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  1. #1
    Join Date
    Sep 2009
    Location
    Sydney
    Posts
    666

    Default Why do I want a D Bit Grinder

    I’ve had plans to build a grinder to let me grind drills, lathe tools and modify my other machine tools.

    I’m seriously rethinking building something and instead buying one.

    This has lead me down a rabbit hole of universal grinders, aka D Bit grinders or Deckel clones.

    It’s a big investment at around $1000 but I’m wondering if I’d use it or if there are other options.

    Would love to buy second hand but nothing available.

  2. #2
    Join Date
    Jul 2008
    Location
    near Warragul, Victoria
    Posts
    3,718

    Default Kit

    Maybe buy a DIY kit. Just noticed the prices

    Hemingway Kits Quorn Mk3 - Universal Tool & Cutter Grinder

  3. #3
    Join Date
    Sep 2009
    Location
    Sydney
    Posts
    666

    Default

    $1200 before shipping and I have to build it myself. I’d prefer to be under $1000 if I can and the universal ones on the auction site seem to be about there:

    https://www.ebay.com.au/itm/U3-Unive....m46890.l49286

  4. #4
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
    6,444

    Default

    Hi Neevo,

    Why not make it easy on yourself ! At least half of what you have said that you want to do can be done using a DE bench grinder and a few simple jigs.

    I've learnt a lot from building "John Moran's" four facet drill grinder and even more from building the "Brooks TCG" modified of course by me.

    One of the reasons that I made the "Brooks" TCG is that I was struggling to grind single point lathe tools. That issue vanished when I got pointed towards carbide threading inserts. Now my issues are with grinding milling cutters. But that story is still being written.

    Sure you are going to have to make some parts, but there is nothing difficult about that.
    Best Regards:
    Baron J.

  5. #5
    Join Date
    Sep 2009
    Location
    Sydney
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    666

    Default

    The Moran is where my thoughts have been so far, but to do it right I reckon I’m still a few hundred in materials and may not even be able to pull my finger out and complete the build.

    Hence the question on a D Bit grinder.

    I’m also same as you. Moved on to insert cutting for the lathe these days and very rarely think about HSS unless interrupted cuts.

    Also gone to carbide end mills and at $50 a set it’s probably cheaper to buy new ones.

    So it does seem that twist drill sharpening is my key objective and a $1000 drill sharpener is an expensive option.

  6. #6
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
    Posts
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    Default

    Hi Neevo,

    Apart from single pointing threads and one carbide insert boring bar all my other tools are HSS.

    Buying a "D" bit grinder at 1K is an expensive tool for doing drill sharpening, particularly when you could build the "Moran" four facet grinder for very little money. Apart from buying an ER20 chuck which cost less than £15 UK pounds and a few collets, all the materials came from scrap boxes, even the 20 mm precision ground bar was a scrap offcut.

    I think the most expensive bit of material was the length of 32 mm AF brass hex bar, and that came from the scrapyard. Even that could have been replaced by steel.

    So if you think that you are going to have to spend a fortune buying metal you are looking in the wrong places. Excluding the "Parvelux" motor which I was given, you can get a suitable motor fairly easily. Even a 12 volt DC one from a car fan would do the job.

    There were a lot of people on these forums who gave me help and encouragement, because I thought that I hadn't the skill or capability to make the four facet drill grinder ! Grateful thanks to them. But I did and then went on the build the modified "Brooks" TCG. Which I sure that you will have looked at in the projects forum.

    I've seen some of your pictures of your work and I have no doubts that you can successfully make the Moran drill grinder.
    Best Regards:
    Baron J.

  7. #7
    Join Date
    Sep 2009
    Location
    Sydney
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    666

    Default

    I actually already have a few of the parts for the Moran build. A DC treadmill motor and an ER20 straight shank collet holder, even bought some 10mm steel plate and 17mm ground bar.

    Plus I have a lathe and a mill, so making the tool should be possible.

    Let me relook at the machine and how I could build it.

  8. #8
    Join Date
    Jul 2007
    Location
    Perth
    Posts
    332

    Default

    One consideration when using 5C collets to hold drills, is they are only for prime sizes, ie 4 - 5 - 6mm or imperial equivalent etc, so for the linked D bit grinder it would need some other system for the intermediate sizes such as the ER collets on a 5C shank, unsure if this is available, but this would then reduces the horizontal clearance available, so then a saucer wheel is required compared to a cup wheel, diamond / CBN being the best option as oxide wheels require re-truing and make a mess each time they are mounted.
    The Moran grinder referred to by BJ looks to be a good option. If not already seen the video by Stefan Gotteswinter https://www.youtube.com/watch?v=I5b6h1Vddes provides some good info and limitations on the D bit grinder as well as info by Robin Rezetti. Good luck with it, Alan.

