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    I know of people using water cooled spindles who rely on thermal mass, rather than a radiator. Basically, a pond or fountain pump recirculates water to the spindle from a full 5 gallon bucket. I'm told the bucket never gets particularly warm using a 2.2kw spindle for hours on end. Apparently there's enough heat loss in the lines and bucket to dissipate what's picked up at the spindle.

    Luke

    "All I'm trying to find out is the fellow's name on first base" -- Lou Costello


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    Quote Originally Posted by handlewanker View Post
    Hi, I have an ISO20 spindle option with a supply of ISO20 tool holders with ER32 chucks on the end.....$38 each.

    This will give me a 20mm tool capacity, which the ISO20 shank can well handle.......if the R8 can, so can the ISO20 even more so.
    Ian.

    ER32 is very large physically. This was the reason for the design above. it will gain you 2 to 3 inches of clearance over the standard chucks. It also decreases leverage from the tool significantly, reducing chatter and strain on the spindle.

    ISO20 is very small at 22.23mm diametre, and nowhere remotely near the strength and rigidity of R8. BT30 is the R8 equivalent in terms of size. In terms of end mills in a collet chuck, 3/8" is about the max you'll likely use on this spindle, but LENGTH is a far more critical dimension.

    wotzBotz


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    Quote Originally Posted by handlewanker View Post
    That water pump and radiator for the CPU, provided it can shift the heat build up quick enough seems like an ideal solution.
    Ian.
    The nice thing about the CPU kits is they tell you exactly what they can dissipate. They start in around 100W, and go up to 2 or 3 KW. A basic guide for the water cooled spindle would be 90% efficiency, or 10% of its rated power lost as heat. That is about 220w in your case. This is just a guide until you get the real spec of course.

    wotzBotz


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    Quote Originally Posted by Trotline View Post
    I know of people using water cooled spindles who rely on thermal mass, rather than a radiator. Basically, a pond or fountain pump recirculates water to the spindle from a full 5 gallon bucket. I'm told the bucket never gets particularly warm using a 2.2kw spindle for hours on end. Apparently there's enough heat loss in the lines and bucket to dissipate what's picked up at the spindle.

    Luke
    That's how I run my larger machine, just 5-6 litres of undiluted coolant in a tub to the side, using a very small pond pump. The coolant in the tub is in a cooler spot of the workshop that helps, but it barely gets much above ambient no matter whether the machines running 1 or 8 hours continuously.

    cheers, Ian

    It's a state of mind!


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    Quote Originally Posted by ihavenofish View Post
    ER32 is very large physically. This was the reason for the design above. it will gain you 2 to 3 inches of clearance over the standard chucks. It also decreases leverage from the tool significantly, reducing chatter and strain on the spindle.

    ISO20 is very small at 22.23mm diametre, and nowhere remotely near the strength and rigidity of R8. BT30 is the R8 equivalent in terms of size. In terms of end mills in a collet chuck, 3/8" is about the max you'll likely use on this spindle, but LENGTH is a far more critical dimension.
    Hi, I did a comparison profile check with R8, and the ISO20 is only 2mm smaller in diam at the spindle end than R8 which at it's body diam is 25.4mm, but as the R8 collet is hollow I think it's splitting straws to think that ISO20 is weaker.....the R8 may be stronger if it is a solid shank, but to what end?

    Admitted, as designed, the R8 collet holds the cutters deep inside the spindle end, and the ISO20 with ER32 sticks out at the end more, I don't think under CNC conditions I'm going to emulate a manual mill and attempt to hog metal off with a 20mm cutter, it's more for the surface area covered by the bigger more rigid 20mm cutter that the bigger cutter diam scores........I don't think I'd like to have a fly cutter with a 16mm shank and a 100mm sweep.

    At the same time if you want to fit drill chucks for drilling you either have dedicated ISO20 shanks with drill chucks on the end of a taper, or have drill chucks with 20mm parallel shanks in the ER32 chucks........the loss of the extended chuck length is not that much of a burden.

    There's no way known that BT30 shank size can be compared to R8....the end for a start is 30mm diam and solid at that......anything else just attaches to the end of the shank.

    An R8 spindle would only be an option if you were going to go to the TTS tooling method for QTC or ATC.....anything else means you need to remove the collet or tool every time and so lose the Z reference zero point......you would gain height if you had R8, but the gain is debatable.

    I cannot see the point of having a tool shank with R8 when the R8 was designed for collets to have the cutters close up and inside the spindle end and not as a tool shank system, although it can be done, it defeats the object of the design......better then to have ISO30 if the tool with shank needs to be removed from the spindle.

