DIY rotary tool from an inrunner

[markz]

These are the specs from other rotaries for sale, at $150+ - Milwakees 12V 32,000rpm. Dremels 12V 1.5A motor 30,000rpm.

Would this 6000kv motor, 5.5T, Max voltage of 7.4 (2S) and Max Current of 50A be good for something like this?
With this ESC

I dont want to spend money on a Dremel, I can't find nothing from search here using terms like "inrunner" "dremel" "DIY" so Im thinking 350W of power is pretty high at 7V and 50Amax with 6000kv the rpm would be 45,000 rpm. I figure make my battery pack so it spins at 32,500rpm, so at 6070kv its 5.35V.

What about a chuck/collet for the shaft (Shaft Size is 3.175mm) for something like this?
http://www.dremel.com/en-us/Accessories/Pages/SubCategories.aspx?catid=2005

 

[Thud]

Isn't there an option for something like this?
http://www.amazon.com/Dremel-100-N-Single-Speed-Rotary/dp/B002BAHF64/ref=sr_1_65?s=hi&ie=UTF8&qid=1452616955&sr=1-65&keywords=tools+dremel

Is cordless a priority?

I love dremels & abuse them terribly....but I could never match the price with a diy set up over what is on the shelf at a local retailer.

 

[Drunkskunk]

That should work, although the chuck listed is suppose to suck. Read the reviews, most of the reviews claim it's a POS. I like the idea of building your own. I built my own dremel-like tool for buffing brass insignia way back in my days in ROTC.

A Dremel is the kind of tool that needs a cord. When you need it, it will have sat unused for a year, and the batteries will be dead. And you'll need it for some 15 second job that makes charging it for 6 hours seem pointless. Or you'll need it to run for 6 hours straight as you grind out the paint from some bizarre shaped metal sculpture garage sale find your girlfriend wants you to repaint for her.
I've had both. I'll never get another rechargeable.

$19.95 for a Fake Dremel at Home Depo. :homedepot.com/p/Fake-Ass-Rotary-Tool-Kit-100-Piece, and that comes with a bunch of tips and bits.
I'm betting you could find cheaper on Amazon, Ebay, or Alibaba.

 

[MrDude_1]

honestly, the cheap chinese "crap" ones are still so good that you probably will not make anything better... unless you're trying to make some kind of portable super powered rotary tool.. :lol:

I have a cordless nicad battery dremel I purchased over 11 years ago.. It still works and I still use it atleast once a month on the dogs paws. Along with project stuff.
Just save an extra month if you have to, and buy a real dremel.. feel free to cheap out on the disposable accessories, but trying to build one instead of buy is penny-foolish and pound foolish. It wont save you money, and you wont have a quality tool that will last.

as far as corded vs cordless, I use my corded one all the time. I use the cordless once a month on the dog, and if I NEEED to do something where its a pain to plug in. no reason to use it otherwise.

 

[amberwolf]

I expect something similar to the DIY weedwhackers and line trimmers would also make a reasonable dremel-clone.

As far as cost goes, though, I'd guess the actual dremel or it's commercial clones would be cheaper, if cost is your only concern.

And I agree about the battery thing, if you don't use it much. I use mine a fair bit, every few weeks at least, though there have been times it's sat for months or even a year or more.


FWIW, the actual true-variable-speed corded Dremel-brand unit I have had since the 1980s is still working, and has only had one part replaced so far--the little coupler-tube used between motor and output so that if the output jams it doesn't destroy the motor (instead, it slips or shears at the coupler). I dont' remember nowadays if those even cost me anything, maybe a dollar-and-change for shipping. It does have a growing issue with the variable-speed control itself (causing issues when I am grinding the dogs' claws, mostly) but I think it just needs to be cleaned. If not, well, I can probably fix it.

 

[markz]

I see some RC motors in the 100A and 125A with plenty of ESC controllers available.
An unloaded dewalt drill on 14.4V uses 7A, under load around 15-20A, my DMM does not read much above that or fuse blows.
Blown 3 sets of fuses now
I'm wondering how many amps a cordless dremel would use under full load?

