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7Feb/10Off

Making of — Dremel holder


Actually this is only the first prototype, so read more, to get known the final version!

As you may know, my first prototype of the heated bed was bended.
I always needed to manually level the bed at the raft stage, because the middle of the bed was lower about 0.5-1 mm.

So the plane was pretty simple:

  • take a right angle Dremel attachment (575)
  • Some cutting disks (420)
  • a Dremel holder

And put everything together:

Hmm, but this article is about the "making of" the dremel holder, so I think I should detail a bit more, how I have done the milling attachment...

I started to design my holder in Blender, but quickly gave up and tried out openscad which turned out an amazing modelling tool.
Not because its particularly fast modelling with it, but because it has two features with no other tool can compete:

  • Born to be version controlled
  • Easy to modify the model afterwards

I took a photo from the part where the new toolhead should matches:

I draw over the photo in Qcad, and extruded in openscad. I also made some modifications like easy bolt access, and nut traps.
Securing the mendel is done with six M4 nuts in a mercedes form:

It has two advantages:

  • The tool can be fixed at an angle
  • it is not dremel specific. Even a pen can be attached to it:

Here is another picture, maybe its is more visible on this one:

So I made the first prototype:

It is big enough, so I think a warming bed is required. I needed to level the bed manually, and thats why I printed it with a raft (to fix the bend of the table). Here is a photo of the raft:

You can see that it has a spiral form of the beginning, I levelled correctly at the fourth path.

The first prototype was not good, it had the following bugs:

      I accidentally mirror-modelled the three holes, so I needed to drill it, to be able to attache to the machine:
      The inner diameter (at the top, and I think overall too) was about 1mm smaller, so I couldn't push the dremel in.
      The nut traps could be about 2mm deeper.
      The nut access holes could be made a bit wider and the walls at an angle
      There is no bolt holder for z limit switch (and also for y), and the bottom of the holder should also push the x limit switch

The whole build took multiple hours, so I made the consequence: I only print the bottom 5mm of the object for the next pototypes.

Second prototype:

The beauty of openscad. I only changed one character to print only the bottom 5mm of the whole build...;-)

Bugs:

      The holder could not push the x limit switch:
      When the z-limit-bolt pushed the y limit switch (top left corner of the machine), it bended too much.
      It was a bit hard to push in. So I made 1mm offset one of the three nut holes

So I made the third prototype

I hardened the bolt holder and also I fixed the holder that it could push the x limit switch. Also I printed the bottom 6 mm, to see how the fixing nuts can be accessed.

Here is it mounted:

Bugs:

  • The bolt of the limit switches had 2mm offset, and could not push the z-limit-switch:

I printed the final version and mounted on the machine:

I really fixed the limit switch problem, here is the proof:

The bolt was too short for the dremel attachment so I bought a 1m long M5 threaded rod, and glued the nut at the end:

And finally the machine begun to mill its bed flat. Here are some action photo:

And also a video:

Milling flat.

Hope you enjoyed this writeup.
I have put online the generated .stl file on thingiverse, as thing:1767.

I will shortly publish the sourcecode too (when github will online again;-()

ps: If you find, that I post too much pictures, just say so.

Comments (3) Trackbacks (1)
  1. Love it, love the photo, love the work you do. Please keep it up.

  2. How are you planning on correcting for the wear of the cutting wheels? From experience they lose about half their diameter pretty quickly. You might want to use an end mill like bit 9901 instead.

  3. > How are you planning on correcting for the wear of the cutting wheels?

    Im planning to do a new post to share the experience, what I gathered.

    > You might want to use an end mill like bit 9901 instead.

    After wearing 15 pieces of cutting disk, I can safely say, that this carbide cutter would be enough for 1 cm2…

    spacexula: Thank you.

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