What is an acceptable gap when using a hand plane?

[tibi]

I find that the only way I can get a cap iron to contact the iron without any gaps,
is focusing on the center of the cap iron when honing the underside...
i.e using something like a stuck down short abrasive strip not as wide as the cap iron is, or the corner of a hone.
Otherwise I end up with a gap at an end.



50 degrees on the top side is what most folks using the cap iron suggests,
David W has wrote quite a lot about the cap iron, in articles like wood central, and here, and has made quite a bit of youtube content about using the double iron plane, which if you need use the cap iron is one of the only sources that is thorough on the matter.

Not that it's complicated or anything, but its hard for some to let go of some of their fundamental beliefs which they have followed since the beginning.
i.e having tight mouths mostly, but also steep bevels,different frogs, back bevels and so on
See the shavings and choose for yourself and decide.

That's what your looking for if your wanting more information on smoothing,
but you need a bench first and I suggest having a go at finding a top for your sawhorse(s)
A pair of stiff beams jointed and affixed or even clamped to a solid core or fire door to prevent droop, would be an instant bench if you made up some of these plywood risers

Butt it against the wall or similar thing which might be against the wall
View attachment 97339
Alternatively maybe this video might be of interest


All the best

Thank you very much. I will try to grind the underside of the cap iron (I have the classic Stanley type) on an edge of a water stone to get only the center down.

I needed to move out of the garden shed out to the garden, as we do not have enough space and store many things in the shed, so I have built two sawhorses and a 50 mm top. I made them removable, so that I can pack everything and store it in the shed during the winter. I have connected everything with screws or bolts. But when I started to plane, the whole bench was tilting towards the planing direction and back when the force was released. It was no fun, and results were pretty bad as well. So I have decided to keep the top and build a proper, bench with 100x100 mm legs and mortise and tenon joins next spring. I have calculated that total weight will be 60 kg. I need to make this bench smaller (150 cm x 60 cm) and I will move this bench back to the shed, so it will be inside. I want to create a low shelf a few cm above the ground and I will store there my thickness planer and compressor (of course I will cover them, so they will not be full of shavings), and that will add another 50 kg of weight.

I am attaching the photo of the original top on the sawhorses, that did not work for me.

 

[jcassidy]

I am attaching the photo of the original top on the sawhorses, that did not work for me.

Your bench has no lateral strength, which is causing your problem. In the meantime, you could strengthen the bench by bracing both ends of your current bench by using beams from the frame/bench to the ground at at angle, no more acute than 45°. Stake the ends into the ground and notch the other ends to fit your bench.
If you have back/forward movement, not just side-to-side, you can use brace on each corner, like a tent. This should alleviate your problem until you organise space for a proper weighty and solid bench.

 

[paulrbarnard]

I am attaching the photo of the original top on the sawhorses, that did not work for me.

I’m not sure if it is practical but attaching a bracket to the wall for your bench to rest against in the direction of planing might be a short term simple fix.

 

[tibi]

I’m not sure if it is practical but attaching a bracket to the wall for your bench to rest against in the direction of planing might be a short term simple fix.

Thank you very much for your answer. I did not want to use brackets, because they would interfere with the area, where I could use clamps. Anyway, I will not work during the winter in the garden, and I will build the workbench as the first thing in the spring.

 

[tibi]

Your bench has no lateral strength, which is causing your problem. In the meantime, you could strengthen the bench by bracing both ends of your current bench by using beams from the frame/bench to the ground at at angle, no more acute than 45°. Stake the ends into the ground and notch the other ends to fit your bench.
If you have back/forward movement, not just side-to-side, you can use brace on each corner, like a tent. This should alleviate your problem until you organise space for a proper weighty and solid bench.

There is this Lie Nielsen Workbench

It has a very similar type of construction than my sawhorse workbench. What makes it laterally stronger than mine? Is it the thicker top or joints or thicker legs or hardwood material? Lie Nielsen workbench has thicker top, but the underlying construction is similar to mine. But has thicker wood. I need to know that, so that I can avoid the same mistake when building my bench in the spring.

