Thread: problem with a 4&1/2 plane

Originally Posted by lightwood

adjust your back iron to the correct shape, so that when the hump of the back iron is pushed down onto the blade by the lever cap, there is just enough spring to get a firm contact on the cutting blade with the front edge AND ALSO THE BACK EDGE OF THE HUMP. A very common fault propagated by the hand plane guru brigade is to just bend it to get a firm contact with the front edge only. This is WRONG. It places a spring, or curve in the blade. So contact with the frog is only at the heel of the the bevel, and the top of the blade.
The back of the hump must bear down on the blade making good contact with the frog, otherwise the leverage resulting from the front edge of the blade with a pivot point at the heel of the bevel, is huge when only supported way up the top of the blade. When the blade starts to cut, a chatter can easily be induced.

This is often the reason that, from a group of planes, one is found to work better than all the rest. I have had thousands of Stanley type planed through my hands, and only a handful have had a properly adjusted back iron.
I believe a majority of the proponents of the thicker blade for a Stanley plane have little knowledge of the actual workings of this combination of blade and back iron and its proper adjustment They promote a thicker blade to solve a problem evidenced by bad adjustment of the back iron.
This was first patented in Dec 24, 1867 to make the thin blade in the plane function as a thicker blade does. It is worth a read.
Here is the patent by L. Bailey for this design of the back iron.

Regards,
Peter

I'm gobsmacked. Why is this the first time I've seen this explained?
It seems obvious now.
Thanks heaps Peter.
I'm off to the shed to check all my back irons.

Best wishes

Steve

Originally Posted by Pac man

To aid the discussion and my learning the photos of the cap iron and blade are below.

Pac man,
on the back iron, measure accurately the dimension from the front edge to the top of the adjuster slot, and let us know how much different it is than 101.0mm.
I just measured twelve, and got 101.0 - 101.5 mm. I think it might be useful to know how far away yours is...if at all....
I don't have a UK plane using one of these (sold them), but I still have a couple of blade sets with HSS blades that I used to interchange in them as needed.
These all fit into my USA planes which use that size blade.
Regards,
Peter

Originally Posted by stuffy

I'm gobsmacked. Why is this the first time I've seen this explained?
It seems obvious now.
Thanks heaps Peter.
I'm off to the shed to check all my back irons.

Best wishes

Steve

Steve,
Thanks.
Here are a few pictures of a new Stanley blade (as supplied) and an original blade side by side.
And fitted up to the same plane. Note the daylight under the new blade!
Attachment 203850

Attachment 203852Attachment 203851
Regards,
Peter

Lightwood
Pac man cannot measure this particular cap iron pictured as it is in my garage at the moment. I will measure it as soon as I get home.

So, does the distance between the top of the depth adjuster and the base of the plane vary much between stanley planes from all continents?

Thanks for that alternate view. It may save a lot of faffing about.

Originally Posted by pampelmuse

Lightwood
Pac man cannot measure this particular cap iron pictured as it is in my garage at the moment. I will measure it as soon as I get home.

So, does the distance between the top of the depth adjuster and the base of the plane vary much between stanley planes from all continents?

Thanks for that alternate view. It may save a lot of faffing about.

Woops,
I got you two mixed up, sorry.
There isn't much difference in the planes usually.
However I've had a couple of planes suffering the same complaint you describe. Back a while we had a another forum member with a #10 that had the same problem. The blade failing to retract.
When I've had the problem I just make certain the fog / body mating surfaces haven't been mucked around with. Select a cap iron from the box of bits and pieces with the shortest distance, and if that fails, just file about 0.5 - 1.0mm of the end of the cap iron and re-shape it nicely. ( I do file jewellery for a real job, so can do it pretty accurately.)

If the one you have is at the long extreme, and I have one shorter, you are welcome to have it. However, if you are ok with using a file, it might be worth the exercise to get it right yourself.

Regards,
Peter

Originally Posted by lightwood

The blade failing to retract.
When I've had the problem I just make certain the frog / body mating surfaces haven't been mucked around with.

That was my immediate suspicion. But the frog still has the original machining marks on the mating surfaces so it hasn't been ground down at all by a previous owner.
Unfortunately I don't have much of a 'boneyard' of planes to dip into. I was given a small box of plane parts of which the 4&1/2 was the most able to be reassembled but it was missing the blade, cap iron and screw. Whenever I see plane parts on ebay that I need they are all either in amongst a whole lot of other things I don't want or are so expensive on their own with postage that it would be better value buying a complete plane. Unfortunately, I don't have time to sort through garage sales, market stalls or swap meets to pick up parts.

Originally Posted by stuffy

I'm gobsmacked. Why is this the first time I've seen this explained?
It seems obvious now.

Yes me too. I've alway thought the bent cap-iron was a poorly considered, chatter inducing design. But thanks to Peter I now understand how these cap-irons are supposed to work. It makes sense.

Thanks.

Cheers, Vann.

pampelmuse,
just found the previous one..
It was a #10 1/2
Back in Sept 2008....where has all that time gone

https://www.woodworkforums.com/f152/i...-expert-79695/

Regards,
Peter.

Peter,
Appears this is very similar to mic-d 's problem. The offending cap iron is now known to sit outside your population distribution (n=12) at a whopping 102mm to the back of slot. I also measured my Carter #7 blade at 101mm.
You wrote "File 0.5mm off the edge of the back iron, and then reshape it to the original curve."
Given the cap iron is approx 1.5mm thick, removing 1mm of material off the top of the front of the cap iron would make the leading edge somewhat thinner at 0.5 mm. Am I am right in assuming his will not affect performance? I am leaning toward this method as it will maintain the height of the cap iron from the blade.

