Dieter Schmid's Fine Tools

ECE Primus Reform Smoothing Plane - Operating Instructions

Primus Reform Putzhobel von ECE


How to adjust

Choose the desired cutting depth with a turn of the adjustment screw and your E.C.E. PRIMUS plane is set to go. There is no free wheeling of the screw. It's tight and sure, like rack and pinion steering on a sports car. You'll notice that the plane iron stays sharp a long time.

Removing the blade

  1. Turn the adjustment screw backward slightly.
  2. Loosen the tension screw nut at the back of the plane body. (Do not remove).
  3. With your fingers, take hold of the opposite end of the tension screw in the chip box and turn it 90°.
  4. Lift the lower end of the plane iron off the tension screw and gently draw it out of the body of the plane.

Replacing the plane iron

  1. Insert the plane iron into plane's body, reversing the action of removal.
  2. Turn the end of the tension screw 90° so the cross pin again lays between the cams of the plane iron cover. The red marked part of the tension screw with the words "oben/above" must be visible over the top of the cross pin.
  3. Tighten the tension screw nut slightly
  4. To check tension, align the cutting edge of the iron with the plane's sole by mooving the regulator lever right or left. Re-tighten the tension screw nut, if necessary.

This is what our customer Peter Austin in Devon, UK wrote:

I think this is going to be a fabulous plane once I get to know it properly. I tried it "out of the box" on my beech workbench-top and the wood shines! The 50 degree blade angle suppresses tear-out and there is zero backlash when adjusting the blade.

After taking it apart, I have only just realised how it works. The instructions tell you how to adjust the plane, but not why it works. The diagram is clear, but again, there is no explanation as to why it works. I think that E.C.E. have assumed that "Well, there is a clear diagram, it's obvious how it works. It's a brilliant plane, we will just wait for the orders to come in".

The give-away that there is some shortfall in customer knowledge is an extra piece of paper included in the package headed "Additional instructions to adjust the plane iron parallel to the sole". But, again, they do not tell you why you should need to do this except that you need to do this after turning the tensioning screw nut.

If you'd like to be bored, please read on. I shall attempt to explain how this plane works - if only to get it clear in my mind:

Look at the diagram on the above web page headed "Operation Instructions for the E.C.E. Primus plane".

At the back of the planebody, there is a knob. The knob is attached to a piece of steel that is in turn attached to the plane blade via the chipbreaker. The piece of steel is always in tension - through the use of a large spring just behind the knob - and is trying to pull the plane blade back against the blade-bed. However, since the blade-bed is at 50 degrees, the effect of this tension to to force the plane blade upwards away from the plane-base. This is where the chromed adjusting knob comes into play. This is attached to a threaded rod whose far end presses down onto the piece of steel under tension.

There is enough vertical give in the assembly to allow the chromed adjusting knob to raise and lower the blade. The clever trick is that this assembly is always in tension and so there can never be any backlash ie. slack. After a number of turns of the chromed adjusting knob, the tension in the piece of steel attached to the blade needs to be adjusted so as to keep the system in equilibrium.

Anyway, for now, the plane is in a thick polystyrene box in my workshop awaiting some serious use over the weekend. My first task is to dull the toffee-apple finish with some 0000 wire wool and wax. And then to introduce the blade to my 6000 grit waterstone.

(I want to thank Peter for his kind permission to publish this here. Dieter Schmid)

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