[Fozzie55]

Hi

I have a 1 metre square CNC table, very light duty with a Dremel rotary drill.
I am drilling (peck is it?) over 10,000 little 1mm dia, 5mm deep. holes all over a piece of foamex or MDF. It runs at about 4 hours to complete in Mach 3.

Is it okay to run in one go please? The dremel is running on the slowest speed setting, it won't overheat will it?

Cheers, newbie

[Fozzie55]

Sorry, not cool to reply to own thread and not given you guys much time to help but I need to drill this today. I don't want to kill my dremel. I know commercial machines must route and drill for hours on end but what about a £50 hobby dremel please? Not taxing on it really, 1mm peck drilling into foam PVC. Thanks

[Al_The_Man]

Probably on slow speed it may not be a problem, but as a general rule, series motors are intermittent rated.
Even your average series router motor is not rated continuous, although many run them for hours on end.
Just monitor the temperature.
Al.

[aka9950202]

I have burnt out 2 Dremel series 300's on very long runs We are talking 6 to 8 hour runs. I switched to an Ozito and it has not missed a beat. The brushes have worn out once and have been replaced. So far over 20 hours (5 hours at time) on the Ozito since the new brushes.

The runs have been wood carving with 3mm relieve. The only real test is time and when it starts acting buy another one. They are not build for this type of work.

Cheers,

Andrew in Melbourne

[Ron Dunn]

Fozzie, I'd also be worried about how often you are going to break a drill in that time.

10,000 holes is a LOT. Dremels have a lot of run-out, even if the Dremel keeps going it might be too much for the drill.

(This isn't just a free kick at Dremel. I'm wearing out my second Dremel 300 on a Fireball V90, but its job is to cut tool mounts for its replacements)

[louieatienza]

I'd be more worried about the plastic bearing housing melting and causing problems. I have a RotoZip which is more heavy duty than a Dremel, and I melted the bearing housing after only 1 hour of work (though the newer ones have full metal bearing housings...)

[aka9950202]

I'd be more worried about the plastic bearing housing melting and causing problems. I have a RotoZip which is more heavy duty than a Dremel, and I melted the bearing housing after only 1 hour of work (though the newer ones have full metal bearing housings...)

This is something I have looked into on other projects. The casing of the Dremel or any of that type of tools is flexible. If you don't mount it correctly the casing distorts and the bearing don't run true. This causes the heating of the bearings and over heating of the spindle. That is how I lost the first tool. How I lost the second one is still a mystery to me. I thought I had everything right but....

If you can use the collar of the Dremel in the mount you will get far superior results. It has a M20 thread.

Cheers,

Andrew

[Fozzie55]

Thank you for your advice. Well it doesn't sound promising does it

The stuff it is doing will hopefully be going in the machine created art section.

I did one piece a month ago, the tool I had was some cheapie 18v hand tool. That did 12,500 holes and was fine so I thought I would invest in a Dremel, it has got to be better I thought.

Anyway, I will have to run it through. When I burn this Dremel out what do you guys recommend as a tool to do this in future? Mine is a lightweight machine so a tool of similar size and weight of a Dremel please.

[Ron Dunn]

I'm replacing my Dremel with a Proxxon LB/E. Sorry, but I'm still making the mounts and I can't give you any performance/reliability comparison yet. I can tell you there is definitely less runout and vibration, and a more solid bearing and collet arrangement, but I've yet to cut something in anger.

[Fozzie55]

Thanks for the info on Proxxon. They look good machines, and the long neck one looks easier to mount.

[Fozzie55]

Well I can answer my own question now. It has been running for 10 hours non stop and I have drilled 15,000 holes with one drill. No heat to speak off when I turned it off, casing was still blowing out cool air.

cheers aka9950202, I had it mounted through the collar. I used the circle cutter accessory with the arm bent at 90 degress and bolted to Z axis.

I will look into a Proxxon if I burn this out next time.

[Fozzie55]

Still conscious from the feedback that the Dremel may not be up to this long term. If I got something similar, as long as it has metal bearings and gears would that be okay?
Is Proxxon the way to go?
Thanks for your help.

[aka9950202]

The Proxxon looks to be the best bet. I am saving up to get one and would follow your progress with great interest.......... (Sounds a little Star Warsish!)

Cheers,

Andrew

[Ron Dunn]

Give me another couple of weeks and I'll be able to report on the durability of the Proxxon.

So far I've only got about two hours of cutting. I do 2.5d stuff, so it will take me a long time to build up to the hours you'd experience if doing 3d work.

I'm delighted with the minimal runout, and pleased with the lower noise compared to the Dremel it replaced. Let's hope it lasts!

[Fozzie55]

Cheers guys. Yes the Proxxon IB/E looks like my next buy. I have ordered a 20mm collar mounting bracket already, just in case

[rowbare]

The Proxxon would probably be your best bet.

Like any high speed device, the bearings will eventually wear. This thread mentions a few places that sell ceramic hybrid replacement bearings for it: http://www.cnczone.com/forums/bencht...placement.html.

bob