Thread: Can This Sort of Speed Control Be Done?

The more you slow the router down this way the more power you get, unlike electronic speed controls.

It is impossible to get more power out than you put in as this would break the law of conservation of energy.
What can be gained is greater torque (turning force) which can be used to cut more/deeper per rev, but because a certain number of cutters/teeth/blades chipping/cutting/shaving out wood per second is required to physically cut and remove the wood it would take longer to make the cut.

Some recovery could be obtained by reshaping the profile of cutters/teeth/blades to take bigger bites but then you run into problems like chip/dust clearance so you need a physically larger size cutter. Then if you try and take too large a bite you can run into troubles with tear out. It's just easier to run things faster.

The more you slow the router down this way the more power you get, unlike electronic speed controls.

Electronic speed control can get you close to full power across a wider range of RPM, its just a matter of using the right sort of electronics. Even a basic 3Phase motor driven by a VFD can generate full power from 50 to ~120 Hz. Specially designed water cooled spindles as used on CNC machines running on vector controlled VFD can get close to full power across an even wider frequency range. I see that some members are already getting into this space.

Originally Posted by BobL

[/COLOR]It is impossible to get more power out than you put in as this would break the law of conservation of energy.
What can be gained is greater torque (turning force) which can be used to cut more/deeper per rev, but because a certain number of cutters/teeth/blades chipping/cutting/shaving out wood per second is required to physically cut and remove the wood it would take longer to make the cut.

Maybe I didn't explain it right, but you are right you would have a mechanical advantage or more torque of a ratio of 2 in to 3 out which would effectively give the router 1/3 more torque (gears or pulleys its the same) at the same time lowering the speed to where you could use larger bits like the panel cutters at optimum revs:

Change Force; If the 'Driver' gear is smaller than the 'Driven' gear the speed of rotation is decreased, however, the force applied is increased. The increase in torque occurs much in the same way a lever is given a mechanical advantage by using differing lengths. A gear is simply multiple levers arranged in a circle

Gears

Any ideas of what kind of belts and pulley's would cope with the speed of a router?

Originally Posted by HypnoToad

Maybe I didn't explain it right, but you are right you would have a mechanical advantage or more torque of a ratio of 2 in to 3 out which would effectively give the router 1/3 more torque (gears or pulleys its the same) at the same time lowering the speed to where you could use larger bits like the panel cutters at optimum revs:

Sure but even on a fully optimised setup there's no advantage as the cutter only goes around 2/3 as often so it does not present the blade edge to the wood as often so while it can take a deeper cut it will only end up removing the same amount of wood per unit time. With the high revs you need more passes, with the lower revs you need fewer passes but each pass takes longer so theres no real advantage.

To remove more wood at the same rate in any wood working machines including a router style device requires more power which cannot be magically be made from less power. This is why they invented spindle moulders. They use 4+ HP 415V 3 Phase motors and very large bits to completely form complete profiles like window frame and stair balustrade in one pass. They are extremely good at high speed amputation of fingers and hands.

Any ideas of what kind of belts and pulley's would cope with the speed of a router?

Humm 20000 rpm, belts, pulleys and pulleys, that's F1 territory.

I built a thin kerf metal cutting saw that uses a "multi-V" belt and pulley that runs up to 12000+ rpm. While I'm no expert mechanical builder things get pretty hairy above these sorts of speeds.

Originally Posted by BobL

Sure but even on a fully optimised setup there's no advantage as the cutter only goes around 2/3 as often so it does not present the blade edge to the wood as often so while it can take a deeper cut it will only end up removing the same amount of wood per unit time. With the high revs you need more passes, with the lower revs you need fewer passes but each pass takes longer so theres no real advantage.

To remove more wood at the same rate in any wood working machines including a router style device requires more power which cannot be magically be made from less power. This is why they invented spindle moulders. They use 4+ HP 415V 3 Phase motors and very large bits to completely form complete profiles like window frame and stair balustrade in one pass. They are extremely good at high speed amputation of fingers and hands.


Humm 20000 rpm, belts, pulleys and pulleys, that's F1 territory.

I built a thin kerf metal cutting saw that uses a "multi-V" belt and pulley that runs up to 12000+ rpm. While I'm no expert mechanical builder things get pretty hairy above these sorts of speeds.

Seems like my idea is better in theory than operation, and the fact we are talking about 20,000 + rpm is the stumbling block. Thanks for your input.

I like to explore ideas and invent things, better put this with the flux capacitor I nearly perfected.

Originally Posted by HypnoToad

I like to explore ideas and invent things, better put this with the flux capacitor I nearly perfected.

I'll add it to my list - I have quite a few.

Originally Posted by BobL

[/COLOR]Even a basic 3Phase motor driven by a VFD can generate full power from 50 to ~120 Hz. Specially designed water cooled spindles as used on CNC machines running on vector controlled VFD can get close to full power across an even wider frequency range. I see that some members are already getting into this space.

I just watched this video and have noticed these are getting cheaper on Ebay so a 2.2kw spindle motor and VFD could be the ticket, they will probably get even cheaper when they get more popular.

Anyone on here using them and how do they perform?

https://www.youtube.com/watch?v=S_fJueCEAnc

What’s the largest ER collet the spindle will take?


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Originally Posted by jack620

What’s the largest ER collet the spindle will take?


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Not sure what the largest is but the ER20 that comes on the 2.2kw ones seems to be up to 12.7mm / 1/2".

If anyone has one they may be able to answer this.

Originally Posted by HypnoToad

Not sure what the largest is but the ER20 that comes on the 2.2kw ones seems to be up to 12.7mm / 1/2".

If anyone has one they may be able to answer this.

ER 20's metric can reach 13mm
Imperials reach 1/2"
Typical range at each size is 1/32"

Hi Everybody,

Sounds like a problem that would appeal to "Supernerd" aka Matthias Wandel https://woodgears.ca/ see also his YouTube channel [website has link].

cheers

Originally Posted by D-Type

Hi Everybody,

Sounds like a problem that would appeal to "Supernerd" aka Matthias Wandel https://woodgears.ca/ see also his YouTube channel [website has link].

cheers

That guy is a legend, I thought I came up with some ideas but Matthias takes it to a whole new level.

He’s definitely a creative bloke but I cringe at some of his MDF/Plywood machinery. They’re dangerous enough in their usual form, last thing I’d want to do is introduce even more possibilities for injury.

With his skills he could easily pick up some old woodworking machines and bring them back to life but I guess it’s more about building a machine for him than fixing one.