Veritas Large Router Plane issue and other planes Lever Caps

While participating in hand planes discussion on some non-English speaking forum, somebody has questioned material choice for the collar that holds the blade on Veritas Large Router Plane. That somebody claims to tighten the blade hundred times a day and that this high load eventually damages the thread in aluminium (aluminum) collar. And after that discussion went on regarding other parts on other hand planes from the same material and then to comparison to bronze lever caps on other well-known hand planes. My load is nearly absent and had no problem, so, I cannot relate to that.

I couldn't find any discussion about that but I'm sure there must be some reasons to choose one material over the other. Just wonder what they might be. On the other hand, Lie-Nielsen Router Plane has no aluminium parts.

I did find Derek's post about piston in the collar screw and mentioned it on that forum, maybe that is the actual problem...

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Originally Posted by Andrey Kharitonkin

While participating in hand planes discussion on some non-English speaking forum, somebody has questioned material choice for the collar that holds the blade on Veritas Large Router Plane. That somebody claims to tighten the blade hundred times a day and that this high load eventually damages the tread in aluminium (aluminum) collar. And after that discussion went on regarding other parts on other hand planes from the same material and then to comparison to bronze lever caps on other well-known hand planes. My load is nearly absent and had no problem, so, I cannot relate to that.

I couldn't find any discussion about that but I'm sure there must be some reasons to choose one material over the other. Just wonder what they might be. On the other hand, Lie-Nielsen Router Plane has no aluminium parts.

I did find Derek's post about piston in the collar screw and mentioned it on that forum, maybe that is the actual problem...

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The concern is nonsensical IMO.

Like many such rumors this one has some grounding in truth: Steel is more resistant to fatigue than is Aluminum, because Steel has what is called an "endurance limit", or a threshold stress level below which even an infinite number of load cycles will not cause fatigue failure. The thing you have to realize is that the endurance limit only come into play after O(1 million) cycles, as shown by this graph on the relevant Wikipedia page. Note how the blue/steel curve flattens out at ~29 kpsi load and ~1 million cycles (the red/Aluminum curve is lower than the blue/steel one at lower cycle counts simply because Aluminum isn't as strong).

I very much doubt that that part is handling 10s of thousands of PSI when tightened, so even with Aluminum it probably has a fatigue life measured in billions of cycles. In other news, Aluminum airplanes, bikes, and other heavily cycled objects work just fine as well.

I would guess that in this case damage starts with every tightening, otherwise it could not happen in less than a million cycles, as you say... But very interesting read, thanks Patrick.

Paul Sellers recently posted about special screw driver for tightening locking knob, and cutting a slot in it, pretty much like what Derek does to various Veritas knobs. So, unlike cap lever, there is some relatively high force required to hold the cutter. For me it works alright without screw driver but I learnt to remove backlash (?) by turning depth nut backwards after increasing depth of cut, pretty much like with bench planes but when decreasing depth of cut. In that case less force is required to hold it.

I think aluminium might be even for better - if iron rusts out, at least the cap levers will pass on to other generations. Just kidding :)

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Originally Posted by Andrey Kharitonkin

I would guess that in this case damage starts with every tightening, otherwise it could not happen in less than a million cycles, as you say... But very interesting read, thanks Patrick.

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If damage started with every tightening then that would mean that the part was under-designed relative to its static load requirements, never mind fatigue. I don't think that's the case here, as I suspect that that part is an order of magnitude stronger than it needs to be.

There is one factor we haven't discussed, namely galling. Aluminum is much more susceptible than steel or iron, though again I don't think this interface carries enough load for that to be an issue (and if it were a drop of grease or oil would kill the problem instantly).

It looks like the parts for that plane are cast aluminum. If so, the threads may not be so well suited for high torque. If the blade isnt held securely, the user will likely over torque the screw (maybe use a pliers) and strip the threads. Machined aluminum plate stock would be stronger but much more expensive.

What about bolt that goes into it, it is much harder and stronger than the collar. Could damage the thread or bend something and then leave some burr inside that would cause it to jam or to loose smoothness.

And then also there is dust and chips and other dirt that can get into the thread. That would act as abrasive.

