Post by Honus on Sept 20, 2014 18:59:14 GMT
Everyone knows a rotary tool is super handy to have- you can cut, drill and grind all kinds of materials with them. I find them extremely useful for trimming fiberglass parts and adjusting the fit of small parts when making animatronic systems. I can't imagine not having one of these tools in my shop and I've used (and destroyed) a wide variety of them over the years. So here's a rundown of the types of rotary tools I've used and their strengths and weaknesses.
First up is the small Dremel 7700 cordless tool. I kind of bought this on a whim as I needed something in the garage when I was away from my normal workbench. I have to say it worked a lot better than I expected and I really enjoy using it. It's got enough torque for small sanding/grinding jobs and it's great for drilling small holes in plastics, wood and fiberglass. It's not really powerful enough for using with metals. The small chuck holds cutting bits really well and is easy to use. It has two speeds (high and low) and the battery seems to last a reasonable amount of time. If this is your only rotary tool definitely buy two batteries for it. The biggest advantage of this tool is that it's really small and light and easy to get into tight places. So far I haven't had any trouble with it and it appears to be pretty durable. It's also fairly inexpensive. Dremel does make a more powerful cordless model but it's much more expensive.
Next up is the Dremel 4000 corded rotary tool. This one has a fair bit more power than the 7700, has variable speed and you don't have to worry about charging batteries. It's a fair bit larger than the 7700 but if you're going to do any work with metal the tradeoffs are worth having the cord and larger size. When I was cutting through thick (1/8" to 1/4") fiberglass material on the Iron Man suit the 7700 would bog down but the 4000 worked like a charm. If I could only have one Dremel tool in my garage this would be it.
The other two rotary tools I've used are workbench tools- they are meant to be used in an environment where you are sitting down at a bench and controlling the speed of the tool with a foot pedal. The first one is a Foredom flex shaft. I've used these 8 hours a day, five days a week for over 16 years. The motors are extremely robust as are the flex shafts. These are designed for grinding metal in a production shop and will serve you for many, many years. They are much quieter than a Dremel, the speed control is much more precise and the power difference is night and day- there is no comparison.
The biggest advantage to these tools is the handpieces are interchangeable so you can fit a wide variety of specialty handpieces to the flex shaft. If you can only get one get a #30 handpiece as it's the most durable and it uses a standard Jacobs type drill chuck so you can fit all sizes of cutting tools and drill bits.
This is a #30 handpiece-
Some handpieces use what is called a duplex spring- these make the tool more flexible and easier to use at the bench because the flex drive cable doesn't like to be bent into tight curves. The downside to the duplex springs is that they introduce a fair bit of vibration into the handpiece and they have a tendency to break. Some handpieces are of the "quick change" type- they use a lever or collar to release the cutting tool for rapid tool change. Unlike the #30 handpiece these are a fixed size collet so you can't use different size drill bits with them. They are also not as durable as the #30 because the bearings in the handpiece are much smaller. I've used pretty much every handpiece made for these Foredom flex shafts (Faro, Foredom, Pfingst, Techno X, etc.) so I'm happy to recommend certain models if someone has a particular need. Also these Foredom flex shaft tools are a great buy on the used tool market- they can usually be purchased second hand for a fraction of the cost of a new unit.
This is a Faro quick change handpiece with duplex spring. Most of these type handpieces come with a 3/32" collet-
The last bench rotary tool is the NSK Evolution EMax micromotor and it puts everything else to shame- and of course it's also insanely expensive. It is simply the finest rotary tool I've ever used and they're known for being extremely robust. The big benefit of micromotor rotary tools is the brushless motor is in the handpiece so you're not fighting the tension of a flex shaft drive cable- it's a pretty big deal when you're doing delicate work. The motor turns up to 40,000 rpm and is unbelievably powerful, quiet and silky smooth. There is also a 4:1 gear reduction drive that can be fitted that increases the torque output for jobs that require more cutting power. This is what all rotary tools want to be when they grow up. If you're sitting at a bench grinding metal 8 hours a day it's also worth every penny. I know a couple of model makers who have these and they wouldn't trade them for anything. Foredom and RAM also make micromotors but they aren't in the same league as NSK. They cost a heck of a lot less though...
