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    Default Re: New DIY build - design suggestions/ideas welcome

    I admit that the screw holes may not be absolutely perfect in regard to the carriage body, although they should be pretty damn close in all honesty... probably better than any other way of aligning the plate to the carriage that I can come up with in this design. Out of interest, from the first plate to use them, with the carriages installed using those shoulder bolts, rails floating, the rails seem to be as perfectly aligned to each other as I can measure. That means the screws must be doing a pretty good job in lining up plate and carriage otherwise one would expect some convergence/divergance in the rails.

    That said, it's mainly for repeatability as far as I'm concerned - if the mounting plates are removed and replaced, they will always go back on to pretty much the same spot. Should mean less messing around with re-alignment should anything need to be stripped down for moving/maintenance.



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    Default Re: New DIY build - design suggestions/ideas welcome

    Quote Originally Posted by zeeflyboy View Post
    I admit that the screw holes may not be absolutely perfect in regard to the carriage body, although they should be pretty damn close in all honesty... probably better than any other way of aligning the plate to the carriage that I can come up with in this design. Out of interest, from the first plate to use them, with the carriages installed using those shoulder bolts, rails floating, the rails seem to be as perfectly aligned to each other as I can measure. That means the screws must be doing a pretty good job in lining up plate and carriage otherwise one would expect some convergence/divergance in the rails.

    That said, it's mainly for repeatability as far as I'm concerned - if the mounting plates are removed and replaced, they will always go back on to pretty much the same spot. Should mean less messing around with re-alignment should anything need to be stripped down for moving/maintenance.

    They will not be close at all, as far as repeatability there is none, as your shoulder screws are being used incorrectly, you are only relying on the thread which is no way to align anything like this with any accuracy, the back of your plates should of had a slot, 1.5 to 2mm deep the correct size for the top of the bearing blocks to fit into, this is the only correct way of mounting these linear Bearing Blocks that is why they are Ground on the sides at the top, Go to any manufacturers web page for linear rail mounting, and they all will give you the correct mounting of the rails and Linear Bearings

    You can not float the rails to get alignment, the Bearings have clearance so this is not correct also, they could be anywhere, you have to use a dial indicator to align the rails

    Mactec54


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    Default Re: New DIY build - design suggestions/ideas welcome

    Hi, as I'm not a big fan of a moving gantry type router design, only one section raised my hackles a bit and that was the Z axis slide design.

    My opinion is that while it is a definite advantage to have the bearing blocks fixed and the rails moving, it is also a major advantage to have the bearing blocks spread much further apart along the rails to give a bigger slide aspect ratio.

    Most gantry CNC routers suffer form limited clearance under the X axis crossbeam, and those that do increase the height suffer from the cantilevering forces against the Z axis slides......... when the spindle is at it's lowest travel......this should not be so, but is a fact due to bad design.

    You can go wider and above the Y axis saddle slide way to give the longer Z axis bearing spread and a longer Z axis rail.

    Just for example, if the Z axis rails were spaced 100mm apart, the bearing blocks would need to be spaced 200mm apart measured over their ends on the rail.......an aspect ratio of 2:1......rail length to be whatever travel you need, but the longer the travel the longer the bearing block aspect ratio spread needs to be........3:1 or even 4:1.

    It goes without saying that with increased hang down and long Z axis travels the width of the X axis crossbeam and spread of the rails must be increased accordingly to combat twisting forces.

    I would go further to say that you can have quite a large spindle hang down as long as the Z axis slides are supported in a longer bearing block spread on a saddle which can be above the X axis crossbeam, even to having 3 blocks per side.

    I derive this strategy from past experience with planer mills from the 50 's where the Z axis slides were all dovetail types and some very long at that.
    Ian.



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    Default Re: New DIY build - design suggestions/ideas welcome

    Quote Originally Posted by mactec54 View Post
    They will not be close at all, as far as repeatability there is none, as your shoulder screws are being used incorrectly, you are only relying on the thread which is no way to align anything like this with any accuracy, the back of your plates should of had a slot, 1.5 to 2mm deep the correct size for the top of the bearing blocks to fit into, this is the only correct way of mounting these linear Bearing Blocks that is why they are Ground on the sides at the top, Go to any manufacturers web page for linear rail mounting, and they all will give you the correct mounting of the rails and Linear Bearings

    You can not float the rails to get alignment, the Bearings have clearance so this is not correct also, they could be anywhere, you have to use a dial indicator to align the rails
    We'll probably have to agree to disagree on "at all". I think they'll be pretty close for hobby purposes... The issue with machining the back for a lip is that it then relies on my current less than ideal machine to provide a perfectly flat surface rather than the ground eco-cast plate.

