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  1. #41
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    re: Fineline Shutdown or Perpetrating a Fraud!!

    Quote Originally Posted by Ntl View Post
    I would like to know the same as far as what type of damage will be caused by the mounting surfaces not being flat or parallel.

    Dan

    Dan,

    I've seen the often, but never an answer. To you have a lawyer like answer, it depends. For instance, out-of-parallel by .002" is going to yield a very different life span than being out by .040". It's going to be pretty machine specific. Honestly, I doubt that anyone has tried to quantify it and reported out on it. We can reasonably conclude that with such tight tolerances, any deviation is bound to have a negative effect. Otherwise, why publish the tolerances? They matter. If things are out so much that there's an obvious bind, life may be pretty short. If all seems smooth, the rails/blocks may outlast you (or maybe not). I'd think with the problem Erik describe, life would be on the shorter side. I doubt you are going to get a clearer answer.

    Gary

  2. #42

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    re: Fineline Shutdown or Perpetrating a Fraud!!

    Quote Originally Posted by GME View Post
    Dan,

    I've seen the often, but never an answer. To you have a lawyer like answer, it depends. For instance, out-of-parallel by .002" is going to yield a very different life span than being out by .040". It's going to be pretty machine specific. Honestly, I doubt that anyone has tried to quantify it and reported out on it. We can reasonably conclude that with such tight tolerances, any deviation is bound to have a negative effect. Otherwise, why publish the tolerances? They matter. If things are out so much that there's an obvious bind, life may be pretty short. If all seems smooth, the rails/blocks may outlast you (or maybe not). I'd think with the problem Erik describe, life would be on the shorter side. I doubt you are going to get a clearer answer.

    Gary
    That's what I'm hoping for, if I can get it close and don't feel any noticeable drag or binding that things will last until I decide to get a new machine. It would just suck do to the labor if the bearings wear out quickly. I seriously doubt the liniar rails can go bad and obviously none of machined parts aside from the pinion gears worry me. I suppose if the bearings went it would give me a excuse to have the steel frame machined since it wouldn't be much more labor once the gantry was removed. If the original steel tube gantry would have had the holes driled tapped properly I would have already had it machined flat in all the crucial areas. Since it wasn't it would be less work to just make a new one from scratch and have everything machined, that still may be a option I'm just not sure I want to keep polishing a turd if you know what I mean.

  3. #43
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    re: Fineline Shutdown or Perpetrating a Fraud!!

    Quote Originally Posted by wmgeorge View Post
    In your haste to "be right" you must of missed the " ground flat" in my reply.

    Please show us the pictures of the machines your making, selling and exporting so we know how to do it right.


    Oh and BTW my machine was not heated and stress relieved and it works fine.

    ADDED: So Gary GME is building a new machine from 80/20 aluminum extrusions, as have been thousands of others done. I am sure they do not meet the .0005 in all planes criteria above. So are all these machines therefore junk? I am looking forward to see the machines your making, please post pictures. Thank you.
    You have to have an understanding of what happens if you Grind CR most times the flatness is worse after it is Ground, it would have to be welded in place, stress relieved and then Ground to be of any use what's so ever

    Yes the extrusions don't get anywhere near where it has to be for linear rail mounting but one company does machine the extrusion for mounting Linear Rails

    Your machine may be working well but every time you use it the Linear Bearing will be wearing more than normal, who knows how long it will last nobody can answer that question
    Mactec54

  4. #44
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    re: Fineline Shutdown or Perpetrating a Fraud!!

    Quote Originally Posted by GME View Post
    I guess I got lucky, although I took an extraordinary amount of care in prep and assembly. I know it's highly unlikely that my Hiwin assemblies meet the published specs, but I can say that everything moves the same, whether individually, loose or tight. I know, because I checked it as part of my assembly setup checklist. Movement was the same in all circumstances. Stiff, but consistently smooth. Perfect? Probably not. Close enough that I cannot detect any difference? Yes. I attribute some of my success to my design and the care I took milling the extrusions for square ends and for length. I would have milled rail mounting surfaces, but my mill isn't even close to large enough for that. Also, there is no practical way to take a bolt together machine to an industrial mill. Too many opportunities going and coming to knock the frame out of alignment. Too much to go wrong. Welded steel is a completely different matter.

