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  1. #131
    Attachment 4227
    I use HTD 5M often and they do not have sharp edges, maybe you should smooth it a bit just to keep belt happy?
    Like the concept, did you consider to use RM2010 instead of 2510?
    I wonder what to get RM2510 or RM1010, with smaller one bearing choice is better and they are cheaper as they are smaller.
    Thanks for sharing Jonathan

  2. #132
    The 2788/2720/QCL7C could work i found.

    Reference speed 6700 r/min
    Limiting speed 10000 r/min


    The ball screws and nuts best is to get them from Fred BST Automation, as he has proven himself these years. 3 weeks ago i bought Hiwin from him for 2x 3d printers and he not only gave me the best price around/ i checked just to see the market/ but i had all in 5 days here in Spain.


    As far as the HTD5 rounding, Tom, you are right. I assume most of people will cut them on 4rth axis or indexing head. Anyway below pictures of the absolutely correct profile and size of the 30t puley. I have parametric model that have drawn of HTD5 so if sb say wants a 300T pulley up to specs just drop me aline and will send you a DXF. But here i include the DXF for 30T pulley, the passing hole 27mm and shaft 35mm, needed for the important part in the rotating ball nut. So you can base your drawings correctly.

    Click image for larger version. 

Name:	HTD5 15 30T  27 bore 35 shaft.PNG 
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ID:	20701 Click image for larger version. 

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    Attached Files Attached Files
    Last edited by Boyan Silyavski; 08-02-2017 at 01:49 PM. Reason: forum is buggy
    project 1 , 2, Dust Shoe ...

  3. #133
    Boyan the zip file does not work for me. It might be the spaces in it!!
    ..Clive
    The more you know, The better you know, How little you know

  4. #134
    mekanik's Avatar
    Lives in Barrow in Furness, United Kingdom. Last Activity: 15 Hours Ago Has been a member for 9-10 years. Has a total post count of 786. Received thanks 96 times, giving thanks to others 176 times.
    +1 on that
    invalid attachment.
    Mike

  5. #135
    Re-uploaded the Zip file
    project 1 , 2, Dust Shoe ...

  6. #136
    Works fine now
    Neil...

    Build log...here

  7. #137
    Hello to all. I need some advice. I finally got back to tackling the rotating ballnut. After drawing on turbocad the htd gears on th shaft that fits into the bearing box/block(Shaft with gears machined on it with head piece that attaches to the ballnut) I realized that the 7207 2rs bearings will not fit over the machined gears or the large round headpiece that attaches to the ballnut. If I just find a larger ID like 47 or 50 angular contact bearing with 80 or 90 OD, can I substitute it? Of course I'll make the bearing box accomodate it. Thanks Mutzy

  8. #138
    Quote Originally Posted by mutzy View Post
    Hello to all. I need some advice. I finally got back to tackling the rotating ballnut. After drawing on turbocad the htd gears on th shaft that fits into the bearing box/block(Shaft with gears machined on it with head piece that attaches to the ballnut) I realized that the 7207 2rs bearings will not fit over the machined gears or the large round headpiece that attaches to the ballnut. If I just find a larger ID like 47 or 50 angular contact bearing with 80 or 90 OD, can I substitute it? Of course I'll make the bearing box accomodate it. Thanks Mutzy
    Hows that will not fit? Over no, but there is a sequence of pressing the parts together. That's why the pulley is bored from a separate pulley and then pressed together. if you machine right on shaft, then you will have to machine a smaller pulley so the bearing passes on top of it. But then the ball screwe size pass trough hole, so you will have to check if that's at all possible. I believe it was possible but not sure now. Have to check
    project 1 , 2, Dust Shoe ...

  9. #139
    Click image for larger version. 

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ID:	22974 Can't I just get a larger ID bearing for near the machined on gears to compensate for this?

  10. #140
    Quote Originally Posted by mutzy View Post
    Click image for larger version. 

Name:	gear 1.jpg 
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ID:	22973Click image for larger version. 

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ID:	22974 Can't I just get a larger ID bearing for near the machined on gears to compensate for this?
    I could explain deeper why not, but isn't it easier to bore 4$ pulley than machine a complex part and buy twice as expensive bearing for which you will need bigger aluminum housing which is also more money?????


    I would say generally No. The short answer is: do as i suggest, its best for many reasons or before jumping to buy bigger bearing, just sit down and make a detailed inertia calculation, what snappiness of the machine you need, what will be your maximum speeds and so on. And if that will change the motor you need to bigger!

    Why? lets have as an example my machine 8x4 / in reality 1300x2600mm in metric/. If you invest in long ballscrews you generally make the machine right. Which means the gantry will be heavy around 180 to 300kg. If you gantry on that span is less than 160kg, then go with Rack and Pinion as that means your machine is not made to cut aluminum, so save yourself the trouble.


    Generally if one is there already, one will use servo motors to move the gantry. But next is even more valid if steppers are used.To obtain the right speeds of the machine, the screw will be xx10 , best is the 2510. No need for bigger screw.

    So most probably a gearing has to be used or bigger servo motor. Which means much more money if motor is not Chinese.

    Also i have found that with normal servo motor the most desired ration is like on mine machine 20t:30t. fast enough and geared enough. It gives me a machine that has 307.2 pulse por mm ---- 1/307.2=0.003 mm resolution with maximum speed 20m/min . In reality that speed is 30-40 as my servos can spin to 6k rpm instead of the normal servos 3k rpm

    Anyway, if you feel like, of course there are bigger bearings. But it seems easier for me to preload correctly 2x the same bearings than different sized ones.
    Last edited by Boyan Silyavski; 09-10-2017 at 07:37 AM.
    project 1 , 2, Dust Shoe ...

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