    For the side rail mounts it isn't actually super critical - any fore/aft gantry lean induced by a non-level plate could be fixed with shims under the shoulder piece. However it will be easy to check how well the plates are aligned to the rails by just sitting a dial indicator mounted on the bed with the tip sitting on top of the plate. Slide the plate back and forth and if it is level then the readout should stay fairly consistent. If the reading is too far out then I can leave one shoulder screw in place (e.g. the back one) as a general height setting pin and then turn down the other one to give a little more wiggle room to allow adjustment to level using the dial indicator and some strategic tapping.

    More important for the X-axis where a single plate is bridging two rails. I'll see how it is when installed, but similar technique could be used with dial indicator mounted on the gantry beam to check/set the gantry plate to level with the carriages. If after setting the second rail to the first the carriages aren't perfectly smooth then I'll just turn down those shoulders and let the carriages have a bit of adjustment on the bottom.

    If it doesn't work then I'll just have to figure out a new design on a couple of pieces, not the end of the world. At least it is something that is easy to check using an indicator.








    Quote Originally Posted by handlewanker View Post
    Hi, as I'm not a big fan of a moving gantry type router design, only one section raised my hackles a bit and that was the Z axis slide design.

    My opinion is that while it is a definite advantage to have the bearing blocks fixed and the rails moving, it is also a major advantage to have the bearing blocks spread much further apart along the rails to give a bigger slide aspect ratio.

    Most gantry CNC routers suffer form limited clearance under the X axis crossbeam, and those that do increase the height suffer from the cantilevering forces against the Z axis slides......... when the spindle is at it's lowest travel......this should not be so, but is a fact due to bad design.

    You can go wider and above the Y axis saddle slide way to give the longer Z axis bearing spread and a longer Z axis rail.

    Just for example, if the Z axis rails were spaced 100mm apart, the bearing blocks would need to be spaced 200mm apart measured over their ends on the rail.......an aspect ratio of 2:1......rail length to be whatever travel you need, but the longer the travel the longer the bearing block aspect ratio spread needs to be........3:1 or even 4:1.

    It goes without saying that with increased hang down and long Z axis travels the width of the X axis crossbeam and spread of the rails must be increased accordingly to combat twisting forces.

    I would go further to say that you can have quite a large spindle hang down as long as the Z axis slides are supported in a longer bearing block spread on a saddle which can be above the X axis crossbeam, even to having 3 blocks per side.

    I derive this strategy from past experience with planer mills from the 50 's where the Z axis slides were all dovetail types and some very long at that.
    Ian.

    Yeah, moving gantry has it's disadvantages. It has some advantages too... I considered both and moving gantry is just better for my specific needs at the moment. Can't go wider on the Z-axis as I then start to lose X-axis work space since I am machine-size constrained and increased work area is right up there on the reasons for the upgrade in the first place. Similarly If I space the carriages further apart I lose travel which I need. Ultimately everything is a compromise, you just have to decide what is most important for your specific requirements and design to that... I'm hoping that what I have designed will be able to achieve my goal - namely a bigger workspace and higher performance than the current machine in a limited amount of room



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    Default Re: New DIY build - design suggestions/ideas welcome

    Quote Originally Posted by mactec54 View Post
    They will not be close at all, as far as repeatability there is none, as your shoulder screws are being used incorrectly, you are only relying on the thread which is no way to align anything like this with any accuracy, the back of your plates should of had a slot, 1.5 to 2mm deep the correct size for the top of the bearing blocks to fit into, this is the only correct way of mounting these linear Bearing Blocks that is why they are Ground on the sides at the top, Go to any manufacturers web page for linear rail mounting, and they all will give you the correct mounting of the rails and Linear Bearings

    Given that you raised this point I thought I had better quantitatively test it. Given the gantry arms will sit on a saddle plate, these mounting plates do dictate the squareness of the Z to the Y axis, so the closer they are to perfect the easier time I will have making sure the gantry is squared up.

