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  1. #21
    Quote Originally Posted by John S View Post
    You need to take everything though, I'm not pissing about wasting diesel to pick 10 bobs worth of gear up.

    What you should NOT do:


    1. Discuss or link to objectionable and/or offensive topics. This is not permitted and includes but is not limited to: things of a violent nature, pornography, sexism, racism and/or other discriminatory subjects, this includes things considered to be as a “joke”. Religious and/or political discussions or anything considered to be of the same nature are not appropriate for these forums and will be removed from public viewing.
    Cheer's John. I understand its not worth the trip just for the Z axis so no problem. I'll wait to hear from Jazz and see if he want these screws. If not you can still have them mate.

  2. #22
    Quote Originally Posted by John S View Post
    You need to take everything though, I'm not pissing about wasting diesel to pick 10 bobs worth of gear up.

    What you should NOT do:


    1. Discuss or link to objectionable and/or offensive topics. This is not permitted and includes but is not limited to: things of a violent nature, pornography, sexism, racism and/or other discriminatory subjects, this includes things considered to be as a “joke”. Religious and/or political discussions or anything considered to be of the same nature are not appropriate for these forums and will be removed from public viewing.
    Come on Lee, been back two minutes and you are already wielding the red pen.
    It was a joke for Christ sake, Jazz even called himself a fat bastard in the post about the Aztec calendar, why don't you edit that ??
    John S -

  3. #23
    Quote Originally Posted by John S View Post
    Come on Lee, been back two minutes and you are already wielding the red pen.
    It was a joke for Christ sake, Jazz even called himself a fat bastard in the post about the Aztec calendar, why don't you edit that ??
    to be fair john he did also edit jazz's earlier comment about you as well where he called u an old bastard... between friends you know it's a joke but from an outsiders point of view you do question sometimes if things are jokes or not

  4. #24
    I don't need Lee to fight my non existent battles, all big boys here. I get on well with Jazz, it's all taking the piss in good fun.

    Just some don't have a sense of humour..................................

    I'd feel happier with this red pen application if he reigned his so called moderators in a bit better.
    John S -

  5. #25
    Quote Originally Posted by Shinobiwan View Post
    I have a gantry that weighs approximately 80kg with spindle. With a decent rate of acceleration let's assume its set to 1000 and 160 steps per in mach with dual RM2010 and 4Nm motors. How much kinetic energy is transferred to the motors when doing a direction change at say 1000rpm or 10m/min? You got to decelerate that 80kg in a very short space of time and I'd hate to think how big this number is going to be or if the motors can even handle that.
    Right, so you have said let:
    acceleration =1000mm/s^2=1m/s^2
    velocity = 10m/min = 10/60= 0.167 m/s (not actually required for the initial calculation)
    mass = 80kg

    It's just newtons 2nd law, so F=ma=80*1=80 Newtons (equivalent to lifting about 8.2kg), so not far off my earlier estimate.

    From the motor's point of view it's not 80N, since we have to consider the ballscrew in between. The ballscrew gives the motors a huge mechanical advantage. The relevant formula, which can be derived from considering the ballscrew as a ramp, is:

    T=F*p/(2*pi*e)
    Where T is the torque, F is the force applied to the nut, p is the ballscrew pitch (so 10mm=0.01m) and e is the efficiency (about 0.9). So chuck the numers in:
    T=80*0.01/(2*pi*0.9)=0.14 Nm

    So changing direction at 10m/min and 1m/s, as you describe, only translates to an extra 0.14Nm torque on the ballscrew, compared to going at a constant speed and 80N force on the ballnut.
    Old router build log here. New router build log here. Lathe build log here.
    Electric motorbike project here.

  6. The Following User Says Thank You to Jonathan For This Useful Post:


  7. #26
    Thanks for that.

    Does that calculation include counteracting the inertia from the screw turning too? I forgot to mention that. I'm interested to see what the total load would be.

  8. #27
    Quote Originally Posted by John S View Post
    Come on Lee, been back two minutes and you are already wielding the red pen.
    It was a joke for Christ sake, Jazz even called himself a fat bastard in the post about the Aztec calendar, why don't you edit that ??
    John I haven’t seen that post of Jazz’s, but if it’s a comment about himself then I don’t think it would/could be perceived in the same way and would lead to anything else.