The alternate approach in my mind would be to grind back 1mm perpendicular to the front and then file off the bottom of the leading edge until I meet the junction of the ground edge and the rounded leading edge. Thus the cap iron will sit very slightly lower to the blade but still be 1.5mm thick at the contact point with the blade.
This is probably semantics and may make no difference but I am deferring to experience here.

Incidentally the carter cap iron has an odd flattened section (i.e. Leonard Bailey's patented second bend is quite a long way back from the leading edge).

Originally Posted by pampelmuse

Peter,
Appears this is very similar to mic-d 's problem. The offending cap iron is now known to sit outside your population distribution (n=12) at a whopping 102mm to the back of slot.

The alternate approach in my mind would be to grind back 1mm perpendicular to the front and then file off the bottom of the leading edge until I meet the junction of the ground edge and the rounded leading edge. Thus the cap iron will sit very slightly lower to the blade but still be 1.5mm thick at the contact point with the blade.
This is probably semantics and may make no difference but I am deferring to experience here.

pampelmuse,
That sounds like a good idea.
If the heel of the hump isn't about 1mm above the cutting iron, at rest, you can arrange a couple of battens in a vice and give it a bit of a squeeze to get that small clearance. (See the picture in a previous post.)
The other important thing to note is, make certain your flat on the front bottom edge of the back iron doesn't rise up and open when the lever cap is tightened on it....creating a shaving trap. I use a flat file in soft jaws in the vice, and cut a slight back angle.
Good luck,
Peter

Just to close out this thread I thought I would report on my manipulation of the cap iron. It was a quick fix and took 10 minutes. I marked along the underside with a blue marker pen which left a mark about 1mm wide and then filed down to the line, followed by filing the underside as Peter suggested. I then smoothed the rounded front a little by running it over some abrasive paper on a hard flat surface. Stuck it back in the plane on top of a sharp blade and it worked fine. Knowing the recent history of the plane I would say that it is probably at least 20 years or more since it has been used so it is great to see it back to functional state. (Thanks for everyone's assistance)
The plane is cetainly not a thing of beauty as I haven't removed the rust on the sides or body (the japanning is all gone).
Attachment 204991
As you can see from dark line across the timber I did an epoxy repair on the tote which was cracked and the epoxy also filled some nail holes from a previous attempted repair' I tried to clean up the knob at the front but it was pretty badly stained black from rust so it will have to remain darkened. I did a bit of flattening of the base with a coarse diamond stone and as you can see from the staining pattern on the base there is a slight concavity at the centre near the toe and heel but round the mouth it is flat enough.
Attachment 204992
Their is some advanced pitting near the heel as well but it is only a cosmetic imperfection
Attachment 204993
But does it plane? Hell yeah! I tried it on a few different timbers and it left gleamingly smooth finishes on all of them. It even made short work of some highly figured apple box I am making into a panel for a lid.
Attachment 204994
My one query is that longer shavings come out of the mouth in a concertina fashion rather than as curled rounds. Is this a function of the shape of the front of the cap iron or are they catching on rough metal?
Attachment 204990

Good job
Can you please post a pic of the cap iron from the pov of where it meets the blade and the top where the curve is as this may help

Originally Posted by pampelmuse

......My one query is that longer shavings come out of the mouth in a concertina fashion rather than as curled rounds. Is this a function of the shape of the front of the cap iron or are they catching on rough metal?

pm, that usually indicates either chips getting under the cap-iron, catching on the cap-iron because it has a slight gap, or having the cap-iron set too close. If you dismantle the cutter/cap-iron after some use & find fine wood chips fall out, you know they are not properly mated. Put the assembled cutter/cap-ron under a bit of pressure in your vise & either check with the light behind it or a feeler gauge to see if there is a slight gap at the tip. This is quite a common problem, I find - the end of the cap-iron may look flat & sharp, but is either slightly rounded, or not filed back at a sufficient angle, & when it comes under pressure, it lifts the front slightly, creating a tiny gap which induces the symptoms you described. I finish off my cap-irons after filing on a diamond stone, to ensure the tip is dead flat and straight - it needs at least as much care & accuracy for this part as for your blade bevels. Polishing the curved top of the cap iron so that it is nice & smooth - at least to 400 grit W&D - also makes a noticeable difference.

I also reckon, contrary to some recommendations, that cap-irons can be set too fine, particularly in your average clunker. A "fat 32" back from the blade tip, was what the old blokes I worked with used to say. (That meant a touch more than a 32nd of an inch - I'm too lazy to do the conversion to metric... ). This should be plenty close enough to pre-tension the blade. If you set too close to the cutting edge, it will impede smooth exit of the shavings.

Cheers,

Seems like the closeness to the blade edge could be the issue. I put it real close just so I could get maximum adjustment on the blade. This is the blade/cap iron as taken out of the plane.
Attachment 205004
Attachment 205005
The cap iron seats on the blade well. The front is smooth albeit a little stained. I will attempt to back it off a little to 1/32 (or approx 0.8mm) to see how it runs* and maybe then smooth the front with some W&D to get it slicker.

*Edit: Just tested this and it seems to have lessened the folding up of the shavings.