    I figured this was a good method of checking - in theory if the mounting plate is perfectly level then the reading on the indicator should stay at zero as the plate moves from front to back (indicator is metric, 0.000mm resolution)







    Magically, this side was 0.000mm both at front and back, the middle showed -0.006mm which I would guess is due to non-straightness in my current machine's X-axis gantry meaning that there is a slight bow in the top of the plate, but 0.006mm is only slightly larger than the some bacterium is long so I'll forgive it that!

    Sadly, my joy at that stunning level of alignment was short lived - the other side showed one end about 0.072mm out between front and back. Not that bad over a 200mm or so span, but not really at the level of what I'm after.

    So two options - either I just skim down one of the shoulder bolts and surgically tap the mount into alignment, or I make life difficult for myself and add a shoulder for the carriages.

    I decided to try the shoulder method, since i can easily change back and forth between either method then depending on the results of my experiments. The only catch is that since my current machine isn't exactly perfectly accurate, I was largely relying on the flatness of the eco-cast plate to give the required alignment and tolerances... that means machining a pocket to then give the carriages a shoulder to rest on is not ideal as I've then lost the flatness of the plate and am back to relying on my machine's tolerances.

    I decided to try machining a slot, then making a counterpart to go in there which would provide an alignment rail whilst still having the carriage mount to the ground surface of the plate.

    This is the design:




    Doing it retrospectively, I would have machined the whole thing back side first, then flipped over for pocketing the heads of the screws... that would have ensured the absolute best possible alignment between slot and mount plate. Seeing as that option is no longer possible, I used some 6mm H7 dowel pins and pre drilled a pattern into the bed so that the plates are aligned as best as I can manage to the machine.






    Then machined the inserts:






    They fit very snugly, can't feel any play even without the screws in place.







    I then re-ran my indicator test, and while an improvement over the poorer side of 0.072mm, when compared to the perfect side it got significantly worse - it is approximately 0.020mm higher at the back than the front. It is fairly easy to knock it into shape to within around 0.004mm between front and back by loosening the bolts a touch and giving a little tap. I may try just using a little shim material to give a more precise fit. I think aiming for anything more precise than that really is just chasing my own tail since the first test showed the surface isn't flat to more than 0.006mm anyway.

    Hope that was an interesting little diversion!



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    Default Re: New DIY build - design suggestions/ideas welcome

    Quote Originally Posted by zeeflyboy View Post
    It is fairly easy to knock it into shape !
    Which you could of done just as easy without the pretending shoulder bolts

    You have a misconception that the eco-cast plate is machined /Ground flat, it is far from it, the tolerance normally for plate like this is +/- 0.1mm so if you had skimmed the table on your router, then machined the pocket for the linear Bearing,on it, this would of been more accurate than what the plate spec's where

    When using extrusions that are not machined, like for your main frame, then you can't expect to have, anything that is very precise, being able to get it 0.1mm better, is all you should expect for a build like this

    The most important part will be the alignment of the Ballscrews with the Linear rails

    Mactec54


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    Default Re: New DIY build - design suggestions/ideas welcome

    "the most important part will be the alignment of the balls screws with the linear rails"......that has to be the easiest set-up once the linear rails are tied down.

    All you have to do is run the table to one end and put an indicator on the table mounted on a scribing block and zero it on the ball screw top......then run the table to the other end of the table and indicate off the top of the other end of the ball screw.

    You could also use a digital caliper to measure the height of the table top to the top of the ball screw at each end.

    To test the ball screw parallelness to the linear rails is also just a walk in the park......once the linear rails are set up true......... but getting them both level and true to each other will be your first major headache.........just measure from the side face of the rail at one end to the side of the ball screw and do the same at the other end etc etc.
    Ian.



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    Default Re: New DIY build - design suggestions/ideas welcome

    Quote Originally Posted by mactec54 View Post
    Which you could of done just as easy without the pretending shoulder bolts
    I appreciate your inputs but there is no need to come across in such a way... Since you bring it up though the adjustment was with the machined lip, the shoulder screws were in fact repeatable to a point that any adjustment after loosening was undone when tightened back up.

