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  1. #136
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    A photo here might be in order. This arrow mark. Is that on the I.D or the face of the inner ring? A mud map of how the bearing's are arranged and where the spring is would help.

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  3. #137
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    Hi Phil, I attempted to draw you a diagram and it didn't take too long to realise I got nothing of AB when it comes to sketches! So I have supplied a sketch and I have also assembled the thing so you can see what it is supposed to look like. Also, I have since noticed that there are both arrows on the inner and outer race. Question is, if they are alignment marks, how important is it for this application? In assembling the bearings on the spindle, I took the opportunity to align the arrows on the inner race. The arrows on the outer race will prove a little more difficult to align since they become obscured when the end caps are screwed on? OK. Having trouble uploading from work computer, I will do in next post from my phone.... Simon
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  4. #138
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    Cheers.

    Simon
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  5. #139
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    Simon,

    It is interesting to see that Dumore located the outer races within screwed on end caps on your model. The fit of the caps must be pretty good.

    Have you read this? http://www.practicalmachinist.com/vb...ctures-297192/

    Bob.

  6. #140
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    The <-2> That's the bore code. FAG have measured that bore at 9.998mm.

    The triangle symbol, that's the high point of eccentricity. Even if you could measure it, you put that point opposite the run out of the shaft.

    My advise would be to just align those marks up on the shaft

    Phil.

    On Edit I totally get your sketch. The spring is pushing between the bearings. It has to be in a back to back BT arrangement

  7. #141
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    Quote Originally Posted by Anorak Bob View Post
    There you have the Termite, the Buck and the JST.

    I wouldn't wee in any of their ear's if their brain was on fire.

    Null and void link.

  8. #142
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    Thanks Phil, that's exactly what I did when I assembled for the photo, so I'm leaving it as is. The high marks on the outer race are all but impossible to ensure alignment. Sure you can align them before you screw on the end covers but where they end up after screwing tight is anyone's guess. The preload was reasonably easy in the end. I worked out that correct preload was 36 degrees of turn on the preload adjustment screw based on the thread pitch and my spring measurements. Buggered if I was going to measure 36 degrees but I counted the number of "knurls" on the nut and it was 100 so turning by 10 knurls did it. How close is this to the required 6 Kg is of course anyone guess but it got to be a darn sight closer than with my previous idea! Hi Bob, yes those end covers are a very nice sliding fit. Not much play between them and the body. The bearing outer race is a snug sliding fit. As I was explaining about the alignment marks, when you screw on the end caps, sometimes the outer race turns with the cap and sometimes it doesn't. I unscrewed them several times to see if you could predict where the arrow would be but it's not possible. The item mentioned in your link that they could not remove is item No. 46 and it's a dust thrower. Mine is either missing it or it never came with that. I had thought about making one..... My pulleys are too fat! Of course you are quite correct, 1/2" belt is what it takes (silly me). A simple matter of measuring back from the shoulder where the bearing sits and allowing for those spacers would have been a 10 second job to realise there is little over 1/2" left on the shaft for a pulley! Sometimes my brains are in my bum. New pulleys coming up. Cheers Simon
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  9. #143
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    Quote Originally Posted by Machtool View Post
    There you have the Termite, the Buck and the JST.

    I wouldn't wee in any of their ear's if their brain was on fire.

    Null and void link.
    I know nothing of those blokes Phil. After the first nonsensical reply they seemed to be trying to help. I didn't feel right simply posting the thread's accompanying photos here hence the link.

    Bob.

  10. #144
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    Hi all,

    Well with the spindle together and feeling quite nice I redid some spindle runout readings. Pretty much the same as with the old bearings at about 5 - 6 um or maybe 2 tenths. I readjusted the preload once just to be sure I did it right and also because I could feel some notchy (very, very subtle) ball movement which suggested a slightly too high preload. Anyway it feels quite nice now.

