Why are we not seeing more VFD variable speed machines?

[Roger Feeley]

I just posed a question on another thread about how my 12” disc sander often runs faster than I would like. I would love to have a vfd variable speed motor on it like I have on my jet lathe. I wouldn’t consider a router without electronically variable speed and soft start.

I would also love to see a vfd drill press. In my case, my 40 year old drill press motor started acting up so I replaced it with a vfd drive. But my main question is still why we don’t see more electronically variable speed tools.

It can’t be cost alone. Festool’s success tells us that there are plenty of people out there willing to pay more to get more.

[Malcolm McLeod]

It can’t be cost alone.
Sure it can. Cost to redesign, acquire, build, program, test, package, stock spares, and of course - provide another world of customer service/support. =Cost alone.

[Richard Coers]

I just posed a question on another thread about how my 12” disc sander often runs faster than I would like. I would love to have a vfd variable speed motor on it like I have on my jet lathe. I wouldn’t consider a router without electronically variable speed and soft start.

I would also love to see a vfd drill press. In my case, my 40 year old drill press motor started acting up so I replaced it with a vfd drive. But my main question is still why we don’t see more electronically variable speed tools.

It can’t be cost alone. Festool’s success tells us that there are plenty of people out there willing to pay more to get more.

Technically a VFD does not change the motor into a variable speed motor, it controls a conventional 3 phase motor. Once you get up to a higher hp rated motor, the VFD cost goes way up. It also adds one more electrical component into the system that increases the chances for trouble. I assume you have seem plenty of lathe posts about "dead VFD and how do I program a generic VFD" because the OEM controller is too expensive. Personally I see plenty of variable speed tools. Router, drill, screw driver, pad sander, belt sander, grinders, hand held carving motors. etc....

[Mark Hennebury]

I think that I know the answer to your question.

Cutting and grinding Tools have A maximum safe operating speed dictated by the manufacturer of the tool.
Reliable Speed control is critical to your safety.
Manufacturers can promise speed control, that doesn't mean that they deliver it.
Believing that you have reliable speed control, when you don't, puts you in dangerous and possible deadly situations, totally unaware of the danger, and therefore unable to protect yourself. Ask me how I know?

I had my router mounted on my metal lathe with a small grinding wheel in it to use as a tool post grinder, for final polishing the last few tenths for precision fitting of bores and spindles. I have done this many times before. I set the speed control to #1. 8,000 rpm and started the router, It was not in contact with anything, just idling for a minute of so, when it the router shot up to full speed (24,000 rpm)causing the grinding wheel to explode, I was a few feet away at my bench, startled by the sudden noise, I turned just as the grinding wheel exploded. A chunk of grinding wheel the went through my face taking a chunk of bone with three of my teeth in it, and shoving it into my mouth.

Your results might differ from mine depending on the situation and tooling, but you might want to re-evaluate your trust in electronic speed control.

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https://youtu.be/pNhtXgBHijw

[Mark Hennebury]

Just in case anyone thinks this is just one router, I have checked a few of my other routers this month.


https://youtu.be/kYoEiwL-QCs

[John TenEyck]

You can have variable speed on any machine you can buy or retrofit with a 3 ph motor; just put a VFD on it. The problem becomes one of cost, especially once you exceed about 3 hp, as Richard pointed out. But you can do it.

I'm pretty sure Rikon or someone already offers a variable speed drill press.


John

[Brian Holcombe]

It’s my understanding that most induction motors are made to work within a narrow range of frequency, outside of this range they are running in a less that ideal state. I like a VFD for other aspects of programmability such as the ability to stop rapidly and react to overload very quickly.

When you need a broad range of RPM it seems that manufactures move up a combination of VFD and spindle rather than a standard induction motor.

[Greg Quenneville]

Also, as you decrease the speed you also lose torque. I use VFDs to give me a bit of speed flexibility, perhaps +/- 20% at the most.

For full speed and torque range you need something like a servo motor.

[Malcolm McLeod]

…

Cutting and grinding Tools have A maximum safe operating speed dictated by the manufacturer of the tool.
Reliable Speed control is critical to your safety.
Manufacturers can promise speed control, that doesn't mean that they deliver it.
…


You forgot operating a rotating tool w/o proper guards.

IMHO (and some experience), a router speed control circuit’s reliability ranks just below ‘wishful thinking’.

Hope you have successfully recovered from your injuries.

[Malcolm McLeod]

Also, as you decrease the speed you also lose torque. I use VFDs to give me a bit of speed flexibility, perhaps +/- 20% at the most.

For full speed and torque range you need something like a servo motor.

+1, but get out your wallet. VFDs + induction motors are an excellent compromise, in terms of performance, cost, and (limited) complexity.