I figured a RC motor that can take 125A would be a beast of a tool.
That would be a ton of power to do whatever you wanted or needed to do.
Plus its in the ballpark of the RPM of Dremel, but in terms of amperage who knows.
I need to buy a higher current meter, hmmmmm wouldnt the CA read that?
Now I need to find out how to hook up my CA3-DP

I have the Dremel SawMax which I have used and works great. Only bought it to shorten the metal legs on the FoozeBall game to childrens height. Should have just bought a regular Dremel 4200

Yeah I see what you are saying, I'd be into the high powered DIY version for $50 to $75.
Princess Auto sells their house brand Powerfist, they are just like your HarborFreight stores.
Just $35, might as well give it a go, and put the DIY version on the shelf. Its so tempting to build the DIY but I'd never use it.

Is Variable speed good to have?

 

[Punx0r]

There's no point going faster than a regular Dremel as most of the tools can't be run anywhere near full speed anyway. They also can't take much more torque than a standard Dremel (lean on most slightly and they turn to dust). A more powerful version of a Dremel is a die grinder. These take larger, 1/4" shank bits, 3" cutoff wheels etc.

 

[spinningmagnets]

This might have some useful information, its a thread about using RC outrunners for various cordless tool jobs, with links to other similar threads:

"RC Electric Brushcutter"
https://endless-sphere.com/forums/viewtopic.php?f=1&t=22874

 

[markz]

I realize there is much more to a good DIY rotary tool then just a motor, esc and some batteries.
Things like the bearing for the motor shaft. It will cost me in total more the $30 to build one myself, I went out and just bought one.

The Dremel 4200 would have been sweet, but $120+



This is what I just bought from Canadian Tire, about $50cdn, so $36usd. A step up from Princess Auto no-name brand.
Corded, Variable 8,000-32,000rpm speeds with dial. Yeah I am sure I will like it alot.

View attachment 1

First job went well, cutting off some wire clamp for a 100psi tire inflator.
This took more time and was wondering why.

Second job, could have ended differently. I just so happen to snap my first shaft of the 251 piece, rotating at #10 so 35,000 rpm
cutting this,

had to revert to hand cutting, went easy so I used the wrong teeny tiny bit for sure
Shaft went a flying, I am very Lucky! Just hope it didnt land on storage stuff.

---------------------------------------------------------

I want to measure the current running through the machine unloaded and loaded. I will use normal setting on the DMM but if its more then 20A then I will build a divider network and measure amps off one parallel branch. The DeWalt Drill pulls more then 20A, will use the divider on that.

These rotary "dremel" tools use very little amps, just the rotation is needed.
Measurments 0.30A at low speed to 0.55A at highest speed - unloaded.
0.30A stalled 0.60A, and 0.55A stalled at ~1.25A. Which is interesting.
So these brand name rotary tools are just 150W motors perhaps 200W at best.
Unless, there is a converter in these units, converting 120Vac to some kind of DC voltage just like the treadmill motors.
At any more amps, with the same rotation (RPM) the bit on the tool would just break I think.
Just broke another bit doing this test, stalling the motor for very brief time.

 

[amberwolf]

My ancient Dremel is a brushed Universal motor, so it will run on AC or DC.

A more powerful version of a Dremel is a die grinder. These take larger, 1/4" shank bits, 3" cutoff wheels etc.

I have an old Black&Decker version of that.

It's also a universal brushed motor, so I have considered several times making either an SCR (treadmill-type) speed controller for it for AC use, or a FET type controller for DC use, running off both my main ebike batteries in series for about 116VDC hot off the charger. This would give me a speed control, whcih would be really nice, as it spins really fast and is often too fast for the application I have for it. But I dunno that I will ever get around to it.

 

[markz]

This is the shaft that broke off at 35,000rpm, not to sure what its used for. I tried it as a mini cut off wheel. It slowly but surely cut the wired coil clamp for the hose. Did too much pressure on it as you can see the shaft is bent where it broke off. I think its used for those mini buffing cloth discs. I will need to purchase some more of those shafts, and hopefully someone somewhere has better quality cutoff discs and grinders. Those are the 2 I really need.



There are just too many bits and pieces that I would never use.

 

[MrDude_1]

take off the rings from the broken cutoff wheels when you switch them....
but yeah, thats for the cutoff wheels.

