The clutch motor....

[Dakotanorth]

I am slowly training up on the Pfaff 345 I recently bought from Chris.  It is a great machine, and it works much like my household machine from the 1950's.

I'm still struggling with the clutch.  I get the classic sequence:

Nothing...nothing...nothing,,, it starts to vibrate....WHAM!! It takes off at 1000spm.  I  have been able to soften this a bit by rolling the wheel by hand, as the motor starts to move the needle, but that sometimes requires 3 hands.

What's the verdict on using pulley systems to reduce the speed?  Are Servo motors big bucks?

[GPaudler]

I put a servo motor on my Pfaff 335 without a speed-reduction and it works great. I've bought three from Alberoni's (in Orange County) eBay store or listing for about $115 with free shipping. Plenty of other merchants, as well. They are designed to mount easily in place of the standard clutch motor. If $115 doesn't hurt, you won't be sorry and you could spend that, or more, monkeying with a speed reducer trying to get your clutch motor to behave.

[dikman]

It might be worth dismantling the clutch and checking the condition of the clutch material and making sure it's smooth and the facing plate is clean and smooth, BUT it takes a bit (a lot?) of practice to learn to control a clutch motor, particularly if you want to go slow for leatherwork. You could fit a smaller pulley to the motor and fit a speed reducing pulley setup, but for a newcomer a servo is probably the way to go, as it will give you control and inspire confidence.

[MADMAX22]

If you stack foam or similar under your pedal it helps to ease into it, wont be the same as a servo without the speed reducer. That being said a servo really needs a speed reducer to go slow because of the loss of torque at slow speeds but its more manageable overall. 

You can replace the pulley on the clutch motor cheaply as it probably has like a 3" pulley (or bigger). 

A clutch motor should have a little bit of a sweet spot that allows you to slowly roll into it. Dikman is right about checking it out some. 

[CowboyBob]

Alot of times the

cork dries out,we have always told people to smear about a teaspoon of grease on the clutch pad & run the belt as loose as you can!

[Uwe]

Personally, the only clutch motors I like are the ones attached to fancy Efka controllers. Unless you have some nostalgic attachment to plain clutch motors, there's really no need to subject yourself to them. 

Even a $115 cheapo servo motor with a small 2" pulley will make a world of difference. For around $200 you can buy one of my personal favorites, a Sewpro 1,100W servo motor with plenty of low-end torque and very low 100rpm starting speed (most other servo motors start spinning with 300 rpm.)

[Gregg From Keystone Sewing]

On 2/12/2017 at 6:03 PM, Dakotanorth said:

I am slowly training up on the Pfaff 345 I recently bought from Chris.  It is a great machine, and it works much like my household machine from the 1950's.

I'm still struggling with the clutch.  I get the classic sequence:

Nothing...nothing...nothing,,, it starts to vibrate....WHAM!! It takes off at 1000spm.  I  have been able to soften this a bit by rolling the wheel by hand, as the motor starts to move the needle, but that sometimes requires 3 hands.

What's the verdict on using pulley systems to reduce the speed?  Are Servo motors big bucks?

....And that's what we call a jackrabbit start, this occurs when the belt is too tight.  Easy to do on the longer post bed machine drive belts.  If the belt is too tight, it will go from 0 to 60 in no time, with very little in between in terms of a power band.  Try backing off on the motor belt tension, this should help.

Also...if the clutch lining (cork) is worn, or glazed over, this could be an issue, as well.  Taking off the end bell of the motor to expose the cork, you can hit it with some light sandpaper to break off the glaze, and then put a thin layer of axle grease (we use Castrol multipurpose wheel bearing grease here).

These two things may help go a very long way to getting the motor under control.  Again, we like to sell servo motors as replacements, but people have been successfully doing may things on machines like these with standard clutch motors for many many decades without too much issue.

[Dakotanorth]

Thank you everyone.  I appreciate the help and insight!

Slowly I am getting used to the clutch motor.  A trick I learned with my home machine is this:

IF the power is turning the wheel, but it looks like it might "jackrabbit" start, then I start to hand crank the wheel.  Just a touch; just enough to break the tension and move it.  The instant it does I put my hand back onto the work.

I'm also learning to drive it barefoot- I use my toes and curl them over the end of the plate to apply a slight amount of pressure.  Your toes aren't that strong, so it's hard to apply too much force!

 

[JimTimber]

I've been barefoot the whole time with mine and despite nearly 20 years of pedal control from TIG welding, I still don't like how binary the inputs are with the clutch motor.  Fortunately, my servo shows up Thursday and I'm getting itchy.

[Cascabel]

My personal cure for that problem is to apply a suitable amount of pressure on the hand wheel with my right hand, sort of like a brake to slow things down, if need be.  It helps a lot to have a huge wheel on the machine, and a small pulley on the motor, like what I have on my 42-5.   Very easy to control that way