Diamond Drag Bits

I’m new to cnc and I need some assistance finding a diamond drag bit that will work with plastic (acrylic), glass and maybe some stone.
Is a rigid bit okay or is a spring loaded bit required?
Can a V-bit of 15 or 20 degrees at about 0.020" depth give acceptable results in plastic?
Hopefully not overly expensive. I understand that you get what you pay for and I don’t want junk but I also don’t want to pay too much.

Thanks for your time.

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Hi Robert,

I had great success with using this bit to engrave acrylic.

90 Degree CNC Diamond Spring Loaded Drag Engraving Tool Bit
EBAY: 90 Degree CNC Diamond Spring Loaded Drag Engraving Tool Bit for sale online | eBay



How much difference does the angle make? Do you need a different one for different materials?

Hi Grim,
I not sure about the different materials. I really only used this tool to engrave acrylic. The manufacture states that this tool can be used to engrave brass, aluminum, fiber board, acrylic, plastic painted surface and more.

I think that they sell this tool with 3 different angles (60, 90, 120). I have the 90 and have engraved hundreds for acrylic plaques with it. No sign of ware on tip and the detail of the 90 was great.


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From what I have seen the angle of the bit ; like vcarve bits; determines the depth of cut.

I’ve just started using a diamond drag on brass. Maybe some of this applies to any material:

Unlike a V-bit, where the depth is determined by the width of the lines between which you’re cutting, the diamond reaches a depth it simply can’t go beyond. That will differ some with the geometry angle. The spring makes up for defects in the flatness of the workpiece. So if your acrylic or your table is slightly further from your router on one side, the bit cuts just as deeply throughout. It also helps with user errors, like asking for a cut that’s too deep for the bit.

For my purpose, (making intricate letters visible) the solution is to run the bit over the surface between the lines that define the letter.

I’ve only bought one bit so far: Carbide 3D’s product: “MC Etcher”. (an obvious pun on the artist, M.C. Escher).