    Quote Originally Posted by wilfy View Post
    to be fair john he did also edit jazz's earlier comment about you as well where he called u an old bastard... between friends you know it's a joke but from an outsiders point of view you do question sometimes if things are jokes or not
    I did yes, i also then sent this PM to D.C after:

    Quote Originally Posted by Lee Roberts
    I think those comments were ment in jest D.C as they both know each other off the forum, i know how it reads some times though and wish they would stop talking/posting in this way because not everyone knows them both that well and it dose look bad at times.

    We've got it in hand though, thanks.

    .Me
    Quote Originally Posted by John S View Post
    I don't need Lee to fight my non existent battles, all big boys here. I get on well with Jazz, it's all taking the piss in good fun.

    Just some don't have a sense of humour.........
    I know that, some do know that, allot of people dont know that and that's where i come in. A joke is only funny when everyone in the "room" is in on it.

    There's no Red Pen, No one has done anything wrong (as such), im not tapping the badge or picking on anyone. My kids are having a sleep over with their cousins the age range is 3 - 10 so you can imagine what i'm up against, as such im up and down from my laptop like a yoyo, if i'd of had more opportunity i was getting ready to type up a PM to you and Jazz just to let you know why i had removed the comments and there was no "hard feelings" to keep it simple.

    I've kept this short and sweet so i can get it in before it all gets blown out of context and people start chipping in, Merry Christmas John its good to see you active again.

    .Me
    .Me

  9. #28
    Quote Originally Posted by John S View Post
    You need to take everything though, I'm not pissing about wasting diesel to pick 10 bobs worth of gear up.

    What you should NOT do:


    1. Discuss or link to objectionable and/or offensive topics. This is not permitted and includes but is not limited to: things of a violent nature, pornography, sexism, racism and/or other discriminatory subjects, this includes things considered to be as a “joke”. Religious and/or political discussions or anything considered to be of the same nature are not appropriate for these forums and will be removed from public viewing.
    Well Mr Stevenson I saw your Post before the SS jumped in and I must say I've never been so insulted in my life good Sir.

    So on this matter request you meet me Sir in the Central reservation of the M1 for a dual at dawn. (Or when ya eventual fire the zimmer up.!!)

    Bring the Axle grease because the loser gets Rm2005 inserted side ways and Z axis up his Pi$$~£.!! . . . . Now F@~% O%% You Old B%@~% and happy Xmas mate. . X X X
    X X X X X X X X X X X X X X X X X X

    Now I've got a important and just has relevant Calculation for Jonathan.?

    Was in workshop Tuther day and waiting for Job to finish when I felt another Jobbie coming on and while there Nipping the Old vice Cheeks started to wonder just how many Nm of force could be applied thru Cheek power alone.? . . . . Obviously realise this will be a rising rate has desperation sets in so some parameters will be needed..?

    So lets say when at the Turtle point of 15st Fat B@~&$ erds thrust curve when powered by a full Vidaloo madras.?

    Oh and what will be the stall point time curve so know how many liner meters of paper for Clean up.?

  10. #29
    Quote Originally Posted by JAZZCNC View Post
    Well Mr Stevenson I saw your Post before the SS jumped in and I must say I've never been so insulted in my life good Sir.
    You have obviously not been round much then.

    If we are talking about the central reservation on the M1 than lets use the bit just below J27, the Mansfield turn.

    Rather partial to that bit after having removed about 30 metres of it in a wrecker one day doing a slow spiral from slow lane to central reservation.

    So after all the "Pi$$~£.!! . . . . Now F@~% O%% You Old B%@~% and happy Xmas mate. . X X X
    X X X X X X X X X X X X X X X X X X"

    Are you having them ?
    John S -

  11. #30
    Quote Originally Posted by John S View Post
    Are you having them ?
    Yes I would have liked them or at least the chance first but you have them Mate has a Xmas and welcome back present.
    Tried ringing Ant to tell him but not around so if ya speak before I do let him know.

    Oh It's nice having you back around Buddy.!

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