Thank you

 

[paulrbarnard]

There is this Lie Nielsen Workbench View attachment 97343

It has a very similar type of construction than my sawhorse workbench. What makes it laterally stronger than mine? Is it the thicker top or joints or thicker legs or hardwood material? Lie Nielsen workbench has thicker top, but the underlying construction is similar to mine. But has thicker wood. I need to know that, so that I can avoid the same mistake when building my bench in the spring.

Thank you

The frame on this is hardwood and the legs are around 100mm square. That will help. However the biggest difference is where you have put the stretchers. By fixing them to the tressel cross member you are adding a lot of additional flexing possibility. Simply moving the stretchers to the legs as in the LN example would help some.
I'm not a fan of the knockdown fasterners for something requiring great rigidity. My bench has a similar construction but connections are all with wedged through tenons.

 

[MorrisWoodman12]

I seem to remember seeing somewhere that PVA glue is good for joints with gaps up to 0.3mm but darned if I can remember where so 0.1mm or less is great.

A trick when edge jointing boards is to plane them both at the same time. That way they will both have the same 'incorrect' angle. When you put the boards together the two incorrect angles cancel out exactly. On the length of the joint it is better to have a very slight dish rather than crown, that is much less likely to show a gap.

Also if you plane both boards at the same time your plane is on a wider surface so less able to rock/lean as you plane.
Martin

 

[TRITON]

Gluing up the cramps will pull it in tight, but one important thing to remember is DONT wipe off the glue.
When you cramp it up and glue squeezes out.
If you do what happens is the surface tension draws the glue back into the joint and away from the surface.

 

[D_W]

One of the best glues for invisible glue lines is PVA. I know craftsmen and women who insist on using PVA, even when it's far from the best technical choice, simply to achieve the best glue lines. Unfortunately it isn't always possible, a classic example is with lamination work, UF glues are the better choice technically, and sometimes you just have to accept sub standard glue lines in order to benefit from their lack of creep and spring back. Here's a crest rail on a chair that I made, it would be nice if the laminations were invisible, but with the UF glue I used that's never going to be achievable

View attachment 97330

Custard, that joint between the lamination and the chair sticking is just a thing of pure delight. It appears as if the laminations grew directly out of the wood.

(I use white glue on guitar bodies for the same reasons you say - I don't want the joints to show, especially on well matched mahogany or limba where there's enough action on the surface of the wood to completely hide glue joints).

Putting hide glue on electric guitars is all the rage right now between body parts and tops, but i doubt it matters even there unless the glue joint is fat enough for the glue to be soft (that's to be avoided!).

 

[jcassidy]

Your side-to-side movement is caused because you haven't locked down the frame with sheer weight, heavy thick beams, tight joints, and glue. This is the essential difference between the Nielson workbench and yours. Which is understandable as you want a bench you can move and take apart.

For these reasons, you need to brace your bench against an immobile reference, whilst retaining the 'take apart and carry away' option. I note you say you don't want to brace against the wall, so bracing against the ground remains an option for the interim. Or remake your bench with thicker wood.

You can also consider internal bracing from the horizontal to vertical beams using simple 45 degree braces, but your bench appears quite lightweight so I'm not sure the entire bench won't move back-and-forth.

Hope this helps!

 

[Awac]

Hello,

I would like to ask if there is an acceptable gap between the straight edge and the wood when checking along the width of the board when hand planing the face or edge when hand joining the edges for glueing. I have seen many videos on the subject where instructors tell that no light should be visible, but I cannot achieve that across the full width of the board or full width of an edge. When instructors check for the light under their square or straight edge, there is not enough resolution to see if there is actually no light, or the gap is tiny and they consider it to be OK.