    If the ISO20 spindle with an ER32 chuck proves to be popular as an option to the SVM-0 with just the ER32 spindle end, then Skyfire could have a 75 to 100mm column raiser to cater for this extra need and give anyone who needs the extra height the clearance desired, better than modifying the column casting to give two different column height options........although it would be an interesting proposition, I don't think the higher column would be practical.....where do you draw the line......eventually you come to realise that you really wanted an SVM-1 or 2, and the never ending modification path just works out more expensive and not so reliable anyway.

    On the cooling issue, I have to wonder, if the 5 to 6 litres of water doesn't heat up without a heat exchanger to dissipate the heat to the ambient, then there's not much heat being generated to worry too much about, so a CPU cooler should do the job OK, and I think I'll go down this path for a starter.

    Most of the High Speed Spindle work I want to do will be for carving or engraving, and I think some of those Vectric programs with the exotic designs would go for quite a few hours, so some heat generation would certainly occur.
    Ian.



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    I think you are mixing some things up here.

    the R8 taper is 1.25" at the nose.
    the BT30 taper is also 1.25" at the nose.

    The difference between the two is that bt30 extends a little deeper on the taper, while R8 has a very long 1" section for alignment. The merits of both have been debated to death here on this forum. Fun stuff (not really).

    ISO 20 is MUCH smaller. Approximately half the cross section area of BT30 and R8, and thus half as rigid/strong. But of course, it is still perfectly fine for milling on this machine when used correctly.

    Length is actually rather important here.

    The SVM-0 with this spindle only has about 9" of clearance above the table max. The ER32 chuck will gave a gauge line of near 3". You now have 6" clearance. 1/2" cutter sticks out 2" say... now you have 4". You need 2.5" to release the tool from the spindle and replace it. 1.5" to spare. Works I guess if the work piece is only 1-2" off the table.

    Vise? Not going to work well.

    Drill chuck IN the ER32 chuck? forget it. wont have room to install it let alone work.

    On top of that you have leverage. you have 33mm inside the spindle, 22.225mm diameter. Having the tool tip a good 5 inches from the nose is going to be an incredible leverage ratio and you'll have a lot of chatter on light cuts, and even spindle damage on heavy ones. When you scale that up, it's like having a 12" tool on BT40. which is on the extreme end of safety, and not at all recommended except for maybe plunging/drilling. It's just not worth it to save yourself a few bucks on tooling.





    So, this is why I'm aiming for some tooling that will maximise the machine's envelope. I will also have a riser block under the column if I get one to better accommodate the ATC carousel. This should allow very efficient use of the machine.

    Last edited by ihavenofish; 11-04-2013 at 02:27 PM.
    wotzBotz


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    Quote Originally Posted by handlewanker View Post
    On the cooling issue, I have to wonder, if the 5 to 6 litres of water doesn't heat up without a heat exchanger to dissipate the heat to the ambient, then there's not much heat being generated to worry too much about, so a CPU cooler should do the job OK, and I think I'll go down this path for a starter.

    Most of the High Speed Spindle work I want to do will be for carving or engraving, and I think some of those Vectric programs with the exotic designs would go for quite a few hours, so some heat generation would certainly occur.
    Ian.
    Hi Ian,

    I actually wouldn't even bother going to the trouble of rigging up a fan/radiator system until after you've used the mill and decided for yourself if it's required. A fan in a workshop is just another device to draw dust and debris into places you don't want it IMHO. I'd simply start off with a container of undiluted coolant with a submerged pond pump, if you then found that got too warm, add another container! In fact, you could pick up one of the 20litre plastic brewing drums from Bunnings, drill two holes for the tubes, and the mains plug (you'd need to rewire the plug to get it through the hole), and your done! A large, hassle free, and completely dust free coolant tank where the only possible failure would be the pump itself.

    cheers, the other Ian

    It's a state of mind!


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    What would be nice in a system like that would be the butterfly / spinners inline like we used to see in gas pumps long ago. Just a clear section of pipe where you see a spinner rotating when there is fluid flow. Don't know what those were called. Low tech for sure, but cool non the less.

    Lee


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    Quote Originally Posted by LeeWay View Post
    What would be nice in a system like that would be the butterfly / spinners inline like we used to see in gas pumps long ago. Just a clear section of pipe where you see a spinner rotating when there is fluid flow. Don't know what those were called. Low tech for sure, but cool non the less.