    You have a misconception that the eco-cast plate is machined /Ground flat, it is far from it, the tolerance normally for plate like this is +/- 0.1mm so if you had skimmed the table on your router, then machined the pocket for the linear Bearing,on it, this would of been more accurate than what the plate spec's where
    No misconception. The flatness across smaller pieces is generally actually much higher than the spec given for a sheet, though I admit it is not guaranteed and any given piece can be out by the spec. I do have a bed that I have skimmed flat with my machine, but there is very limited adjustment available to me to get rid of bed twist, bed flex, and spindle alignment - experience of using my machine tells me that in reality tooling plate is generally flatter than what it can achieve. This is just one of the reasons that I am building a new machine.


    When using extrusions that are not machined, like for your main frame, then you can't expect to have, anything that is very precise, being able to get it 0.1mm better, is all you should expect for a build like this
    All the main frame extrusions are in fact milled extrusions from misumi, if you look at the sides the rails are mounted on and where the precision corner brackets are mounted, it is all milled surface.

    The most important part will be the alignment of the Ballscrews with the Linear rails
    There is some adjustment in the end bearing mount where I built it with some space for movement. Once the rails are aligned, it should be a relatively simple to align the screws.


    handlewanker - thanks for the tips, I was thinking of something along those lines.

    Last edited by zeeflyboy; 07-30-2017 at 06:01 AM.


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    Default Re: New DIY build - design suggestions/ideas welcome

    Keep up the great work!
    I think for most of us we are here to learn and share.
    Every time a problem comes up I learn something new.
    I wish I had all my components to measure first lol, but I dont want to purchase the wrong things in the design stage.
    I've spent countless hours designing things around given specs, the whole time I'm wondering if I'm wasting precious time.
    I have gained a lot of respect for designers since starting my project.
    I think the greatest thing I have taught myself in this venture is, not to assume anything.



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    Default Re: New DIY build - design suggestions/ideas welcome

    Nice work Zeeflyboy,

    I'm enjoying this thread.

    I have a similar machine, are you just using a standard misting setup? What cutters are you using?



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    Default Re: New DIY build - design suggestions/ideas welcome

    Quote Originally Posted by mikechandley View Post
    Keep up the great work!
    I think for most of us we are here to learn and share.
    Every time a problem comes up I learn something new.
    I wish I had all my components to measure first lol, but I dont want to purchase the wrong things in the design stage.
    I've spent countless hours designing things around given specs, the whole time I'm wondering if I'm wasting precious time.
    I have gained a lot of respect for designers since starting my project.
    I think the greatest thing I have taught myself in this venture is, not to assume anything.
    Hi....of course you can have something to see the dimensions for the B,O,M......all you have to do is make a full scale mock up in Polystyrene foam sheet, or cardboard if it's a bit big, and then when you have the "machine" in front of you the bad or good parts of the design are apparent............before you even spend a penny on materials.

    OK, so some of us are more gifted with 3D rendition in a CAD program, but some are more visual and relate better to a real object that can be handled and cut about to modify it without breaking the bank etc.

    It doesn't matter what a model looks like if you have to keep cutting it up but it's one way to quickly get to the start line and you can apply real material dimensions to see how it will be joined together.

    I'm lucky in that respect as I live 2 Km from the Polyfoam depot where they can make the basic flat board stuff to your order....very cheaply too.

    Cutting to shape with a simple hot wire cutter and using wood glue is an instant fix solution, and you can build a whole model in less than a day..
    Ian.



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    Default Re: New DIY build - design suggestions/ideas welcome

    Quote Originally Posted by mikechandley View Post
    Keep up the great work!
    I think for most of us we are here to learn and share.
    Every time a problem comes up I learn something new.
    I wish I had all my components to measure first lol, but I dont want to purchase the wrong things in the design stage.
    I've spent countless hours designing things around given specs, the whole time I'm wondering if I'm wasting precious time.
    I have gained a lot of respect for designers since starting my project.
    I think the greatest thing I have taught myself in this venture is, not to assume anything.
    Cheers. Stupid thing is I did have the part to hand, easily could have verified it. Oh well, lesson learned!



    Quote Originally Posted by JermNZ View Post
    Nice work Zeeflyboy,

    I'm enjoying this thread.

