Foredom vs. Dremel

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I have found only a couple of threads dealing with this subject.

The generally accepted wisdom is that Foredom flex shaft motors are superior to Dremel corded tools and this is reflected by the price differential.

There are other flex shafts on the market, notably one had come on sale locally for $70 so I bought it and played with it. I also have a Dremel 400XPR (now discontinued).

I fully realize that the Chinese knock off is not going to be of the same quality as the Foredom but a few things puzzled me about the Foredom vs. Dremel comparison:

1) Is Foredom supposed to be more powerful? The most common "SR" version is 1/6 HP which is appx. 125W. The Dremel has a 2 Amp motor which makes it 240W (the knock off is 150W BTW).

2) Is the revesibility of the Foredom a significant advantage (I can think of only one aplication where it would be)?

3) My main complaint about the Dremel is that it needs both hands to switch it on and off. Has anyone adapted their Dremel for use with a foot pedal? Just a simple on/off one?

4) The knock-off foot pedal is useless where speed regulation is necessary (I tried with the wood carving handpiece and found it pretty difficult to hold the speed down to 1000 rpm where it works best). Is the Foredom foot pedal any better?

At this point the knock off is going back. I have some other concerns about it (electrical grounding or lack of it for one). I plan to get a chuck and a foot pedal for the Dremel. I was just trying to clarify in my mind if I should be saving up for a proper Foredom, i.e. do the extra benefits justify the extra $150 or so.


Daedalus's picture

Commercial model Dremel

You might want to look into one of the commercial models of the Dremel tool.These models have both a foot switch/speed control,a more powerful motor and a heavier flex shaft as well as better quality though out.
To see what one looks like just follow your significant other to the nearest nail salon.

In theory there is no difference between theory and practice.
In practice there is.


Rich Waugh's picture

Well, when it comes to small

Well, when it comes to small motors there's "amps" and then there's "running amps" and even "full load amps." A motor may be rated at 5 amps full load, which is how much current it draws when you stall it out. Another motor may be rated at 5 running amps which is what it draws while running with no load. Both are rated at 5 amps but one is probably twice as powerful as the other. Beware of things rated in full load amps - it's about double the running amps. COmpare apples to apples.

Another factor influencing the actual power of a motor driven tool is momentum. A tiny little motor like in a Dremel hand-held grinder has only about 1/2" radius to the armature, while the motor on a Foredom tool has a 2"radius armature. That makes for BIG difference in momentum when the motor is running and working. That's why big tools that encounter sudden high loads often have big flywheels - to conserve momentum. Old motors typically had bigger armatures than more modern ones, so a 1/3 hp old motor may seem much more powerful than a more modern 1/2 hp motor, yet draw the same current.

What all this means is that a Foredom unit will feel more powerful than a Dremel. It also means that it will be less likely to have the "jitters" when using a coarse burr, because the momentum of the motor is smoothing out the erratic load of the coarse burr to some degree.

Cheap speed controllers don't work. Period. They're just too touchy and don't have smooth dynamic range. If you need that, you need to get a solid-state speed controller. Furthermore, cheap ones are just a resistance element that has a variable tap. When they decrease the available current to the motor they correspondingly decrease the motor's torque. This is bad. A solid state controller, on the other hand, works by clipping the wave form of the electric supply and delivers more nearly full torque throughout the speed range. This is good. Good costs more. That's life.

Rich


crquack's picture

Here is what I

Here is what I measured:

Dremel

No load 35,000 rpm 1.34A
Grinding 35,000 rpm 2.0A
Grinding 18,000 rpm 2.2A

Knock off Foredom

No load 18,000 rpm 0.46A
Grinding 18,000 rpm 0.76A

This makes the knock off far from the advertised 150W.

If one pressed harder the Dremel slowed down a bit, the knock off a lot.

