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Bigger hammer

Thoughts on the New Ends

I've been thinking about all the techniques that will be involved in making the new ends for my concertina. Several of them I have never done before, or not to the level of detail and finish I'm aiming for here. I've decided that it would be a good idea to make a partial end first to practice on, as I would hate to make an elementary mistake and ruin one of the real ends at a late stage in the process. Here's a photo of the kind of end I'm planning to make. I haven't yet decided whether to do the fretwork in the middle circle around the key holes - my concertina probably didn't have it originally (like this one).

Mainly to get my own thoughts in order and make sure I don't forget anything, here's a list of the steps that I think will be needed to make the new ends:
  1. Cut the maple boards roughly to length.
  2. Plane and sand one long edge of each board to get it perfectly flat and straight (possibly at a steep angle to increase the surface area of the glue joint)
  3. Glue the boards together edge to edge and press flat until dry.
  4. Mark the shape of each action box side onto each board very accurately (marking the boards so I know which side they are and which way up).
  5. Cut and plane/sand the boards a fraction of a mm smaller than the action box sides (to leave room for the veneer).
  6. Make a scratch stock from photos of the edge moulding and use it to mould the edges of the boards.
  7. Sand the faces of the boards to get them very flat and smooth enough to veneer onto.
  8. Veneer the moulded parts of the boards using six strips per board, carefully bevelling the ends to avoid gaps in the corners.
  9. Trim off the excess veneer.
  10. Veneer the main part of the top of the boards and the whole of the bottom and press flat until dry (you do the bottom at the same time to reduce the risk of warping as the top veneer dries and shrinks).
  11. Trim off the excess veneer. The aim at this point should be for the bottom edge of the board to be a tiny amount bigger than the action box sides, so the joint can be blended together later.
  12. Lightly sand the veneer to get it smooth and blend the joints where necessary.
  13. Inlay the metal corner decorations (a very kind member of the concertina forum is sending me an original set of them).
  14. If necessary, fill any small gaps between veneers and around the inlays with a filler made from a mixture of glue and sanding dust.
  15. Prepare the fretwork template and glue it on (probably using thin hot hide glue).
  16. Drill at least one hole in each piercing for the saw blade.
  17. Cut all the fretwork with an electric scroll saw.
  18. Drill the mounting holes for the thumb straps and little finger rests (clearance holes for the long screws and pilot holes for the short screws).
  19. Accurately mark out and drill the key holes (need to figure out a good way to locate them).
  20. Ream the key holes slightly oversize with a shallow taper reamer to make space for the felt bushes.
  21. Remove the paper fretwork templates.
  22. Clean up the edges of the fretwork where necessary with needle files and fine emery paper.
  23. Remove the old lacquer from the action box sides.
  24. Make the tops of the action boxes flat (this will probably involve gluing strips of veneer on to build up the low areas and then sanding down the high areas using sheets of emery paper glued to a flat worktop).
  25. Glue the action box sides onto the new boards, lining the edges up very carefully.
  26. Blend together the joins between the boards and the sides with fine emery paper.
  27. Drill the bolt holes through from the bottom.
  28. Possibly stain the top veneer and the inner edges of the fretwork to get it to more closely match the colour of the original veneer on the action box sides.
  29. French-polish.
  30. Produce new maker's and serial number labels and glue them on (will need to get them photocopied or laser printed onto good quality paper).
  31. Make and fit the woven wool felt key bushes.
  32. Possibly replace the support pieces inside the action boxes (I suspect the old ones won't be exactly right for the new ends).
  33. Re-assemble the instrument.
  34. Breathe!


Re: second point.

DO NOT SAND the mating surfaces. You want then clean straight and complementary to produce a flat board surface.

To do this right take your two pieces of maple and arrange then in the orientation you want them. Mark the top faces and alignment one with the other (butt the edges together and run a pencil or scribe across the join between pieces). Take a piece of tape and tape the pieces together (this is just a reminder of correct orientation until you do it automatically).

Now take one piece and turn and place it on top of the other piece treating the tape as a hinge. Now align the two edges together as closely as you can. Clamp the pieces together in a vice Now take your plane - the longer the better a Record 5 1/2 smoothing plane is possible if you're careful a Jack plane (Record No 14 I think) with a longer foot would be better.

Now plane using multiple light full length sweeps. Do Not attempt to take too much in any one pass.

The rational for planing both pieces together is that unless you are *very* practised you are not going to get a perfect 90 degree edge so you produce two edges with perfectly complementary angles to leave you with a flat board.

This can be taken from the vice to check closeness of fit but put it back in the same orientation for both pieces.
This gives you what is called a rubbed joint and can be immensely strong the better the joint the stronger the bond.

should you decide to reinforce the joint you should first produce a good rubbed joint then mark and fit your preferred reinforcement, be it dowel or loose spline.

Given your intention to veneer the ends please remember to counterveneer i.e veneer both sides of the board to equalise the stresses. By the way modern commercial veneers are normally between 0.7 and 0.8 mm thick. model making or 'construction' veneers are closer to 1.5mm thick
Thanks John, I will prepare the joint like that. I have a Stanley No. 5 Jack plane (14" long).
BTW I'll probably be asking your advice about stains and French polishing at some point...
I've just found a very rusty 22" long Record jointer plane in my dad's garage. Possibly a bit *too* long for this job!

Also found a very interesting looking plane - a Woden W78. Also very rusty but all the parts look to be there. Nice find. :-)
Sounds like two very nice finds.

I'm slightly tempted by the Woden, but as i have a Record 405 with a complete set one and most of the set two cutters I really don't need it (At some point I must see whether the blades made for the modern Clifton multiplane will fit the 405)

Suggestions for removing rust: a very little light machine oil and four zero wire wool for the non critical and only lightly rusted parts. For the rest (Plane sole, mounting frog and the like lay a piece of fine carborundum paper onto a piece of plate glass and polish the sole of the Record and foot of the Woden using a straight stroke for the woden (along a guide to keep it vertical) and in a figure eight for the Record , be sure the whole of the sole passes over the paper.

Don't be surprised to find the toe and heel of the plane becoming shiny before the middle. Cast iron will actually move and if the plane hasn't been tuned before now you can have a curved sole with a deviation measured in tens if not hundreds of thou over a twenty inch length.

Unless the bow is extreme it's best not to take the plane to an engineers to mill it flat, taking that much metal off has it's own risks and changes the internal stresses in the metal. Slow but sure is better.Oh and don't remove the frog while doing this. just wind the blade up and clear of the base.