    I have a similar machine, are you just using a standard misting setup? What cutters are you using?
    Yeah, you can see some details of the setup in this thread but it's pretty bog standard mister type setup really.

    I use a variety of end mills, but at the moment mostly 6mm 3 flute roughing for adaptive (currently using 8mm depth of cut, 1.5mm radial engagement, 1800mm/min) and then either 6mm single flute or 6mm 3 flute for finishing.


    I'm waiting for some new end mills and some motivation to re-cut the front plate after my motor mount boo boo, but in the mean time I made a start on a low profile machine vice I designed. Haven't been very happy with the low profile vice I already have and want something much stronger and hopefully more accurate.

    This is the overall design, today I made the fixed end:



    Basically it uses a bolt pattern on the bed for alignment dowels and bolting down, but gives access right down to bed level (or below with a cut out I suppose!) which will be useful when trying to machine or drill taller pieces. I have since tweaked the design slightly to allow the travelling end to be bolted down as well if required for extra rigidity.

    Missed taking a photo of the first bits, but basically vertically it is made up of 2 pieces of plate as I don't have any tools long enough to cut the whole thing in one pass and it allows me a bit more flexibility in how it is made.

    After machining the two pieces and bolting them together, I popped them into the machine again and faced them down by 0.2mm on each of the main faces to give a nice flat and square face.






    And after a quick tickle with some 1500 grit wet and dry:






    Once I invest in some anodising equipment the plan will be to give this a nice black anodised finish... assuming the thing works as expected.



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    Default Re: New DIY build - design suggestions/ideas welcome

    Quote Originally Posted by zeeflyboy View Post
    Cheers. Stupid thing is I did have the part to hand, easily could have verified it. Oh well, lesson learned!





    Yeah, you can see some details of the setup in this thread but it's pretty bog standard mister type setup really.

    I use a variety of end mills, but at the moment mostly 6mm 3 flute roughing for adaptive (currently using 8mm depth of cut, 1.5mm radial engagement, 1800mm/min) and then either 6mm single flute or 6mm 3 flute for finishing.


    I'm waiting for some new end mills and some motivation to re-cut the front plate after my motor mount boo boo, but in the mean time I made a start on a low profile machine vice I designed. Haven't been very happy with the low profile vice I already have and want something much stronger and hopefully more accurate.

    This is the overall design, today I made the fixed end:



    Basically it uses a bolt pattern on the bed for alignment dowels and bolting down, but gives access right down to bed level (or below with a cut out I suppose!) which will be useful when trying to machine or drill taller pieces. I have since tweaked the design slightly to allow the travelling end to be bolted down as well if required for extra rigidity.

    Missed taking a photo of the first bits, but basically vertically it is made up of 2 pieces of plate as I don't have any tools long enough to cut the whole thing in one pass and it allows me a bit more flexibility in how it is made.

    After machining the two pieces and bolting them together, I popped them into the machine again and faced them down by 0.2mm on each of the main faces to give a nice flat and square face Once I invest in some anodising equipment the plan will be to give this a nice black anodised finish... assuming the thing works as expected.
    This type of vice works very well, the moving jaw lift can be the problem sometimes, I used to manufacture vices like this and special jaw sets for engraving machines

    Mactec54


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    Default Re: New DIY build - design suggestions/ideas welcome

    Quote Originally Posted by zeeflyboy View Post
    Cheers. Stupid thing is I did have the part to hand, easily could have verified it. Oh well, lesson learned!





    Yeah, you can see some details of the setup in this thread but it's pretty bog standard mister type setup really.

    I use a variety of end mills, but at the moment mostly 6mm 3 flute roughing for adaptive (currently using 8mm depth of cut, 1.5mm radial engagement, 1800mm/min) and then either 6mm single flute or 6mm 3 flute for finishing.


    I'm waiting for some new end mills and some motivation to re-cut the front plate after my motor mount boo boo, but in the mean time I made a start on a low profile machine vice I designed. Haven't been very happy with the low profile vice I already have and want something much stronger and hopefully more accurate.

    This is the overall design, today I made the fixed end:



    Basically it uses a bolt pattern on the bed for alignment dowels and bolting down, but gives access right down to bed level (or below with a cut out I suppose!) which will be useful when trying to machine or drill taller pieces. I have since tweaked the design slightly to allow the travelling end to be bolted down as well if required for extra rigidity.

