as well, instead of buying aluminum ones, to keep costs down. Thanks for the advice NIC, I suppose it's new thread time. Conversion of RF-30 and equivalent type mills, specifically figuring out the bearing situation for the ball screws. I need to get a grasp on how that all works and goes together. Thanks for the tip on BST Automation. I will likely use them.



  7. #19
    Registered
    Join Date
    May 2011
    Location
    Canada
    Posts
    593
    Downloads
    0
    Uploads
    0

    Default Re: Build Options?

    Quote Originally Posted by VanIsleDSM View Post
    Well, step one complete, I bought the mill. I'll be picking it up in a few days, after I somehow manage to make some room in the shop. It was too good of a deal to resist, at $1200 CAD, with a ton of tooling. Bunch of mills, face cutters, saw, spare carbide inserts, clamps, blocks, a vice.. I couldn't resist.

    I've seen many CNC conversions of this mill now, searching around online, so I know it can be done.
    That's always good, not to be the pioneer on your first build. At least now you have some examples to follow.

    Quote Originally Posted by VanIsleDSM View Post
    I may try 3D printing some of the conversion parts from carbon fiber impregnated polycarbonate. It's nearly as stiff as 6061 T6, and should work well for most parts. I might also try printing the toothed pulleys out of nylon as well, instead of buying aluminum ones, to keep costs down.
    That's interesting. I don't have a 3D printer, but if you an print carbon fiber impregnated polycarbonate and nylon, I'd certain like to see how you do that. Not necessarily for CNC parts, but for some other projects I want to do. So please include that in your build log, if you are going to do a build log, which of course you don't have to, but it might help with the build.

    Quote Originally Posted by VanIsleDSM View Post
    Thanks for the advice NIC, I suppose it's new thread time. Conversion of RF-30 and equivalent type mills, specifically figuring out the bearing situation for the ball screws. I need to get a grasp on how that all works and goes together. Thanks for the tip on BST Automation. I will likely use them.
    My pleasure, I really hope it works out well for you. Yes, time for a new thread for you. Build logs typically generate more interest and responses, and I know that there are people here who have done conversions like this who will be more help to you than I can be. Perhaps I should follow my own advice.

    I'll post what my experiences are with the ball screws here when they arrive:

    http://linear-and-rotary-motion/3430...-needed-2.html



Page 2 of 2 FirstFirst 12

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  


About CNCzone.com

    We are the largest and most active discussion forum for manufacturing industry. The site is 100% free to join and use, so join today!

Follow us on


Our Brands

Build Options?

Build Options?

Build Options?