For faces of the board, I can get 0,05 mm - 0,1 hollows across the width of a board (e.g. 150 mm) and for edges, I can get similar results, but the line seems to be wavy for me. If the width of the edge is 30 mm, there are one or two places with miniature gaps (below 0,05 mm), but I steel can see light through them.

There is either a bump in the middle across the width, or one side is higher than the other. I have never encountered a situation where the middle of the edge would be hollow.

When I move the square along the length of the board to check the light, the contact point starts usually at one end of the board, then goes to the middle of the edge and then goes either way to one or another edge of the board.

I have almost never found a section, in which I have seen no light under the straight edge, although the gaps were below 0,1 and sometimes below 0,05 mm.

I check the gap with feeler gauges, that can measure up to 0,02 mm (that is 0,8 thousandth of an inch)

This is valid for planing oak, when planing fir, I can get sections where I cannot see any light under the straight edge or square. It may be caused by the softer structure of the wood and that it can be pressed a little to close any gaps.

I would like to ask if my results are good enough and I should put up with it or I should improve my sharpening, plane setup or planing technique to get really no light visible under the straight edge across the whole length of the edge or across the whole width of the board. If I check the length of the boards, I can get a tiny hollow in the middle as well, but I know that this is acceptable if it is not too big and it is not a bump.

The gap may cause me the biggest problem when glueing the legs of a table from multiple boards. I need to glue wider boards together face to face. And having a wavy surface on both sides, although miniature, can have a negative compound effect.

Thank you.

I was thinking about your question and thought where have I seen something that might help you. This was an article in Fine Woodworking. You can also make a fence to go underneath you handplane and use a tiny clamp to hold it in place to get a 90 degree.

Jointing with sandpaper
I designed the jig shown above for jointing edges when I was using
thin, salvaged timber to be glued up into wide panels for cabinet
doors. To get nearly perfect joints, I needed square, straight
edges on the thin workpieces, and my cast-iron jack plane is too
heavy and clumsy for such delicate work. The jointing jig I came
up with is a bit slower than a plane, but the finished edges are
square and smooth.
My experiments with this technique have produced two models.
One model, shown in the sketch, is handheld and moved against
the clamped workpiece like a plane. The other, which is very similar,
mounts upside down in a bench vise, and the workpiece is
moved against it. I use sheet sandpaper in the handheld model and
a strip of abrasive sanding cloth (like the kind used in belt sanders)
in the bench model. In both, as the sanding grit wears down, I
loosen the screws and move the abrasive paper or cloth to place
fresh grit in the sanding area.
—Anthony Clarke, Moonta Mines, Australia

 

[tibi]

I was thinking about your question and thought where have I seen something that might help you. This was an article in Fine Woodworking. You can also make a fence to go underneath you handplane and use a tiny clamp to hold it in place to get a 90 degree.

View attachment 97381
Jointing with sandpaper
I designed the jig shown above for jointing edges when I was using
thin, salvaged timber to be glued up into wide panels for cabinet
doors. To get nearly perfect joints, I needed square, straight
edges on the thin workpieces, and my cast-iron jack plane is too
heavy and clumsy for such delicate work. The jointing jig I came
up with is a bit slower than a plane, but the finished edges are
square and smooth.
My experiments with this technique have produced two models.
One model, shown in the sketch, is handheld and moved against
the clamped workpiece like a plane. The other, which is very similar,
mounts upside down in a bench vise, and the workpiece is
moved against it. I use sheet sandpaper in the handheld model and
a strip of abrasive sanding cloth (like the kind used in belt sanders)
in the bench model. In both, as the sanding grit wears down, I
loosen the screws and move the abrasive paper or cloth to place
fresh grit in the sanding area.
—Anthony Clarke, Moonta Mines, Australia

Thank you very much for this jig, I will give it a try when having slight irregularities on my edge

 

[Nigel Burden]

Custards excellent thread on how to edge joint a board is well worth a read.

How To Edge Joint | UKworkshop.co.uk

Nigel.

 

[Dangermouse 2nd]

NOTHING is ever flat !!