    I'm yet to remake the pulleys but I did buy the aluminium for the job. Today I re-wired the trimmer motor so that it would spin the opposite way, did this by internally swapping the brush wiring over. I have since test run it and it does run opposite but does so with some extra sparks. I did anticipate possible issues with running the motor in opposite direction. Not sure if it's purely the brushes wearing a new pattern or if its just simply not meant to run in this direction. Looking at the brushes, they do appear to present to the commutator at 90 degrees so can't see why it would be unhappy. When it is switched off, it spools down in the same maor as previous so it's only the brushes making extra noise.

    I was keen to test out the whole thing eventhough it'd not quite ready. I used the pulleys I made and to attach to the motor I turned down the thread of a 3/8" bolt to 1/4" to fit into the collet of the trimmer. It's not really what I want to do for a proper fit since there is about 1/2" of overhang in oder to align the pulleys and maybe asking a little bit of the 1/4" shaft. I have to admitt it looks and works OK though. I mounted the trimmer to the TP grinder by drilling and tapping into the case of the trimmer and just screwing the existing curved TP grinder bracket to the trimmer. Angular alignment of the trimmer motor was almost assured since the casing of the trimmer is almost a perfect match to the motor mount on the TP grinder. Lining up the pulleys was all that was required, I did this by eye.

    A switch of the on button brought the whole thing to life. The spindle is nice and smooth but I can't say the same for the motor. It's a little bit "shabby" but time will tell with some test grinds. I may have to source a new motor yet but that should be the easy part. At least I have a working spindle now.

    The belt tracks beautifully, better than expected, dead straight. If I do the same in a 1/2" pulley I should be good although I will reduce the crest. I am yet to make an attachment to my compound. What you see in the photos is "an artists impression" it's not even at the correct height. I can't even run it with that wheel on since I am yet to electronically speed control it and it runs at 30K in the 1:1 setup with the trimmer.


    Cheers, Simon

    20150711_162511.jpg20150711_162611.jpg
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  11. #145
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    Nice work Simon. If the thought that the 1/4" spindle is a bit light, you could make up a stepped spindle to screw onto the thread of the motor and then the shaft size to suit the pulley. Would never have thought of using a trimmer motor.
    Kryn

  12. #146
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    Hi Kryn,

    That's what I intended to do. I have been unsuccessful in identifying the thread on the collet nut on the trimmer though. It appears to be a 1mm pitch but the major diameter is an inbetween metric size of (from memory) 13.65mm. I'm thinking of just copying the female nut and using that to make a mating part that will attach to that and then with a shoulder to a 3/8" shaft for the pulley and then a 3/8" thread for a nut. But, I must say this collet attachment with the 1/4" shaft works better than expected.

    My concern at this stage is the motor runs noticably poorer in reverse. I will attach an optical tacho to see if it's indeed doing it's rated 30K but it does not sound like it's spooling up to full rpm either.

    This trimmer is something I have had for 8 years and never used. It seemed an obvious choice since it was looking at me at the time. The rpm and power are "roughly" in ball park although at 520W it has some to spare.

    Cheers,

    Simon
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  13. #147
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    Hi Simon,

    I think you'll find the extra sparking etc is because of brush timing. I doubt there is much you can do about it, unless you can figure a way to rotate the brushes in relation to the stator.
    As I understand it(but likely cant explain it) the the brush timing leads what would be the "normal" angle if the motor was designed to run in both direction. The faster the motor the more lead, its done as thats where current is lowest.

    Hopefully someone will be along shorty to correct my mistakes.


    Stuart

  14. #148
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    Quote Originally Posted by Stustoys View Post
    Hi Simon,

    I think you'll find the extra sparking etc is because of brush timing. I doubt there is much you can do about it, unless you can figure a way to rotate the brushes in relation to the stator.
    As I understand it(but likely cant explain it) the the brush timing leads what would be the "normal" angle if the motor was designed to run in both direction. The faster the motor the more lead, its done as thats where current is lowest.

    Hopefully someone will be along shorty to correct my mistakes.


    Stuart
    Hi Stuart,

    I was wondering whether it was something to do with that. I will forge ahead with my initial idea and see what results I get with the finish. Reading Bob's thread on his TP grinder issues I suspect the proof of the system lies in the finish at the end. If I achieve a reasonable finish I'll be happy with it, if not then I might look for a replacement motor.

    Simon
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

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