Brass mouth insert question

[Matthew N. Masail]

I am working on a couple smoothers in Wenge and decided that a brass wear-strip is a good idea.

I have some brass screw and could do it ala Derek Cohen, but I also have some strong system3 slow cure epoxy's at work that I can use. do you think the brass screw are necessary or would the epoxy be enough? of course I am thinking long term here, even 25 years down the road I wouldn't want the insert to pop off.

The main advantage for me for using only epoxy is that I can make the insert only about 1\4 inch wide, where if I use screws 3\4 inch wide would be the minimum starting point.

[Malcolm Schweizer]

Good day Matthew,

First off, I would love to see pics of the smothers when done. Wenge is beautiful wood. As for epoxy only for the wear strips, I would advise against it. Epoxy softens with heat, and the plane generates friction heat during use. Also, although epoxy will stick to metals, it is not the greatest bond. That said, what you could do is dovetail the brass wear strip and then epoxy it and be fine.

[bridger berdel]

I think that the longevity of a brass to wood glue joint is up to a bunch of factors. If your wood is well cured and stable, if the glue area is not too large or too small, if the glued surfaces are prepped well (clean, not too smooth, very good fit) and there won't be a lot of stress on the part it will probably be OK. I don't know how wenge is to glue with epoxy. Some tropicals are problematic.

That said, I think that all of my brass and wood old tools have pins holding the brass on.

[Matthew N. Masail]

Thanks guys, I guess brass screws or pins it is. I could slightly chamfer a hole in the plate then glue a brass dowel into the wood and peen the top. I did consider dovetailing however it would be much harder to do.

Malcom, I'd be happy to share the pics, I also have some in the work out of Israeli white ecaliptus (not figured) possibly with olive wood wedges (highly figured). all of these I am taking my time to make them to a higher standard than I ever have before.

[ian maybury]

Another here cautious about the longevity of a glue bond in that situation Matthew. There'd be quite a bit of stress cycling going on what with moisture content changes and temperature, so it might be asking a lot of it over time.

My experience in the adhesives industry suggests that even joints that are nominally perfectly OK can run into problems. If only because of minor process variations - contaminant levels has built up in the solvent used to wash the parts for example, or there was some minor change in the parts manufacturing process that resulted in a minor but critical difference in e.g. surface finish. Then there's the question of whether the joint can deliver real longevity, because testing is always some accelerated facsimile of reality.

This is just floating thoughts (and no doubt there's recognised ways of installing brass inserts), but depending on the situation it might make sense to bed the brass part in epoxy, and use screws as well. Maybe having pre-drilled the brass tap through the epoxy afterwards. Or even coat the brass with a PVA release agent, and bed it in epoxy - it'll pop free fairly easily afterwards, but the result will be a very closely fitted seat. Then drill and if necessary tap for the screws.

One need in the latter would be to prevent filling the epoxy with bubbles, it'd also need some sort of smart dam arrangement to contain the epoxy and stop it flowing where you don't want it. Situation permitting it's generally do-able with a liquid epoxy by taking care when pouring and stirring to not overdo it and trap air, but the thicker pastes like Araldite in a tube will cause problems. Against that very accurate ratios and thorough mixing are important with epoxies, so don't rush it. The people that pot/encapsulate ornaments probably have ways of dealing with many of these issues...

[Steve Voigt]

You might want to look at (Krenov planemaker) David Barron's blog. I recall seeing a post about dovetailing in inserts.
Rather than peen a brass a brass pin, I would use brass screws, but make the countersinks on the insert undersized, so that the screws sit proud. Then file them off flush. Just make sure that however deep the screw slot is, the screws sit proud a little more than that, so that the slots completely disappear when you file the heads off.

[ian maybury]

This is possibly the piece you mention Steve: http://davidbarronfurniture.blogspot...ed-planes.html

It jogged my mind that there was a piece by David in a magazine in my collection in the small room covering the build of a Krenov style smoother - with no insert. It's issue 161 of the UK Furniture and Cabinet Making, Christmas 2009. It's likely they have back issues available if of interest. Or i could scan and e-mail it.

