Drill-mill fixure for central Dremel mounting

[Murph1090]

You guys break me up some days. You make a threaded threaded collar for the Dremel tool, one of you pisses away hours doing a single point thread on a lathe, the next goes on about the cost of the drill and tap, and I go buy a nut with the right thread and turn the flats off and weld or braze it in place. Might get really lazy, and not even turn off the flats.

Y'all forget the KISS principle in a heartbeat, makes me shake my head.

I've got a friend like that, every damn job requires it to done to show off his artistry, stroke his damn ego, and takes way too long to do. I don't ask him to do anything for me, he was doing a transmission rebuild for me and got pissed off when I walked over to my transmission, put a cupcake with a lit candle on it, and sang "Happy Birthday" to it! Told him in a year, he'd had more then enough time to git it done, time to get his thumb out of his ass and DO IT. Also told him be glad he's a friend; anyone else, I'd have taken a 2# mason's hammer and pounded the thumb in further, so he could feel up his tonsils!

It was done by week's end.

Murph

[Carnel]

I doubt where the "low cost" of electronics is the cause of power electronics failure. Designers mostly use bare or tinned copper traces for high currents. But for a free conductor a current density of 10 A/mm2 is the maximum to tolerate. For a motor current of 10 A and a trace thickness of 35 micrometer you need a trace width of 30 cm! That's impractical. So, as a consequence, in practice you always should cover high current traces with copper wire or strip which can be soldered to the trace. I use 1,5 mm2 up to 10 A, 2,5 mm2 up to 16 amp. So, when you buy electronic boards for high current applications, check which traces draw these high currents and modify your PCB.

[Carnel]

You guys break me up some days. You make a threaded threaded collar for the Dremel tool, one of you pisses away hours doing a single point thread on a lathe, the next goes on about the cost of the drill and tap, and I go buy a nut with the right thread and turn the flats off and weld or braze it in place. Might get really lazy, and not even turn off the flats.

Y'all forget the KISS principle in a heartbeat, makes me shake my head.

I've got a friend like that, every damn job requires it to done to show off his artistry, stroke his damn ego, and takes way too long to do. I don't ask him to do anything for me, he was doing a transmission rebuild for me and got pissed off when I walked over to my transmission, put a cupcake with a lit candle on it, and sang "Happy Birthday" to it! Told him in a year, he'd had more then enough time to git it done, time to get his thumb out of his ass and DO IT. Also told him be glad he's a friend; anyone else, I'd have taken a 2# mason's hammer and pounded the thumb in further, so he could feel up his tonsils!

It was done by week's end.

Murph

Hi Murph1090, I like your reaction very much! It confronts me with my motivation working in my shop.
A sidestep: the thread of the Dremel is not standard (3/4", 12 tpi, 60 deg) so the nut which you want to buy isn't available, I think, and when, you have to buy a full box of 100 or so.
But why spending such a lot of time? In fact this project was growing while working on it. When the opportunity of 3-D printing came up my friend an I were wondering whether one can 3-D print screw threads. And after producing some try outs whith too narrow threads the idea of a tap came up. So, the whole project was playing. And that gives me satisfaction. I do my projects out of hobby and production time is of no importance for me. Being 84 I can afford it. I am glad having enough power to do these stuff.
So, in my opinion, an important difference in motivation is whether production or playing is your motivation.
Thanx for you reply!

[tonyfoale]

Counterbalancing small high speed spindles can add another dimension to the use of such tools. Here is a post that I made a while back. The linked video shows more detail.
DIY high speed sensitive drill press.

[Altair]

Thanks Crusty! We've added your PCB Drill to our Drilling and Drill Presses category,
as well as to your builder page: Crusty's Homemade Tools. Your receipt:

PCB Drill by Crusty

tags: PCB, drill

[wizard69]

Isn't cutting corners on traces being cheap?

I doubt where the "low cost" of electronics is the cause of power electronics failure. Designers mostly use bare or tinned copper traces for high currents. But for a free conductor a current density of 10 A/mm2 is the maximum to tolerate. For a motor current of 10 A and a trace thickness of 35 micrometer you need a trace width of 30 cm! That's impractical. So, as a consequence, in practice you always should cover high current traces with copper wire or strip which can be soldered to the trace. I use 1,5 mm2 up to 10 A, 2,5 mm2 up to 16 amp. So, when you buy electronic boards for high current applications, check which traces draw these high currents and modify your PCB.

[old_toolmaker]

Carnel,

Very nice project and neatly executed also.
Thanks for posting this useful idea!

[mklotz]

Nicely done, Carnel. I've been thinking of mounting my Unimat motor head, capable of high speed, to a 25 mm rod held in the mill collet chuck. This would mean that the Unimat spindle would not be coaxial with the mill spindle but I don't see that as a problem since the main reason for doing it would be to take advantage of the mill's X-Y table and the motor drive for the X axis.

Please be sure to disable the power to the mill when using the Dremel. It's too easy for one's motor memory to take over in a moment of distraction and make you turn on the mill with the Dremel mounted. DAMHIKT. On my mill I have two power switches mounted in series for just this reason. One is the switch I use most of the time. The other is in a hard-to-reach location that my motor memory doesn't remember. Turning the latter off is a great way to prevent me from turning the mill on while some only-power-off operation is under way.

[Carnel]

EDIT: the 3-D printed nut had a short live. Little force did break it. Apparently it could not withstand a pulling force. The inner cohesion was too small. I turned a new alumin(i)um nut and press fitted in the steel strip.