    Morale of the story: If you can afford it and are willing to part with the money, buy a welded, stress relieved and milled CNC. I can afford it, but am not willing to part with the money at this point in my retirement. So, I either accept the compromises inherent in my decisions, or I forego a CNC altogether. I chose the former, which is apparently a choice you would never make. Good for you for being able to stick to your principles. I wish we were all so lucky.

    Gary
    If the Bearings have enough clearance in them then you would not notice any difference when mounted on extrusion, Standard Linear Bearing can have up to .004" or .1mm clearance
    Mactec54

  5. #45
    ericks
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    re: Fineline Shutdown or Perpetrating a Fraud!!

    That was why i spent extra money for good quality German made extrusion. Also the company supplying it in Australia cut it very precise...

  6. #46
    Community Moderator ger21's Avatar
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    re: Fineline Shutdown or Perpetrating a Fraud!!

    Yes, it depends on the preload of the bearings. The higher the preload, the more precise the mounting surfaces need to be. The specs I mentioned above were for light preload. As the preload goes up, the tolerances get much tighter.

    All the Hiwin catalog says it that the bearings will wear faster. How much would depend on how much deviation you have.
    Gerry

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  7. #47
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    re: Fineline Shutdown or Perpetrating a Fraud!!

    But if its not binding and cutting square is it still wearing? Everything wears, its part of the cost of using a machine. I doubt a hobby user would wear one out if its not binding, and if its does.... buy a new set of bearings after 20 years or so. Its amazing we have not heard these complaints over on the CNCRP area.

    Gary Campbell does a fine job and I have seen pictures of his work posted, IF I had a commercial shop and needed a machine I would have one of his for sure.
    Retired Master Electrician, HVAC/R Commercial. FLA Saturn 2 4x4 CNC Router

  8. #48
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    Re: Fineline Shutdown or Perpetrating a Fraud!!

    Quote Originally Posted by mactec54 View Post
    If the Bearings have enough clearance in them then you would not notice any difference when mounted on extrusion, Standard Linear Bearing can have up to .004" or .1mm clearance

    FWIW, mine have a medium preload, so the tolerances are tighter than Standard (light preload). I'm not quarreling with anything you've said about linear rail wear when installed on imperfect surface. You've put out good information for any prospective buyer or builder.

    I expect that mine will wear more than they than they would on properly prepared surfaces. How much? I guess time will tell.

    If I had a commercial shop, I would buy a commercial quality machine. I hope mine outlast me, but since I'm just a hobbyist, I can justify buying a new set of rails and blocks, if the need arises. Still way cheaper than buying or building a commercial quality machine.

    Also FWIW, it's iffy whether one would ever get extrusion-based routers to linear rail spec. They are bolted together, after all. Whether milling the extrusions themselves, or adding plates for milling, the completed frame would have to be taken to the machine shop for milling or grinding. The chances of introducing some misalignment during transport - whether coming or going - are a probably high. Then, when the machine gets back to the shop, the surfaces will be only as good one's ability to reestablish perfect alignment. I believe it could be done, but would be a tough job. IMO, the only way to ensure a proper finished product would be using welded steel, stress relief, and then milling/grinding on a suitable large format machine. But then, you are back to a commercial/industrial grade machine. I guess that's why so many hobbyists opt to compromise quality for price. IMO, what important is to recognize and understand the limitations and consequences of going with extrusions.

    Having said all this, I do quarrel with the notion that using linear rails on extrusion-based machines is a total waste, which seems to be your position. Clearly less than optimal, but I'm doubt anyone really knows what to expect over time. We could get a nasty surprise, or a pleasant one. Only time will tell.

    Gary

  9. #49
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    Re: Fineline Shutdown or Perpetrating a Fraud!!

    Quote Originally Posted by wmgeorge View Post
    But if its not binding and cutting square is it still wearing? Everything wears, its part of the cost of using a machine. I doubt a hobby user would wear one out if its not binding, and if its does.... buy a new set of bearings after 20 years or so. Its amazing we have not heard these complaints over on the CNCRP area.

