recessing the sole of a plane

I debated whether to put this in the woodworking or fabrication section, but I figured all of the plane experts are over here.

I have some welded plastic assemblies. The weld in question here is an ~82" long single bevel weld. After welding, some of the weld material sits proud of the surface. I shave this down with a wood plane. I really just need to plane down the weld bead (~1/4" wide) and don't need to plane down the parent material. What I'm thinking is to take a plane and mill a 0.5" wide by a few thou deep. If I then set the blade flush to a thou above the sole, I can quickly plane down the weld without biting into the parent material.

My questions are:

1) Is this a stupid idea? You never see it done and I have no clue if the blade arrangement would cause problems.

2) Any thoughts on fixturing the plane? I was probably going to clamp it in a vise, indicate it to make sure it's flat, and go for it.

It's the kind of thing i'd do if there was a need here.
You can still get #4 & #5 size bench planes, and many decent adjustable toe (or not) block planes at flea markets and garage sales for under $20. Often under $10 even for what was originally good quality models.

The (potential) fly in the ointment is whether the depth you mill combined with the shaving thickness desired, comes out to be the height of the weld you want when finished. If "all" welds are one pass clean-up, then there isn't even anything you have to calculate.

(Hand pushed) routers with a clearance front would work right out of the box at (usually) a somewhat higher price.
Be sure to get the adjustable depth shoe with it. Then you can set the device to take a comfortable shaving, and work down until the whole sole contacts, sole of router being your final depth stop. Router blades are somewhat less convenient to sharpen than plane irons, though.

There are also drop-nose shoulder planes, where you could set the blade to the rear sole for final depth, and set the nose to the blade for shaving thickness.

Perhaps the easiest/most stable might be a lever-depth adjusted block plane. mill the channel as you described. Use the lever to rapidly change depth for succeeding shavings. Perhaps add a stop to the lever throw. Or just eyeball it. Again all moot if the welds are always one-pass.

On commercial jobs, like for trimming floor plugs, i just make a straddle-base for a tailed router for the crews. But for plastice the hand plane would give a nicer finish without burrs.

Please show pics when you solve it!


smt

Sounds like a good idea to me. You could test it out by putting some tape on the sole of the plane to create the channel. Something like UHMW tape w/ PSA would probably work great.

richard newman said:

Sounds like a good idea to me. You could test it out by putting some tape on the sole of the plane to create the channel. Something like UHMW tape w/ PSA would probably work great.

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Realyy!

No need to cut the plane sole. ADD material.

But really, plastic is so elastic, that if the plane is set correctly, only the high material will be cut. Open the throat if you need to.

Somewhere I have a set of instructions on making a tool for this sort of thing. It's a metal puck with a couple of inches of vixen file let in to be just a few tenths below the surface, so you can file rivets and pins flush to a flat surface. Can't remember what it's called.

Dynabrade makes "training wheels" for the end of their hand held belt sander to a very similar operation.

Use a trim router. Make a sole plate with a groove for the weld.

Loose the hand plane idea and buy a cheap laminate trimmer. 1/2" cutter with .25 shank. Make 2 skis for the bottom so it straddles the bead. Adjust as needed. Common solution that works in one pass.

Scruffy887 said:

Lose the hand plane idea and buy a cheap laminate trimmer.

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Noisy tho. A hand plane is so relaxing.

Almost forgot. The relationship of the blade, sole, cap of a plane is very important. It is supposed to glide over the surface removing a very thin set amount. Do not cut a groove if wanting a hand solution. Add 2 spacers to the sole to do a better thing, it will still work as intended. But stop cutting when at set depth. Ski router is still a whole lot easier and faster.

As mentioned in my original post - the powered router solution does not work as well on most plastics as a hand plane.
Leaves a swirl, mars the plastic if not dead flat, or leaves high spots. On some plastics it leaves fuzz which is time consuming to get rid of.

I actually use a block plane on some plastics, but not for welds. For edges, bevels, and for flushing up.

Gonna have to remember the 2 pcs of tape method as mentioned by others.

smt

This is one way I I modified a metal woodworking plane. The method was from Fine Woodworking or similar magazine.

Turn the plane upside down and what does the sole look like? It has a leading edge, a slot for a blade, and a trailing edge.
The modification is to remove metal from about 3/8" from the start of the sole until 3/8 before the slot for the blade.
Remove metal 3/8? from the rear of the slot to a edge 3/8" from the end of the sole. The 3/8" figure is just a rough guess
and the depth of the recess is no more than 1/16". The plane worked but from my memory now I think a friend liked it more
than I did and I gave it to him or he offered to buy it.

HP-8 Mini Block Plane – Bridge City Tool Works
You set the sides maintain height off parent material.

memphisjed said:

HP-8 Mini Block Plane – Bridge City Tool Works
You set the sides maintain height off parent material.

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Boy, that is a nice little tool!

If this is a one-time deal I'd bond shims to the plane sole using something that can be popped off later with a heat gun.

If it's long-term use I'd still use the shims but with a permanent adhesive.

Simplicate, don't complicate. That special block plane is nice but being more complicated there's more chance that a setting might change if bumped.

I made this to cut 45 degree angles on the edges of cabinets, etc.
Also made a wide body for a regular block plane.
Another one could be built for flat surface removal.

Lie-Nielsen used to offer an adjustable mouth block plane with a milled slot recess for fishing pole makers. Bamboo maybe? It’s been years since I’ve seen the option. Seems like any option offered here on the plane mods would be doable.
Joe

Joe Rogers said:

Lie-Nielsen used to offer an adjustable mouth block plane with a milled slot recess for fishing pole makers. Bamboo maybe? It’s been years since I’ve seen the option. Seems like any option offered here on the plane mods would be doable.
Joe

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That tool would displace all those Indian pole makers working on the ground with their bare feet ...

rons said:

I made this to cut 45 degree angles on the edges of cabinets, etc.
Also made a wide body for a regular block plane.
Another one could be built for flat surface removal.

View attachment 327665

View attachment 327666

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It came out of Fine Woodworking or Shop Smith....

I don't think your idea will work too well. It seems like it should however if the plane sole is not resting on the weld bead then it has to cut the weld bead in one pass.
If the hand plane is capable of cutting the weld bead in one pass then it may work for you.
Can you post a pic of the part you need to plane with some rough dimensions?

I have never cut plastic with a hand plane but have lots of experience hand planing.

I think a better solution would be to just grind part of the blade away so that you had only half a cutting edge and you could even add a fence to the bottom side of the plane so the blade would just barely extend past the weld bead. These two modifications would allow you to cut very quickly and accurately with no risk of cutting into the parent material.

This is the same concept as my power lipping planer that has an adjustable fence and works kind of like a mini jointer to flush trim solid edgings on panels up to 1.25" wide. I was going to suggest this tool but others have said that flush trim bits don't work so well on plastic. Look up lipping planers so you can see how they work if you are interested.

Memphisjd,
That is an incredibly nice tool and at that price I might order two!
However I don't think it will work for this job as it is meant to cut to a specific height not flush trim when using the side height plates.