Dremel 1/8 bits

[MikeDe1025]

I've got some 1/8" diameter ball nose bits and a couple of 1/8" diameter down cut bits that are part of a Dremel set. Will these 1/8" shanks hold up to our cnc's?
I know that's a very broad question but I just want to know if these things will snap like an icicle when presented to the wood by our machine even setting our depths very shallow.

Thanks,
Mike

[BillK]

I tightened one in my router collet once and took it out 30 seconds later. It cut terrible, save it for your Dremel.

[Wolffie1]

I made a new bracket for my Dremel and it worked great for engraving and fine lines.
Cheers
Wolffie

[EdThorne]

I have a question. It sounds like these bits work fine when using a Dremel. So, is it not possible to use these same bits will work with a heavier router if the plunge rate, feed rate, and rpm are all properly adjusted for these bits? This would seem logical to me but I am new to CNC. I expect to use 1/8" shaft bits for some fine work and PCB fabrication. I have a Port Cable 892 and bought an aftermarket 1/8" colllet and nut for this router but haven't tried them yet.

[MikeDe1025]

I have a question. It sounds like these bits work fine when using a Dremel. So, is it not possible to use these same bits will work with a heavier router if the plunge rate, feed rate, and rpm are all properly adjusted for these bits? This would seem logical to me but I am new to CNC. I expect to use 1/8" shaft bits for some fine work and PCB fabrication. I have a Port Cable 892 and bought an aftermarket 1/8" colllet and nut for this router but haven't tried them yet.

Ed, I think I can answer this question from you now that the others have basically answered it for me. At first I didn't have a ball nose for the cnc but I did have a tiny 1/8 ball nose as part of my Dremel setup. Well, now I have a regular ball nose and when you compare the two side by side you will know right away why the Dremel doesn't work and the other one does. The Dremel ball nose bit has almost no cutting edges on the bottom of the ball. They're all around the sides which is how you typically use the Dremel. A regular ball nose you'd buy for cnc routing has the cutting edges pretty much wrapped around the ball so that the bottom of it actually cuts. As much cut on the bottom of the ball as on the sides.

Hopefully you other guys will correct me if I'm wrong about that. But from what I see now, I think I'm right.

Mike

[EdThorne]

Thank you Mike. Your answer makes perfect sense. I had read that someone substituted a Dremel for the router and successfully used Dremel bits. Maybe that person wasn't using Dremel's ball nose bits.

Regards,
Ed

[Eagle55]

Also another thing to consider is that you are cutting far more material with CNC that you would ever attempt with the same bit in a dremel tool. The amount of material that the dremel bit is designed to take off per pass is much less than you would expect to do in the Shark. Yes you might be able to adjust the feed rates accordingly but I think the fine tooth spacing of the typical dremel bit would never withstand the slowest feed rates even if slowed down. I think "burn and break" is what I would expect. Also the above answer regarding plunge with a "non-plunge" designed bit is very relevant. There are some router type bits designed for the dremel, but very few and of the ones there are, it is usually going to be better to use bit designed for heavier use than what the dremel tool is capable of. Fine engraving and such like Wolfie mentions would be an exception of coarse.

Roger

[EdThorne]

Also another thing to consider is that you are cutting far more material with CNC that you would ever attempt with the same bit in a dremel tool. The amount of material that the dremel bit is designed to take off per pass is much less than you would expect to do in the Shark. Yes you might be able to adjust the feed rates accordingly but I think the fine tooth spacing of the typical dremel bit would never withstand the slowest feed rates even if slowed down. I think "burn and break" is what I would expect. Also the above answer regarding plunge with a "non-plunge" designed bit is very relevant. There are some router type bits designed for the dremel, but very few and of the ones there are, it is usually going to be better to use bit designed for heavier use than what the dremel tool is capable of. Fine engraving and such like Wolfie mentions would be an exception of coarse.

Roger

Hi Roger,

I appreciate your input. I can see that the tip design is critical to CNC applications as opposed to Dremel applications. I have been buying CNC bits from various sources including Precise Bits. I like that little company as he sells good products with fast delivery and reasonable shipping rates. I like little companies that actually ship on the same day that you order and email you a tracking number. No, I don't work for him.

I am still looking for a larger V-bit like a 90deg 1.25" diameter but haven't found a source for this.

I don't expect to be using very fine bits except for removing copper foil from a printed circuit board or engraving microchannels into plastic. I now know enough to carefully examine the ends of the bits before purchasing same. Thank you!

Regards,
Ed

[Eagle55]

I would check on ebay. There are a lot of bits on there. I don't think I saw an 1 1/4" 90 degree but I did buy a Rockler 3/4" for about $10. There was one guy that had a ton of Rockler bits that had really low prices. He might have one that large. Also you will find a little bit of everything g else at some really good prices. Typically better prices than Presise Bits and pretty good quality over all. Your not likely to find the quality of Presise Bits there. I think there bits are superior to most that I have found hence the slightly higher price although he is still very competitive. I use several 60 degree x 1/4" v bits for wood and corian and really like the whiteside 3 flute bit for engraving pictures and lettering on wood or corian. Probably great for acrylic to although I haven't do e it yet.

Roger

[EdThorne]

Thank you Roger. I will check around eBay to see what they have. I am just starting an inlay project tomorrow. I already have all the toolpath files ready for the morning. I found that the 60deg 1/2" V-bit worked very well for my purposes. I am doing the V-pockets rather than the old-fashioned inlay approach. It all looks good in simulation. Now let's see how this works in reality. I am planning to use a 3/4" end-mill to cut off the excess overlay so that it is even with the surface and then use some sandpaper to finish the job. Hope it works but I won't give up if it doesn't.