No.5 jack plane blade advancement issue

[Jacob]

Well tibi, you have learnt some valuable lessons on cap-irons, so you haven't wasted your time.

The situation you described is pretty commonplace on old planes. I think Stanley et al deliberately made the cap-irons so that most of the CI sits flat against the blade when screwed together and the curved end puts sufficient pressure on the mating edge. This causes no or minimal flexing of the blade iron. The trouble starts when for various reasons, you need to re-seat the end of the cap iron on the blade. You don't have to remove much to find you're no longer getting firm contact with the blade. This is easily cured by bending the cap-iron just a little - old cap-irons are thin & "soft" steel which is pretty easy to bend. But do it carefully, if you over-bend the curve you can get into a situation where you've shortened the CI & you run out of depth adjustment - it's all very finely calculated and you don't have to alter the edge-to-cam-slot distance by much to get into trouble, as you've discovered.!

I really like the old-style cap-irons, they use a minimum of material but the design allows them to work very well. It's a well thought-out mechanism, I reckon. If everything is fitted properly, the cap-iron & blade should pull together with no or minimal bending of the blade when the retaining screw is tightened, but apply sufficient pressure to close the end securely against the blade. It doesn't need a lot, the lever cap pressure will add a bit more & it should be plenty enough for normal use if everything is right:
View attachment 119596

The trend started a few years back to make very heavy replacement cap-irons, the idea being to add more stiffness to the blade/cap-iron assembly. The cap-irons are similar to the ones used with very heavy blades on old planes, they have a single bend to bring the edge to bear against the blade. This it does, for sure, and there is no problem with thick blades, particularly the very thick blades of old, but they don't work so well with the thin Stanley/Record blades, imo. When tightened down, these caps can put a very distinct curve in the blade!
View attachment 119595

The lever-cap won't 'straighten' something like this, it only applies pressure at top & bottom of the assembly, leaving all or most of the curve intact. This may or may not matter - depending on the type of wood you plane & how heavily you're cutting, you may not notice anything untoward, but I've found it can certainly promote a tendency to chatter in some situations & I think is best avoided - better to have it so the blade assembly sits nice & flat on the frog.

So when tinkering with cap-irons, there are a few things you need to keep in mind....
Cheers,
Ian

The Stay-set cap iron seems to work well but that has its quirks too. Best is that it doesn't bend the blade and applies the pressure from the lever cap to the edge, the middle and the top under the cam. Three points.
It's not just the staying set which is (slightly) useful but also the 3 point solution to all the probs IWW points to above.
Out of many odds and ends I've bought and turned over for years the Stay-set cap irons are the ones which I won't be putting back on ebay!
PS then there is the Millers Falls two part lever cap The Millers Falls Two-part Lever Cap - the small workshop which also has the 3 point idea but differently. No modern versions being made however.

 

[IWW]

The Stay-set cap iron seems to work well but that has its quirks too. Best is that it doesn't bend the blade and applies the pressure from the lever cap to the edge, the middle and the top under the cam. Three points.......

Jacob, I don't know how you manage to get your Bailey type lever-caps to apply pressure at 3 points? The retaining screw is a fulcrum point & counters the pressure under the cam-lock & the toe. In my understanding, pressure (on the blade assembly} is applied at those two points only.

The Millers Falls LC does apply pressure at 3 points, for sure, thanks to the hinged toe piece. Never used one myself, so can't speak from experience, but I suspect it's another solution to a problem that doesn't really exist if the frog is well-machined & the blade/cap-iron assembly is set up properly (as shown above). An ordinary LC holds it all together quite adequately on my old Stanleys. I plane a lot of harder woods than most of you folks are used to and blade chatter is definitely not an issue for me. The original blades have long since gone to god & been replaced by thicker after-market blades, but even with the original blades I don't recall chatter being a problem. Not so for an el-cheapo #3 I bought in a very foolish moment, forgetting the maxim "you get what you pay for". It had the frog seated at one point only, on very roughly machined surfaces; the toe of the frog did not touch the sole at all. That plane & I never did get on!
Cheers,
Ian

 

[Jacob]

Jacob, I don't know how you manage to get your Bailey type lever-caps to apply pressure at 3 points? The retaining screw is a fulcrum point & counters the pressure under the cam-lock & the toe. In my understanding, pressure (on the blade assembly} is applied at those two points only.