    Missed taking a photo of the first bits, but basically vertically it is made up of 2 pieces of plate as I don't have any tools long enough to cut the whole thing in one pass and it allows me a bit more flexibility in how it is made.

    After machining the two pieces and bolting them together, I popped them into the machine again and faced them down by 0.2mm on each of the main faces to give a nice flat and square face.






    And after a quick tickle with some 1500 grit wet and dry:






    Once I invest in some anodising equipment the plan will be to give this a nice black anodised finish... assuming the thing works as expected.
    Thanks for the cutting details. Actually now that you mention it I do remember seeing your post on the misting setup / pump.

    I have built a similar machine (https://jeremyyoungdesign.com/category/diy-cnc-router/) and have been cutting aluminium dry with fairly good results. Although I think I can make great improvements by using a misting / micro drop system. I actually purchased a cheap misting head on ebay, but never got around to hooking it up as I also don't have a compressor at the moment.

    I read that standard misting systems can disperse a lot of coolant into the air in the form of mist, which besides not being good for health, also coats the room with oil/coolant! Have you experienced anything like this?

    I've heard that the "MicroDrop" systems are much better, but also fairly costly.

    That vise setup looks interesting, I've also been looking for a decent low profile vise for my machine.

    I see you are using an Acetal/Delrin bed? Much better for precision alignment pins etc. Is it sacrificial? Or do you avoid cutting into it?

    Mine is setup with a 19 mm MDF bed with a matrix of threaded inserts, which is ideal for large sheet stock of wood, acetal etc.. I then have 4 mm MDF sheets which I precut in stacks with holes to match the threaded insert pattern. These are sacrificial, and by precutting the hole pattern I avoid having to cut the sheets to the exact size of each job I do on the machine.

    Cheers,
    J



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    Default Re: New DIY build - design suggestions/ideas welcome

    Can't say I've noticed anything, I do use koolmist #77 specifically for it's safety profile though.

    I believe one important thing to do to ensure droplets rather than mist is to slightly pressurise the coolant (or just raise the coolant for gravity feed I suppose), just relying on venturi appears to give a much finer mist.

    I wouldn't say yours is similar, I'd say yours looks much, much nicer. Lovely machine!

    Mactec - glad to hear you like that style of vice as I haven't used them before. I did a couple of things to try and combat/minimise lift of the travelling jaw, firstly I used 12mm linear rod and extra long bearings (I may substitute for solid bushing as there is no need for bearings really) to attach the jaw to the main body, and secondly I raised the point that the screw pushes on the clamp to above the centre point, which should help push the clamp downwards into the bed rather than up. More recently I also added slots in the travelling jaw to allow it to be clamped down to the bed with M8 bolts once the work piece is clamped. The latter will definitely solve all lift, but slightly awkward in needing extra m8 holes in the bed - will probably only use those when really needed.



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    Default Re: New DIY build - design suggestions/ideas welcome

    Hi, that won't work either......pressing against the moving block above centre.........as soon as the moving jaw is away from the nut block the screw and the jaw will start to pushed up......the jaw will push up anyway and the screw will only follow it.

    For practical purposes that design type is only suitable for very light work like circuit boards etc.

    I would also severely limit the amount the moving jaw moves away from the nut block, not more than the diam of the rod and have the rods held in the nut block by at least 2 X the diam so that the 2 slide rods attached to the moving jaw stop it from rising.

    Having the slots as you said would help a lot.
    Ian.



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    Default Re: New DIY build - design suggestions/ideas welcome

    Quote Originally Posted by zeeflyboy View Post
    Can't say I've noticed anything, I do use koolmist #77 specifically for it's safety profile though.

    I believe one important thing to do to ensure droplets rather than mist is to slightly pressurise the coolant (or just raise the coolant for gravity feed I suppose), just relying on venturi appears to give a much finer mist.

    I wouldn't say yours is similar, I'd say yours looks much, much nicer. Lovely machine!