    They make them for the computer cooling kits. They also make glow in the dark hose....

    wotzBotz


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    Oh,,It seems I hve many great inputs to catch up here on the spindle and tooling system these two days...LOL Thanks guys!

    I will need to go to my sheet metal side in next a few days to make sure they won't do anything wrong. I will take some picture there to show here too.

    And we have fixed the website showing problem under chrome or firefox on the weekend.. So should be no problem now

    www.skyfirecnc.com
    Email: info@skyfirecnc.com; Skype: skyfirecnc


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    Quote Originally Posted by ihavenofish View Post
    I think you are mixing some things up here.

    the R8 taper is 1.25" at the nose.
    the BT30 taper is also 1.25" at the nose.

    The difference between the two is that bt30 extends a little deeper on the taper, while R8 has a very long 1" section for alignment. The merits of both have been debated to death here on this forum. Fun stuff (not really).

    ISO 20 is MUCH smaller. Approximately half the cross section area of BT30 and R8, and thus half as rigid/strong. But of course, it is still perfectly fine for milling on this machine when used correctly.

    Length is actually rather important here.

    The SVM-0 with this spindle only has about 9" of clearance above the table max. The ER32 chuck will gave a gauge line of near 3". You now have 6" clearance. 1/2" cutter sticks out 2" say... now you have 4". You need 2.5" to release the tool from the spindle and replace it. 1.5" to spare. Works I guess if the work piece is only 1-2" off the table.

    Vise? Not going to work well.

    Drill chuck IN the ER32 chuck? forget it. wont have room to install it let alone work.

    On top of that you have leverage. you have 33mm inside the spindle, 22.225mm diameter. Having the tool tip a good 5 inches from the nose is going to be an incredible leverage ratio and you'll have a lot of chatter on light cuts, and even spindle damage on heavy ones. When you scale that up, it's like having a 12" tool on BT40. which is on the extreme end of safety, and not at all recommended except for maybe plunging/drilling. It's just not worth it to save yourself a few bucks on tooling.





    So, this is why I'm aiming for some tooling that will maximise the machine's envelope. I will also have a riser block under the column if I get one to better accommodate the ATC carousel. This should allow very efficient use of the machine.
    Hi, R8/ISO30/BT30....they all end at the spindle nose.....anything beyond that is whatever the tool diam body is.

    If 22.5mm is considered weak at 22.5 diam, put a 1" (25.4mm) diam bar of mild steel, as in soft steel, in the vice with a stick out of 1 to 2 inches and see how much force a hammer can exert to bend it......can never happen.

    Now try it with hardened and tempered tool steel that the ISO20 tool holders are made from......if you can bend one of those at the end of the taper I'll eat my hat and anyone else's without any seasoning.......but we are talking about machining under CNC mode not exerting forces that would make a Blacksmith break out in a sweat, and I doubt that the SVM-0's X axis stepper motor could drive the table at full fast traverse with enough force to do damage to the tool holder.

    We are also talking about milling under CNC conditions where the DBMC process is being used...(Death by Many Cuts), or small cuts with shallow DOC and lots of them.....if anyone doubts the strength of the tool holders under those conditions, they haven't used a mill before.

    BTW, if a 16mm cutter with a length of 40mm were to be driven into a vice the cutter would snap off before the tool holder had any damage.

    As far as the spindle to table height is concerned, I'll post a full report of how the set-up works out with the options I have bought.

    LOL.....Skyfire might be asked to supply another column 100mm longer just to please the odd balls.......but I don't think so, even if it did give increased working height without prejudicing the machine layout, it's not something you would do when the SVM-1 is just around the corner with all the bells and whistles.

    I suppose if you got really really desperate for extra height you could fit longer rails and ballscrew to the Z axis and relocate the ballscrew top mounting point to persuade the head to get higher up the column.....hmmmmmm, a distinct possibility if the desperate situation arise......the sky's the limit.

    Joking aside, I think this could be an option to get more column height, but a spacer beneath the column would probably be more effective.

    On the cooling front, I was under the impression the CPU cooler was a fan and radiator unit all in one, and if this is the case the cooling problem is solved.
    Ian.



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    On the cooling front, I was under the impression the CPU cooler was a fan and radiator unit all in one, and if this is the case the cooling problem is solved.
    The best way to cool the spindle is to get a cheap used mini fridge, and install the reservoir in there! And as a bonus it keeps the beer ice cold!



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Show how to build a CNC machine from the very beginning to the end

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