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My disc sander

Discussion in 'Hammer & Tongs' started by Natlek, Feb 25, 2016.

  1. Natlek

    Natlek

    Jun 9, 2015
    Ok , this Coffee Grinder will be my disc sander .Motor is 3 Ph. 2 HP and 3000 RPM . What diameter disk to make 10 or 12 inch , and what type of sandpaper to use ? Velcro tip , PSA or what is the best . My experience with this is a ONE big zero :eek:

    Thanks for any help .

    [​IMG]
     
    Last edited: Sep 29, 2016
  2. i4Marc

    i4Marc KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Oct 19, 2011
    I made a pair of these:

    [​IMG]


    What I found is that you really want variable speed with these. I don't have it so I chose 1750 rpm motors instead of 3450 rpm to try to manage control. In my experience 1750 is plenty. The other thing is that since the disc is rotating you can only make good use of the radius of the disc and not the diameter. That means use as large a diameter as you can because you will only be working with half of that. I have seen PSA abrasives in discs as large as 15" diameter. If you plan on using 9X11 sheets then a 9" disc will be optimal. Sheet abrasives are cheaper. You will have to do a little trimming after mounting but that is pretty quickly done. If you go larger than a 9" disc you will likely have to use specific sizes that the PSA discs come in, probably 12" and 15". Some people use feathering adhesive for sticking the paper to the disc because you can peel it off and reapply it later. This allows you to change grits fairly easily. I use spray adhesive with 9X11 sheets. I haven't tried Velcro but I suspect that would not be optimal as it would be too spongy and not offer a hard flat backing surface for the grinding.
     
  3. ONeill

    ONeill KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Nov 15, 2007
    nice dog .
     
  4. Natlek

    Natlek

    Jun 9, 2015
    Thanks for your help i4Marc .Obviously I must bye variable speed control . And the same advice I got about my 2x72 belt grinder ......Thanks again , now it is a lot clearer to me . I'll probably try a 9 inch disc . ...

    Thanks ONeill , keep me company while I work. I love him more than anything else .....
     
  5. williamph

    williamph

    19
    Feb 21, 2016
    I4marc, can you post a pic of your work rest setup? Thanks
     
  6. i4Marc

    i4Marc KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Oct 19, 2011
    williamph,

    I'll take some pics for you. It was just a quick solution to get me going. I still use it but there must be quicker adjusting and more versatile designs out there.


    Pics:


    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
     
    Last edited: May 1, 2016
  7. williamph

    williamph

    19
    Feb 21, 2016
    Thanks Marc that looks pretty easy to setup I just finished my disc and need a work rest now but don't particularly want to spend 400 on one because that's about all I have into the disc/motor/vfd lol
     
  8. Natlek

    Natlek

    Jun 9, 2015
    I finally found time to make disc.This one is 10 inch dia. Tomorrow I will glue 5mm thick 10 inch dia G10 material for easy take of glue for sandpaper . I wonder is this MDF /almost inch and half thick /safe to run on 3000 RPM ? I got switch for left / right turn and remains me to make rest setup , but that is easy task ...........
    And I make another one , much smaller , 7 inch dia. on 1400 RPM . I tried this one / first time in my life/ and I like it. Already I can see what I can do on it .......Is there a problem for bearings if I use it horizontally? I think I have better control of what I'm doing ?

    [​IMG]
    [​IMG]
     
    Last edited: Sep 24, 2016
  9. Natlek

    Natlek

    Jun 9, 2015
    OK, I'm done with this big boy . My calculation shows that disk turns around 40m/s . I glue 40 grit sandpaper and this things eat steel like wood :)

    [​IMG]
    [​IMG]

    And I tried to grind some blade . I am satisfied .... kneeling , and out of hand for first time , here is the result ............this three blank from down ... I stopped at time ,to do not ruin them. I will finish them in my file jig . Left me a little practice to use this before I try for real .
    And I think that next I can grind some distal taper blade on this disk.
    I intend to make another one with 10 inch disk , but on 1400 RPM , mostly for work on wood .This one is to fast .

    [​IMG]

    This is how I'll do work rest for this disc sander , simply and efficiently and moving in all directions and any angle . I hope from picture is clear and you recognize auto engine parts that I will use . Will be to hard to me to explain with words .
    Thanks for help !

    [​IMG]
    [​IMG]
     
    Last edited: Sep 29, 2016
  10. Natlek

    Natlek

    Jun 9, 2015
    I like disk sander that much that I will make another two .One slow for wood and another one fast , 43m/s .For this fast one /27cm. Dia. /I m thinking to make disk like this on picture to grind blade ? What do you think guys ?

    [​IMG]
     
  11. Natlek

    Natlek

    Jun 9, 2015
    That's it ! I'm done with this work rest ,need to decide Al or steel plate above this micarta plate ? Move in any direction you want and always on same distance from disc .

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    I need one second to move it aside from disc

    [​IMG]
     
    Last edited: Dec 8, 2016
  12. Mecha

    Mecha Madscienceforge.com Knifemaker / Craftsman / Service Provider

    Dec 27, 2013
    Nice Natlek, clever use of the cam bearings(?) for adjustability.
     
  13. Natlek

    Natlek

    Jun 9, 2015
    Thanks Mecha .Yes , they are cam bearings from BMW V8 engine :)
     

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