The NSK base unit-
The NSK micromotor handpiece-
The handpiece with gear reduction fitted-
For most people the Dremel tools will work great, with the nod going to the corded model for the best combination of price/performance.
First up is the small Dremel 7700 cordless tool. I kind of bought this on a whim as I needed something in the garage when I was away from my normal workbench. I have to say it worked a lot better than I expected and I really enjoy using it. It's got enough torque for small sanding/grinding jobs and it's great for drilling small holes in plastics, wood and fiberglass. It's not really powerful enough for using with metals. The small chuck holds cutting bits really well and is easy to use. It has two speeds (high and low) and the battery seems to last a reasonable amount of time. If this is your only rotary tool definitely buy two batteries for it. The biggest advantage of this tool is that it's really small and light and easy to get into tight places. So far I haven't had any trouble with it and it appears to be pretty durable. It's also fairly inexpensive. Dremel does make a more powerful cordless model but it's much more expensive.
Next up is the Dremel 4000 corded rotary tool. This one has a fair bit more power than the 7700, has variable speed and you don't have to worry about charging batteries. It's a fair bit larger than the 7700 but if you're going to do any work with metal the tradeoffs are worth having the cord and larger size. When I was cutting through thick (1/8" to 1/4") fiberglass material on the Iron Man suit the 7700 would bog down but the 4000 worked like a charm. If I could only have one Dremel tool in my garage this would be it.
The other two rotary tools I've used are workbench tools- they are meant to be used in an environment where you are sitting down at a bench and controlling the speed of the tool with a foot pedal. The first one is a Foredom flex shaft. I've used these 8 hours a day, five days a week for over 16 years. The motors are extremely robust as are the flex shafts. These are designed for grinding metal in a production shop and will serve you for many, many years. They are much quieter than a Dremel, the speed control is much more precise and the power difference is night and day- there is no comparison.
The biggest advantage to these tools is the handpieces are interchangeable so you can fit a wide variety of specialty handpieces to the flex shaft. If you can only get one get a #30 handpiece as it's the most durable and it uses a standard Jacobs type drill chuck so you can fit all sizes of cutting tools and drill bits.
This is a #30 handpiece-
Some handpieces use what is called a duplex spring- these make the tool more flexible and easier to use at the bench because the flex drive cable doesn't like to be bent into tight curves. The downside to the duplex springs is that they introduce a fair bit of vibration into the handpiece and they have a tendency to break. Some handpieces are of the "quick change" type- they use a lever or collar to release the cutting tool for rapid tool change. Unlike the #30 handpiece these are a fixed size collet so you can't use different size drill bits with them. They are also not as durable as the #30 because the bearings in the handpiece are much smaller. I've used pretty much every handpiece made for these Foredom flex shafts (Faro, Foredom, Pfingst, Techno X, etc.) so I'm happy to recommend certain models if someone has a particular need. Also these Foredom flex shaft tools are a great buy on the used tool market- they can usually be purchased second hand for a fraction of the cost of a new unit.
This is a Faro quick change handpiece with duplex spring. Most of these type handpieces come with a 3/32" collet-
The last bench rotary tool is the NSK Evolution EMax micromotor and it puts everything else to shame- and of course it's also insanely expensive. It is simply the finest rotary tool I've ever used and they're known for being extremely robust. The big benefit of micromotor rotary tools is the brushless motor is in the handpiece so you're not fighting the tension of a flex shaft drive cable- it's a pretty big deal when you're doing delicate work. The motor turns up to 40,000 rpm and is unbelievably powerful, quiet and silky smooth. There is also a 4:1 gear reduction drive that can be fitted that increases the torque output for jobs that require more cutting power. This is what all rotary tools want to be when they grow up. If you're sitting at a bench grinding metal 8 hours a day it's also worth every penny. I know a couple of model makers who have these and they wouldn't trade them for anything. Foredom and RAM also make micromotors but they aren't in the same league as NSK. They cost a heck of a lot less though...
The NSK base unit-
The NSK micromotor handpiece-
The handpiece with gear reduction fitted-
For most people the Dremel tools will work great, with the nod going to the corded model for the best combination of price/performance.