Under the circumstances I decided not to keep the knock off even as a back up. When the Dremel packs up I shall consider splashing out for a Foredom (aparently one is not able to buy just the replacement Dremel tool, one has to buy the whole kit, however useless.)

crquack


bigfootnampa's picture

I agree with what Rich said

I agree with what Rich said and also point out that all Foredoms are NOT equal. They have some more powerful models that the Dremel could not even come close to. I have owned both types (still do... in fact several of the Dremels and some other similar tools besides. No question that for heavy or steady work the Foredom type (mine is actually a Vigor) is better. I do like the easy portability of the Dremel though. My most recently bought model is variable speed and better made than some of my older ones. When I was doing lots of bench work making jewelry I used the flex shaft every day but now that I only have infrequent need for either the Dremels get nearly all the work. My foot pedal on my Vigor flex shaft works quite well and will go from quite a gentle speed right on up though it does take some practice to operate skillfully. My newest Dremel has a dial selector for the variable speed and I really do not miss the foot pedal when working with it.


crquack's picture

The Foredom TX series is

The Foredom TX series is quoted at 1/3 HP which is pretty much identical to the Dremel 400XPR. I suspect that the duty cycle at this input (I assume that is what the quoted figure means, output would be harder to measure) will be quite different for each tool.

Also one has to wonder if the efficiency and thus the output power is going to be greater for the Foredom due to the bigger size of the rotor. Does that convert to a bigger torque? Is the torque related to the momentum Rich was talking about?

crquack


Stephen Fitz-Gerald's picture

Foredom vs dremel

Stephen Fitz-Gerald
I had a Foredom which I liked a lot because of the foot speed control but I lent it to an apprentice who destroyed it...
I was at a yard sale soon after that and bought a Champion Juicer for $10 (without any of the attachments).The owner had lost all the juicing hardware... But I know those motors and they're very strong and very smooth(ball bearings)and what's best is they're relatively slow,which for me is good for polishing stainless which tends to heat up fast from friction.I grabbed it because i thought I'd make a pedestal grinder polisher out of it,(1350 rpm I think).
The same week,I happened to find a flex shaft at a local hardware store for $35 and made a custom fitting to mount it to the juicer motor.The flex shaft has a hand-piece which accepts 1/4"shafts but I have another (Jacobs chuck,I think) that will step down to 3/16ths for my tiny bits.Harbor freight sells a rheostat for about $20 that works fine .It's not a foot control but then I really don't need that...
so for under $100 I have an exceedingly smooth running flex shaft machine.
Just saying...


Daedalus's picture

Field expedient machines

Now that someone else has mentioned it I will expand upon the idea of making what you need rather than buying what they decide to let you have.

If you need HP then go out and find the parts and make your own.
If we can form ,shape and join metal to make art then why not use these skills to make our own tools and machines?
I got tired of shlepping around my heavy 9 inch angle grinder and picked up an old industrial flex shaft at a sale.It was complete with a Jacobs chuck at one end and a mounting bracket at the other.I already have a couple of electric motors that have a Jacobs chuck mounted directly to the shaft so I just chucked the end of my flex shaft in one of them and,instant 1-HP flex shaft that will go places my monster 9" grinder can`t fit and is light enough to use all day long.Far more powerful too.
Summer`s still with us,get out of the shop more,visit the flea markets and auctions.
To quote the Rolling Stones "If you try sometimes,you just might find,you get what you need".
Happy hunting.

In theory there is no difference between theory and practice.
In practice there is.


Rich Waugh's picture

And that, folks, is why so

And that, folks, is why so many of the tools in my shop are homemade. Excellent advice!

Rich


Rich Waugh's picture

Yes, torque is momentum, so

Yes, torque is momentum, so to speak. Torque, expressed as pounds of force per foot (ft/lb) is also called "moment of force" by engineers. The distance from center at which the force is applied is what develops torque - so a bigger radius armature has more torque, all other things being equal (which they never are). Wikipedia has a good discussion of torque which explains it far better than my fumbling can. Check it out.

Rich


crquack's picture

I did and did not find it

I did and did not find it that helpful. However, this was probably the best page for the basic principles:

http://www.mpoweruk.com/machines.htm

OTOH as many have explained in detail to me since, it is far from *that* simple.

Suffice to say that I have accepted the "Mo' better motor = mo'money".

BTW one of the differences between the two companies is that Dremel quote *input* power and Foredom *output* power.

The final thought is that just because it looks like a Foredom does not mean it will perform even close to one.

crquack