What's interesting is that he makes no mention of how he planned to secure the insert - maybe he did reach for the epoxy as the sloped inner surface would mean screws would have to be very carefully placed and quite short. There's not a whole lot of detail on the detail layout of the mouth area actually in either piece.

[Derek Cohen]

Hi Matthew

The reason I have used brass to finish the mouth of some planes is because the wood used is brittle and vulnerable to chipping in this area.

The brass is screwed down but it is first locked down with epoxy. The epoxy is to hold it in position when drilled for the screws. The screw holes are very slightly chamfered to seat the head below the surface. When the head is file away, any gaps are then minimised, generally invisible. However the epoxy is important to prevent any movement when completing this work. I would not like to rely on epoxy alone to remain stable later.

Regards from Perth

Derek

[Zander Kale]

Here is a brass insert I added to a transitional two years ago, it has gotten a fair bit of use lately, no problems even though the wood has expanded such that the body is wider than the insert (the body was saturated with BLO). The bottom of the plane is coated with epoxy and that has worked out very well.
In addition, I have several HNT Gordon planes with brass inserts (that look very much like the one David Barron used, as mentioned above), don't know how they are attached but no problems after ten years.

[Jim Matthews]

I have an HNT jack that gets the occasional workout. January was very dry and the mouth was measurably wider, as the wear strip is attached only at the front. I would suppose a dovetailed insert as DC shows would be preferable.

[ian maybury]

There's something beautiful about the combination of brass and wood.

It's pretty implicit in Derek's, but it seems clear that screws alone might be a little risky too. The epoxy and a good fit would ensure that the brass is well supported, and that the screws don't get worked more than is necessary. Again implicit, but it sounds like careful choice of screw, use of a reliable drill press and some trials might pay dividends too......

[Matthew N. Masail]

I must say I'm a little confuse. there are 2 issues:

1. how to install so it wont fall out.

2. avoid issues with wood movement which isn't mentioned much.

for issue no. 1 I'm quite confused because a dovetailed insert as posted on David Barron's blog (thanks for the link Ian and Steve) would be easy enough to do, but how does that help it to not fall out? the dovetail only helps against forward movement, which is something, but far from all. it does look nice though.

for Issue no. 2, on a laminated plane, isn't anyone worried about the insert pushing the sides apart if the wood body shrinks? Derek I have wondered this since I saw your Jack plane build, am I worried for nothing?

Zander, That seems very functional in all aspects, but it's not quite the look I'm going for, I'd rather have to insert not show on the sides. looks like you removed the mechanical adjusters and added a thick iron also? that must be a nice plane to use.

P.S, its needless to say that as Derek mentioned the reason for the insert is because I'm not sure the Wenge will hold a non chipped mouth for very long. but there is another reason, I find my wooden planes wear much more in front of the mouth than anywhere else, this is not new of course, and when it happens it effects the uniformity of the shavings and makes the plane harder to set. I think a brass insert should solve both these issues and prolong the time between sole tune-up (lightly done with sandpaper on a flat surface).

[Zander Kale]

Zander, That seems very functional in all aspects, but it's not quite the look I'm going for, I'd rather have to insert not show on the sides. looks like you removed the mechanical adjusters and added a thick iron also? that must be a nice plane to use.

I'm happy with how it works. It is pretty much an single iron (3/16") infill bedded on 3/8" aluminum.
You could use wood instead of brass and put the grain vertical (ala boxing). Some Japanese planes do this (dovetail across the sole in front of the blade with vertical grain key).

[ian maybury]

Must say Zander that there's something about the chunky look of that plane that really appeals - down to the lightly exaggerated flare on the top of the handle.

The layout should sidestep the concern about width wise wood movement too. Another option might be to allow a shade of clearance at both ends of the brass insert - not ideal, but it might not need very much. Zander's comment in his first post about the body expanding relative to it might suggest that a little movement is possible.

Are materials other than brass used for inserts?

[David M Anderson]

Zander, that plane is beautiful.