    Bill, I question whether you can correlate cutting square with wear. You can always force the gantry square (to a limited degree with a welded gantry) when homing, but not so much as to cause obvious binding. So the machine may cut square, but still over stress the bearings and cause premature wear. How much wear is an open question.

    I believe it is premature to expect to hear much about the topic on the CNCRP forum. It hasn't been that long since CNCRP switched over to linear rails on its pro machines. Time may show that it it works well, or they don't hold up. IMO, it's too soon to tell.

    Gary

  10. #50
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    Re: Fineline Shutdown or Perpetrating a Fraud!!

    Quote Originally Posted by ericks View Post
    That was why i spent extra money for good quality German made extrusion. Also the company supplying it in Australia cut it very precise...
    You are lucky. I spent hours milling the ends of my extrusions square and to equal length. As far as flatness, mine seem pretty good. Part of it is the material; part my design.

    Gary

  11. #51
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    Re: Fineline Shutdown or Perpetrating a Fraud!!

    Quote Originally Posted by wmgeorge View Post
    But if its not binding and cutting square is it still wearing? Everything wears, its part of the cost of using a machine. I doubt a hobby user would wear one out if its not binding, and if its does.... buy a new set of bearings after 20 years or so. Its amazing we have not heard these complaints over on the CNCRP area.

    Gary Campbell does a fine job and I have seen pictures of his work posted, IF I had a commercial shop and needed a machine I would have one of his for sure.
    There have been posts where hobby users have replace the Linear Bearings, they do not have to be binding for them to wear, 20years good luck with that, hobby users have more than just alignment problems, lubrication corrosion and dust adds to the wear problems as well
    Mactec54

  12. #52
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    Re: Fineline Shutdown or Perpetrating a Fraud!!

    There have been posts where hobby users have replace the Linear Bearings, they do not have to be binding for them to wear, 20years good luck with that, hobby users have more than just alignment problems, lubrication corrosion and dust adds to the wear problems as well


    So what do linear bearing blocks cost? I see USA sourced bearing blocks on a rail for $350 per side on EBay? So if they last 10 years, its a cost of what? I never see posts of anyone replacing any?

    So Gary Campbell has posted pictures of his builds, how are you doing yours that are headed for the commercial market and export? Pictures like Gary posted would tell us.
    Retired Master Electrician, HVAC/R Commercial. FLA Saturn 2 4x4 CNC Router

  13. #53
    Community Moderator ger21's Avatar
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    Re: Fineline Shutdown or Perpetrating a Fraud!!

    Having said all this, I do quarrel with the notion that using linear rails on extrusion-based machines is a total waste, which seems to be your position. Clearly less than optimal, but I'm doubt anyone really knows what to expect over time.
    I'd argue that linear rails bolted to extrusion are still better than any other system on an extrusion based machine.

    The quality of the bearings probably also comes into play, as many machines are using Chinese "off brand" rails and bearings.
    I'd expect genuine, name brand bearings to last longer as their tolerances and quality are probably much better. You get what you pay for.
    Gerry

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  14. #54
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    Re: Fineline Shutdown or Perpetrating a Fraud!!

    Quote Originally Posted by wmgeorge View Post
    There have been posts where hobby users have replace the Linear Bearings, they do not have to be binding for them to wear, 20years good luck with that, hobby users have more than just alignment problems, lubrication corrosion and dust adds to the wear problems as well


    So what do linear bearing blocks cost? I see USA sourced bearing blocks on a rail for $350 per side on EBay? So if they last 10 years, its a cost of what? I never see posts of anyone replacing any?

    So Gary Campbell has posted pictures of his builds, how are you doing yours that are headed for the commercial market and export? Pictures like Gary posted would tell us.


    Bill,

    Here's a thread from back in 2011. I believe it should satisfy at least some of your curiosity. I'm satisfied he's the real deal.

    https://www.cnczone.com/forums/cnc-w...ld-friend.html

    Here's another thread you might find interesting:

    https://www.cnczone.com/forums/cnc-w...dle-build.html

    Gary

  15. #55
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    Re: Fineline Shutdown or Perpetrating a Fraud!!