[Monte Milanuk]

In a past job working with a variety of variable speed drives, some DC, some AC, one of the things that was becoming known at the time (20+ years ago) was the tendency for VFD operation to accelerate the breakdown of the winding insulation. It was simply the cost of doing business where I was at (large-ish steel mill, with it's own on-site motor rewind shop), but for a vendor supplying machine tools to consumer level clients... I can see that being a hard pass.

[Maurice Mcmurry]

Finding an affordable, decent, small, 3 phase motor has been the stumbling block for several conversions I hope to do. Hopefully the drill press will come first.

[Mark Hennebury]

Hi Malcolm, and thanks for the good wishes. I have healed up well.

Safety is not an accident.
50 years of working with dangerous machinery and power tools, one bad accident. Not the kind I expected, kind of thought maybe I would stick my hand in a jointer or table saw at some point, or get sucked into the big lathe.

I have used all manner and size of grinders pencil and die grinders, disc-grinders, bench grinders, up to massive 2500lb tool and cutter grinders, and surface grinders ( I have a 6" x 18" surface grinder in the shop) I have had automatic straight knife grinders for the Supersurfacer blades. etc..
I have stayed safe all these years, by relying on my judgement and leaving a margin of safety, a margin that I am comfortable.
There is no absolute safety, not for the living.
Everyone is different and responsible for themselves.
My judgement has worked well for me up until this accident, which got me, but you can’t account for every variable.
I have never worked under optimum conditions, I worked the best that I could with what I had.
I had bills to pay and work to get done, worked long hours, around the clock sometimes, so you work on the edge. I never had the luxury of turning the table saw off and waiting for it to stop, before removing the piece that I just cut.
You analyze, you make judgements, you focus, you commit, you hold on, and see it through.

What I do with my tools is up to me!
If Makita tells us the router has speed control, then it should have speed control!
They own us that much.








You forgot operating a rotating tool w/o proper guards.

IMHO (and some experience), a router speed control circuit’s reliability ranks just below ‘wishful thinking’.

Hope you have successfully recovered from your injuries.

[Rich Engelhardt]

Shoot - a A Makita 2+ HP plunge router is on my short list.
Figures.

That Triton is looking better all the time.

[Chris Parks]

For all the problems outlined earlier in the thread I have seen none and I have been around hundreds of VFD's. Make sure the VFD you buy has vector control and torque loss is minimised though not completely eliminated but enough that in most circumstances won't be a worry.

[Greg Quenneville]

Yes, in most cases. I bought my first ebay servo + drive for my metal lathe. My lathe originally had a 1960’s electronic drive with a speed range of 40-4000 rpm. The drive was burnt out, and the motor was a 200 lb behemoth. The servo also has the indexing feature which is useful on such machines.

Monarch 10EE lathes are similar, and owners wishing a VFD solution to the noisey motor-generator drives have to use a 10hp motor to have any useful low rpm torque.

More to the forum at hand, for woodworking I would find a VFD useful on any of my tools since, except for the shaper and drill press, all work in a fairly narrow range of speeds. My shapers get the belts changed with tooling changes, but most of my cutters require the same rpm anyway. I would not expect to have a useful speed range on a shaper without either a massive motor or the odd belt change. Or a servo.

As you have pointed out Chris a VFD would be very useful on a big impeller dust system.

I have installed VfDs on three milling machines, a lathe, bandsaws, gear head drill presses. If nothing else the soft start feature is very welcome. Three phase for the masses. What’s not to like?

Greg

[Jim Becker]

VFDs have been used for many years on wood lathes...pretty common actually other than at the lower end. They also make sense for tools like drill presses and VFD or other variable speed setups are the, albeit with few choices. I question how valuable they are for many other kinds of tools that generally work best at a single cutting speed, other than providing for use of 3 phase motors off single phase power where that is a need or desire on a per tool bases, rather than putting in an expensive RPC, etc.

[Mark Gibney]

Mark that's a shocking looking injury, looks like you went through the windscreen. Your recovery looks to be coming along well so that's good.

[Jared Sankovich]

More to the forum at hand, for woodworking I would find a VFD useful on any of my tools since, except for the shaper and drill press, all work in a fairly narrow range of speeds. My shapers get the belts changed with tooling changes, but most of my cutters require the same rpm anyway. I would not expect to have a useful speed range on a shaper without either a massive motor or the odd belt change. Or a servo.

Greg

I like vfds on shapers for fine tuning cutter speeds. It's nice to be able to dial in the speed to the material and cut. Sometimes a small change in feed speed and cutter rpm makes a big difference.

[Mark Hennebury]

Thanks Mark. I have healed up well, and the emergency doctor that sewed my face did a great job considering that it wasn't a clean cut.


Mark that's a shocking looking injury, looks like you went through the windscreen. Your recovery looks to be coming along well so that's good.