Norris A5 - question about the adjuster mechanism

[baldpate]

Hi everybody,

I recently achieved an ambition I have had for some while, when I managed to acquire one of these planes at a price I was prepared to pay.

It's nothing special - a somewhat battered post-WWII model which has obviously been well used. It seems basically OK, however : original Robert Sorby iron, adjuster runs freely (but see my question below), woodwork sound enough - just needed a clean & some work on the cutter.

But there's one thing I'm find puzzling, which I hope someone with knowledge of/access to this type of plane can help me with.

In order to get the blade JUST projecting below the sole, as you would want for smoothing, the cap iron must be positioned on the blade as far forward as it can conceivably be (fair enough !), AND the adjuster must be wound up to its maximum extend. I mean MAXIMUM, so there is no thread left below the rotating threaded hub (the part of the mechanism which connects to the body). This makes adjustment extra tricky, as I'm working at the very end of the total range. In effect, there must be something like 1 cm of usable thread above the hub which seems to serve no useful purpose.

The problem is that the distance from the front edge of the cap iron to the centre of cap iron screw is pretty much the same as the distance (along the bed) from sole of the plane to the centre of the ring at the end of the adjuster (which captures the cap iron screw head) when the adjuster is fully withdrawn - about 6cm on my plane. If that distance on the cap iron were even 5mm shorter, then I would be working the depth adjuster nearer the middle of its thread range, and adjustment would be that much easier.

The cap iron seems to be the original one, so I'm puzzled. Why would a plane otherwise so carefully crafted have such an obvious defect? Is there anyone out there with a similar (late) model who can tell me if theirs has the same 'feature', or can shed any light on it. Any information/observations would be gratefully received.

Thanks

Chris

 

[rxh]

Chris,
Any chance of a photo or two? That would make it easier to understand your problem.

 

[katellwood]

If that distance on the cap iron were even 5mm shorter, then I would be working the depth adjuster nearer the middle of its thread range, and adjustment would be that much easier.

The cap iron seems to be the original one,

Thanks

Chris

That cant be the right cap iron, I've just checked mine, when fully wound back the blade cutting edge is approx 3-5mm within the plane body when wound fully forward there is approx. 2-3mm cut shown below the sole

If it is the correct cap iron then there may be an issue with the adjuster. I've not stripped mine down but if memory serves doesn't the bango piece at the base of the adjusting screw, screw into the main adjusting screw (with the brass nut on the top) with a left hand thread. (i.e. the main adjuster has an external right hand thread and an internal left hand thread to facilitate forward and backward movement)

What I would check is without the iron in place screw the adjuster as far back as the threads allow. Then check to see if there is any exposed thread where the banjo screws into the main screw. If there is then at some point the adjuster has been removed and the banjo screwed out without the main screw being rotated in the internal thread that attaches to the plane body. If this is the case then the banjo hole will be further forward than should be when the adjuster is fully screwed back.

if all this checks out then the cap iron is not original and if possible may need grinding back 2-3mm to make the plane usable

As identified pictures would help

 

[AndyT]

There is a detailed description of the adjuster here which might be useful

http://www.antiquetools.co.uk/articles/norris.htm

 

[katellwood]

Interesting read

Thanks Andy

 

[baldpate]

Thanks for the link, Andy - it identifies the mechanism by which the banjo ring is attached to the adjuster shaft (it is 'floating', not the older type with the internal thread), and that helps solve part of my puzzle (see below).

Here are some pictures.

This first shot shows the sole of the plane with the blade adjusted to take a fine 'smoothing' cut. As I said, it's possible to achieve this setting - just tricky.

Without changing the setting, I unscrewed the lever cap and withdrew the blade assembly, which you can see in the next shot. It certainly looks like an original cap iron, rxh.

Here is a shot of the business end of the blade. You can see how close I've set the cap iron to the edge of the blade - with this camber on the cutter I couldn't get it closer.

Now here is where it got interesting. This is a shot of the business end of the adjuster, just after I removed the blade assembly. Unlike what I had previously seen, I can now see a bit of thread below the rotating hub - maybe 1mm (previously I'd seen none when I did this). I hope you can see this in the image.

After reading the article posted by Andy, I was prompted to look more closely at the banjo ring. I discovered there is a fair bit of play in the direction if the axis of the adjuster shaft - almost as much movement as there is exposed thread in the shot above. In the previous shot the ring is hard up against the shaft end. In the next image I have pushed the banjo ring downward to try to show the extent of the play - you may just be able to make out the gap between the end of the thread on the shaft, and the collar of the banjo ring.

In this latter position (with the little gap opened up) the banjo doesn't rotate freely - it is very stiff when rotating the shaft anticlockwise (blade retraction). As long as I pull upwards on the blade assembly when retracting the blade, the adjuster works quite smoothly.

So I now have an explanation as to why adjusting the depth of cut seemed such a hit & miss business, & I have a technique for doing it now. But I'm still left puzzled as to why the cap-iron and adjuster should be so configured that fine adjustment is being done at almost the limit of the range. As rxh reports,

I've just checked mine, when fully wound back the blade cutting edge is approx 3-5mm within the plane body when wound fully forward there is approx. 2-3mm cut shown below the sole

on his plane the fine adjustment happens at pretty much the mid point of the range (although his sounds like an earlier model).