....

The retaining screw is one pressure point which converts to two pressure points at each end of the ordinary lever cap which converts to 3 pressure points - at each end of the stay-set 2 piece cap iron and the point where they lap in the middle.
It's a better design than the Millers Fall lever cap and does the same thing - they both effectively have a hinge in the middle.
Stay-set is nice to use and very solid.

 

[IWW]

Hmm, your analysis of forces & mine give some different results, Jacob.

With a standard lever cap, pressure is applied on the blade assembly at two positions, the toe & under the cam. The force on the retaining screw is the sum of these two forces in the opposite direction.

I've only ever used two 'stayset" cap irons, a Record 'original' and the one on my Clifton so my experience is very limited, but I would think the details are the same for all. On both of my cap-irons, the main body sits flush on the blade when screwed together, there is actually no pressure on the loose end-piece at this stage (you can lift it on & off easily without loosening the screw). The toe piece is not pressed against the blade until the lever cap is locked down. Pressure application & distribution is then essentially the same as for a bog-standard cap-iron. The only difference is you don't cause any flexing of the blade when the two irons are screwed together. As mentioned, slight flexing may or may not cause any discernible effect on performance - I'd wager London to a brick that your average punter would not detect it in a blind trial, all else being equal, so it's a moot point that the stayset CI has any genuine advantages over the original Bailey/Stanley version. If you ask anyone who's lost that silly little end-piece in the shavings, they'll most likely say it doesn't!

The Millers Falls lever cap does apply pressure on the blade assembly at three points (four if you want to be pedantic, since there are two little lugs that bear on the cap-iron at the back of the hinged section). Again it's moot that it confers any real advantage to performance. I've never used one so I should withhold judgement, but I seriously doubt I'd notice a staggering difference compared with a single-piece lever cap.

There is too much subjectivity in assessing tool function; you are likely to feel that a tool performs better because it has a design feature that you think is "a good idea" (& vice-versa!), but as you know, there are many factors that need to work together to make a plane an excellent tool, & I maintain that if you pay attention to the details that matter on a bog-standard Bailey, it will perform as well as any plane fitted with a "stayset" type cap-iron or a Millers Falls type lever cap.

I may be dead wrong, but it'll take a good double-blind trial that shows a clear difference to convince me......
Cheers,
Ian

 

[Jacob]

Hmm, your analysis of forces & mine give some different results, Jacob......

More about it here The Record Stay-Set Cap-Iron - the small workshop

you are likely to feel that a tool performs better because it has a design feature that you think is "a good idea" (& vice-versa!),

Not me squire! I'm totally suspicious of all the offering and good ideas thrust before me, having tried a few and having passed them over. You'd be amazed at the things I've passed on to Ebay!!

......I maintain that if you pay attention to the details that matter on a bog-standard Bailey, it will perform as well as any plane fitted with a "stayset" type cap-iron or a Millers Falls type lever cap.

Yes can be perfect but often problematic with old planes and swapped pieces - bent blade being most common due to shape of cap iron, resulting in blade not quite seated on frog in the middle. The Stayset avoids this - once the lever cap is off there is no pressure on the blade from the cap iron.
PS there are heavy weight one piece cap irons for sale but these are bad news as they can bend a thin blade so that it doesn't seat well. The StaySet is heavy but the two piece design avoids this problem and the flat upper half also gives better clamping.

 

[IWW]

Jacob, I think we've reached a Mexican standoff, so let's agree to disagree once more.

But do have a little think about the mechanics of a Bailey frog/blade sometime & you may see that this statement (from the site you linked to): " The Record two-part cap iron changes the way the cutter is held to the frog by adding pressure at 3 points, rather than the normal two in a standard bailey plane, thus doing what Bailey had originally intended..." is just plain wrong. The blade assembly is held against the frog by the lever-cap, which applies pressure at two places only. A SS cap-iron does not & cannot change this fundamental relationship!
I'll leave it there.
Cheers,
Ian