    Mactec - glad to hear you like that style of vice as I haven't used them before. I did a couple of things to try and combat/minimise lift of the travelling jaw, firstly I used 12mm linear rod and extra long bearings (I may substitute for solid bushing as there is no need for bearings really) to attach the jaw to the main body, and secondly I raised the point that the screw pushes on the clamp to above the centre point, which should help push the clamp downwards into the bed rather than up. More recently I also added slots in the travelling jaw to allow it to be clamped down to the bed with M8 bolts once the work piece is clamped. The latter will definitely solve all lift, but slightly awkward in needing extra m8 holes in the bed - will probably only use those when really needed.
    !2mm is fine that's what I had used and 1/2" , solid bushings yes and lap them to fit the 12mm rods, I used hard chrome bar and sometimes used the case hardened bar, 6mm is plenty to hold down the moving jaw if it needs it, photos of one type I made for Roland Engraving machines, no jaw lift with this design

    Attached Thumbnails Attached Thumbnails New DIY build - design suggestions/ideas welcome-anodized-20parts-2-jpg   New DIY build - design suggestions/ideas welcome-anodized-20parts-1-jpg  
    Mactec54


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    Default Re: New DIY build - design suggestions/ideas welcome

    Quote Originally Posted by handlewanker View Post
    Hi, that won't work either......pressing against the moving block above centre.........as soon as the moving jaw is away from the nut block the screw and the jaw will start to pushed up......the jaw will push up anyway and the screw will only follow it.
    Cheers for the thoughts. I would have thought that depends on where the work piece is being clamped? If clamped near the top (i.e. above the point where force is being applied by the screw) using the jaw steps for example, then sure it will try to lift. But if clamped from the base up surely the tendency to lift will be fairly low... certainly with the crappy vices I've used in the past that seems to have been the case.

    For practical purposes that design type is only suitable for very light work like circuit boards etc.
    To be honest most of my more intensive work seems to be using jig plates and hold down clamps. This is more for drilling/chamfering/general use so probably all more or less falls under what you would deem light work. For those times where I need it to be absolutely solid I'll have those slots for locking it down fully.

    I would also severely limit the amount the moving jaw moves away from the nut block, not more than the diam of the rod and have the rods held in the nut block by at least 2 X the diam so that the 2 slide rods attached to the moving jaw stop it from rising.
    Yeah that's pretty much the plan, the idea is to move it as close to clamped as possible by choosing appropriate bed holes and then just use the screw to tighten the rest of the way.



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    Default Re: New DIY build - design suggestions/ideas welcome

    Quote Originally Posted by mactec54 View Post
    !2mm is fine that's what I had used and 1/2" , solid bushings yes and lap them to fit the 12mm rods, I used hard chrome bar and sometimes used the case hardened bar, 6mm is plenty to hold down the moving jaw if it needs it, photos of one type I made for Roland Engraving machines, no jaw lift with this design

    Very tidy!

    What material do you recommend for the solid bushing? Something fancy like Drylin or something else?



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    Default Re: New DIY build - design suggestions/ideas welcome

    Quote Originally Posted by zeeflyboy View Post
    Cheers for the thoughts. I would have thought that depends on where the work piece is being clamped? If clamped near the top (i.e. above the point where force is being applied by the screw) using the jaw steps for example, then sure it will try to lift. But if clamped from the base up surely the tendency to lift will be fairly low... certainly with the crappy vices I've used in the past that seems to have been the case.



    To be honest most of my more intensive work seems to be using jig plates and hold down clamps. This is more for drilling/chamfering/general use so probably all more or less falls under what you would deem light work. For those times where I need it to be absolutely solid I'll have those slots for locking it down fully.



    Yeah that's pretty much the plan, the idea is to move it as close to clamped as possible by choosing appropriate bed holes and then just use the screw to tighten the rest of the way.
    Hi, I understand what you mean by the low down grip factor applying force that microscopically tilts the jaw over to grip near the top, but the jaw (and the screw) can still lift when force is applied to it.....this is the problem with all vice jaws......except the screwless or toolmaker types that have the jaw forced down at an angle as it's tightened.

    The fact that you will only move the jaw out a small amount to do the final clamping will work OK and largely prevent the lifting.

    The pic of the design by Mactec has given me an idea for a low profile vice project I worked on some years back but did not get joy etc.....now there's light at the end of the tunnel.
    Ian.



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New DIY build - design suggestions/ideas welcome

New DIY build - design suggestions/ideas welcome