You either put a hell of alot of stress on it, or it was a crappy holder. The dremel holder is $4US, but the diamond cutoff disc is a bit more... its also overkill for just about everything.
Try the fiber reinforced discs. They're the ones with the waffle style lines on them.
Dont press hard, just have it spin fast and let the weight of the dremel do the work.

Dremel does make a dimond wheel that looks similar, you can see it on the shaft here:
http://www.dremel.com/en-us/Accessories/Pages/ProductDetail.aspx?pid=545

 

[markz]

Thats the bit I used, for a normal sized bolt, took me a good two minute to cut through.
Arent there ones with better cutting ability, the edge on that diamond bit is smooth.

I will buy some fiber reinforced discs too.

 

[nutnspecial]

My 3c : anything you've been cutting I'd use a corded angle grinder. My first was 20$ harborfreight, and it still works, although I'd highly recommend a better makita or similar with variable speed for a wider variety of capabilities. Still buying cheap cutoff and grinding wheels from HF though. And no, I wouldn't recommend diy'ing one from an inrunner :wink:

Those damn dremels are pretty useless for anything substantial imo, but priceless for the little stuff. I really don't use mine to cut much of anything actually- mostly tight or small scale grinding with rotary burrs.
http://www.amazon.com/ZJchao-pieces-Double-Tungsten-Carbide/dp/B0097QA7OW/ref=sr_1_4?ie=UTF8&qid=1452751227&sr=8-4&keywords=rotary+burr

 

[markz]

Yeah well now I know, at full speed at stall they draw a few amps at most.
Seems like the little bits dont go above 1 1/4" in diameter

My friend uses a battery Dremel for his foot calluses, not sure what bit he uses.
As for my Mastercraft 250pc rotary unit thats about all its good for IMO (So my purchase is not a complete waste, I have spent $30 on useless callus grinders before).

Maybe the Dremels (3000 and 4200 models) are different then my Mastercraft Rotary, but their only good for engraving and little light work.

I can add this unit to my Dremel Saw-Max

It'd still be nice to have my cake and eat it too, with a variable 3,000 to 35,000 RPM massive amp (5A+) draw rotary tool.

A project for another time!

 

[MrDude_1]

My friend uses a battery Dremel for his foot calluses, not sure what bit he uses.

Sanding drum with 120 or 220 grit sleeve. Lol

 

[markz]

Thanks, my calluses are getting thick. It wouldn't be right for a man to hit up a nail salon for removal of calluses even though the ladies may be smoking hot. Perhaps I get the upgraded treatment for extra $ :wink:

My friend uses a battery Dremel for his foot calluses, not sure what bit he uses.

Sanding drum with 120 or 220 grit sleeve. Lol

Check this unit out.......

http://www.hobbyking.com/hobbyking/store/__24853__Turnigy_AquaStar_T20_3T_730KV_1280KV_Water_Cooled_Brushless_Motor.html

Water cooled!!!!!!!

RPM/v: 730kv @ "Y" config. / 1280kv @ "Δ" config.
Max voltage: 41V (11S)
Max Current: 128A @ "Y" 730kv / 229A @ "Δ" 1280kv
Max Watts: 5280w

If I remember correctly, reading up on amps in angle grinders and rotary, is that amps is about cooling and how long the unit can run under load before it heats up. As always my first thought is of power.

Just looking at the amps and watts, no wonder people put these little tiny motors on bicycles. The hard part being the rpm reduction, which produces even more power!!! Tim "The Tool Man" Taylor kinda of power

 

[MrDude_1]

You need to just look at angle grinders.

 

[markz]

OR CNC machining!!!!!

 

[MrDude_1]

OR CNC machining!!!!!

no I was being serious.
for the power level you're talking about in a handheld tool... you just need an angle grinder.

They can be cheap, I have a couple I use all the time that cost me $7 after coupons at harbor freight... and I have a couple that cost me $80. The only diff between the cheap ones and the expensive ones are how loud they are. The right angle gearbox is loud on the cheapies.

most use a large AC motor, but there are newer ones that are battery powered and brushless.

 

[Jonathan in Hiram]

OR CNC machining!!!!!

I'm using a heli brushless on a high speed spindle I made for milling wood on my DIY CNC mini mill.. Works fantastic, I've made hundreds of pounds of sawdust with it.