    Quote Originally Posted by ger21 View Post
    I'd argue that linear rails bolted to extrusion are still better than any other system on an extrusion based machine.

    The quality of the bearings probably also comes into play, as many machines are using Chinese "off brand" rails and bearings.
    I'd expect genuine, name brand bearings to last longer as their tolerances and quality are probably much better. You get what you pay for.

    +1

  16. #56
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    Re: Fineline Shutdown or Perpetrating a Fraud!!

    Quote Originally Posted by GME View Post
    +1
    And except for one or two persons comments to the contrary, this is something I would not loose sleep over Gary, its going to work and be just fine. If its not binding the chances of you and I wearing our machines out is pretty darn slim!! If it does... will replace as needed.
    Retired Master Electrician, HVAC/R Commercial. FLA Saturn 2 4x4 CNC Router

  17. #57
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    Re: Fineline Shutdown or Perpetrating a Fraud!!

    Quote Originally Posted by wmgeorge View Post
    And except for one or two persons comments to the contrary, this is something I would not loose sleep over Gary, its going to work and be just fine. If its not binding the chances of you and I wearing our machines out is pretty darn slim!! If it does... will replace as needed.

    Thanks, Bill. I'm not worried and haven't been. I've been aware of the limitations all along and went to extraordinary lengths to minimize them. I believe mactec54 and Gary Campbell were correct in sounding an alarm. On the other hand, like Gerry, I believe linear rails arguably the best alternative for extrusion-based machines. As you point out, excessive wear can always be addressed with "replace as needed" - assuming it shows up sometime downstream. Unfortunately, high quality rails and bearing blocks (e.g., Hiwin) are a major expense. Peruse this site to see what I mean: https://motionconstrained.com/ This is where I bought mine. Shipping was included. The prices were the best I found.

    I don't know what to say about your Saturn. If you're happy with the way it runs, that's what's important. I am pleased you got one of the good ones - maybe the last good one.

    Gary

  18. #58
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    Re: Fineline Shutdown or Perpetrating a Fraud!!

    Quote Originally Posted by GME View Post

    Thanks, Bill. I'm not worried and haven't been. I've been aware of the limitations all along and went to extraordinary lengths to minimize them. I believe mactec54 and Gary Campbell were correct in sounding an alarm. On the other hand, like Gerry, I believe linear rails arguably the best alternative for extrusion-based machines. As you point out, excessive wear can always be addressed with "replace as needed" - assuming it shows up sometime downstream. Unfortunately, high quality rails and bearing blocks (e.g., Hiwin) are a major expense. Peruse this site to see what I mean: https://motionconstrained.com/ This is where I bought mine. Shipping was included. The prices were the best I found.

    I don't know what to say about your Saturn. If you're happy with the way it runs, that's what's important. I am pleased you got one of the good ones - maybe the last good one.

    Gary
    So are the rails and blocks sold as matched sets or can you buy the bearing blocks sold separate?
    Retired Master Electrician, HVAC/R Commercial. FLA Saturn 2 4x4 CNC Router

  19. #59
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    Re: Fineline Shutdown or Perpetrating a Fraud!!

    You can buy individual bearing blocks, individual rails or rail/bearing block sets. I've assumed that if there is wear sufficient to warrant replacement, you'd replace the set.

    Gary

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    Re: Fineline Shutdown or Perpetrating a Fraud!!

    To test out if the extrusions under the rails will help me get things right, I am going to design some parts I can 3d print out of polycarbonate blend I have on hand. If they work well enough I may just leave them in place, also if they work well I will post up a link to the file for others to print or have printed. I'm trying to decide how extensive I want to make them...for example making them so you can adjust "toe in / toe out" as far as flatness goes. On my last and final attempt to parallel the rails, I had one rail tightened down and it rolled very smoothly with the other rail loose...when I tried the same test with the rails reversed (swapped tight and loose rails) the action was back to being with much more drag...seemed odd to me.

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