  9. #9
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    Sep 2009
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    Sydney
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    Default

    Yeah I’ve watched that Stefan video about 4 times in the last week. Looks so easy

    But I suppose where’s the fun in that? I already have most of the parts so why not get the stock together to do it myself.

    I’ve had this pic saved from Enots Engineering for ages which is the design I’d like to reengineer for myself using ER16 and ER20 straight shank collet holders.

    Doesn’t help me beyond 13mm though but if I have the frame I can at least build a different system for big drills.


  10. #10
    Join Date
    Mar 2011
    Location
    Southern Flinders Ranges
    Posts
    1,536

    Default

    When I look at things like this I always have the words of a mate of mine in the back of my head....
    ’Do you want to make parts, or make tooling?’

    Its kind of sage advice for me, I try not to get bogged down in making tooling that is readily available off the shelf. Fixtures and jigs, for sure, but machinery I generally steer away from unless it’s not available commercially or too expensive to buy commercially (even then I find myself calculating out a labour rate to build so I’m doing apples with apples).

  11. #11
    Join Date
    Aug 2010
    Location
    Toorloo Arm, VIC
    Age
    39
    Posts
    1,270

    Default

    Quote Originally Posted by C-47 View Post
    One consideration when using 5C collets to hold drills, is they are only for prime sizes, ie 4 - 5 - 6mm or imperial equivalent etc, so for the linked D bit grinder it would need some other system for the intermediate sizes such as the ER collets on a 5C shank, unsure if this is available
    5c metric collets are available in 0.5mm steps, and 5c to ER32 adapters are indeed available for any odd sizes, if needed. They're reasonably compact. For some strange reason 5c to ER20 adapters seem to be much longer from a quick search, but eyeballing the diameters, might be possible to make your own 5c - ER20 with a recessed pin tightened collet nut, and contain most if not all of the ER part within the 5c. You'd have to overlay the drawings on top of each other to confirm if that would work...

    Although to be honest I suspect the better option would be to convert the entire collet spindle of the D-bit grinder to ER32 directly - if you start with a 5c model there should be enough meat in the casting to allow it? Not sure whether the Deckel collet varieties have a smaller casting around the collet spindle?

  12. #12
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
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    Default

    Quote Originally Posted by neevo View Post
    I actually already have a few of the parts for the Moran build. A DC treadmill motor and an ER20 straight shank collet holder, even bought some 10mm steel plate and 17mm ground bar.

    Plus I have a lathe and a mill, so making the tool should be possible.

    Let me relook at the machine and how I could build it.
    Hi Neevo,

    You don't want to use such a large powerful motor like a treadmill one ! There is very little load on the wheel, a fan motor from a car will be more than enough !
    Best Regards:
    Baron J.

  13. #13
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    Sep 2009
    Location
    Sydney
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    Default

    Quote Originally Posted by BaronJ View Post
    Hi Neevo,

    You don't want to use such a large powerful motor like a treadmill one ! There is very little load on the wheel, a fan motor from a car will be more than enough !
    The only reason I was going to use it was because I have it on hand with a PWM variable speed module. Would let me turn it way down too.

    If way too much I can always look for something else.

  14. #14
    Join Date
    Sep 2009
    Location
    Sydney
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    Default

    Anyone in Sydney have some advice on best place to get metal for my build?

    I’m after things like steel plate (8mm), 40mm square stock (cast iron or steel)?

    I have a steel merchants not too far from me with a huge pile of offcuts but maybe there are better options.

  15. #15
    Join Date
    Sep 2012
    Location
    York, North Yorkshire UK
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    Default

    HI Neevo, Guys,

    I've just realised that the picture in post 9 is that of the "Worden" ! Somewhere I have the construction details for that grinder. The original motor was a 1/3 HP 2880 rpm induction one. I built a poor copy using a "Flymow" 1500 watt universal motor. I also built a "Triac" speed controller for it. I soon dumped it, far too fast and very difficult to control the motor speed. The speed just fell away as soon as you started to load the motor, so if you upped the speed to compensate, removing the load the motor just over speeded. Not safe at all, too much risk of the wheel flying apart.
    Best Regards:
    Baron J.

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