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Originally Posted by Andrey Kharitonkin

What about bolt that goes into it, it is much harder and stronger than the collar. Could damage the thread or bend something and then leave some burr inside that would cause it to jam or to loose smoothness.

And then also there is dust and chips and other dirt that can get into the thread. That would act as abrasive.

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Sure, and as an engineer I could list a bazillion more ways in which that part could fail, but IMO the stuff we're discussing here is somewhere between "struck by lightning" and "obliterated by a meteorite" in terms of likelihood.

I'm sure that a sufficiently determined user could destroy that part with a large enough lever (pliers, whatever), but that would be abuse pure and simple. A determined user can destroy *anything*. The question is whether the tool can sustain the loads required for normal operation plus adequate margin, and I just don't see any issue here (full disclosure: I have one).

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Originally Posted by Patrick Chase

... I just don't see any issue here (full disclosure: I have one).

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Me too... I was very surprised to read about that. Let's wait, maybe there will be some pictures of failed part... Pliers could be involved, as user was also complaining about cutter rotating slightly sideways and that it was not practical to use optional fence because of that. So, probably he tried to tighten to death...

Quote:

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Originally Posted by Andrey Kharitonkin

Me too... I was very surprised to read about that. Let's wait, maybe there will be some pictures of failed part... Pliers could be involved, as user was also complaining about cutter rotating slightly sideways and that it was not practical to use optional fence because of that. So, probably he tried to tighten to death...

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Was he using a Veritas cutter?

The reason I ask is because the cutters for that plane have square shanks that register into a V-groove, such that very little force is required to prevent the cutter from rotating.

Quote:

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Originally Posted by Andrey Kharitonkin

......

Paul Sellers recently posted about special screw driver for tightening locking knob, and cutting a slot in it, pretty much like what Derek does to various Veritas knobs. So, unlike cap lever, there is some relatively high force required to hold the cutter. For me it works alright without screw driver but I learnt to remove backlash (?) by turning depth nut backwards after increasing depth of cut, pretty much like with bench planes but when decreasing depth of cut. In that case less force is required to hold it.

I think aluminium might be even for better - if iron rusts out, at least the cap levers will pass on to other generations. Just kidding :)

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Audrey, your earlier comment about the piston may be the issue, is probably spot on.

I have mentioned this a couple of time when someone comes along with a problem. Not that long ago, Paul Sellers posted his "fix" on his blog. This involved filing the adjusting knob so that the collar could be cranked down. He seems to enjoy this type of post, where he can "rescue" a tool, especially one which is a premium tool. It is a not-so-subtle put down, and what I dislike about his offerrings. He otherwise does fine work as a teacher.

I wrote in to his blog and explained that the piston ...

https://s19.postimg.org/vcy4lcq7n/Ro...psiha9zwvz.jpg

https://s19.postimg.org/vppirjg77/Ro...psppx7gdt6.jpg

... occasionally gets sticky and does not slide freely. Mine has never done this, but then I do clean my tools and lubricate moving parts with a little Renaissance wax. The fix is simply to jiggle the piston, and then lubricate it. Done. No modification of parts, and no special screwdriver (the subject of his blog). I wrote in, and mentioned this, and all very politely. Well, not only did Paul not reply, he deleted my post. Interesting.

Regards from Perth

Derek

This not so old topic suddenly got some spin... Besides that some people started to choose which plane to buy based on materials used for a lever cap, somebody started to make new ones from more sturdy materials:

This is bronze versions for Stanley Sweatheart lever caps:

http://forum.woodtools.ru/MGalleryItem.php?id=71912
(http://forum.woodtools.ru/index.php?topic=81364.0)

And this is lever cap for Veritas DX60 out of titanium:

https://scontent-otp1-1.cdninstagram...31937397_n.jpg
(https://www.instagram.com/p/Bp1J1LSD...=1g4sdk15pvj3c)

In case of Veritas DX60 the original lever cap stopped working after ten years in heavy use. See Instagram link above.

Is the locking screw really threaded into aluminum? If so most any machinist or mechanic would say that is a poor design. Aluminum threads are fine for assembling transmissions etc where infrequent use is expected but aluminum threads do not hold up well to much reuse. Would you make a chisel from it?