Just a quick update on the 439: used it a couple of week ends ago for the first time in ages. Blunt knives; swap over necessary. I was also getting a bit of snipe off the planer.
But I have a fast and pretty much foolproof method of knife changing:
- Collect together:
- Two sheets of clean, dry 80g A4 from the office,
- one of the smaller bits of toughened glass I use for Scary Sharp,
- some heavy weights (the 3/4" steel fishplate I use as an anvil, and a small toolbox full of spanners would do it)
- 10mm open-ended spanner with a narrow end
- Work gloves, to avoid "paper cuts"
- Remove everything sticking out above the planer outfeed table (fence and mounting, guard and its arm).
- Rotate the block so a blade edge is exactly TDC (my Kity has alignment marks on the bearing housings). Remove the blunt knife and replace with one from the spare set. Push well down in against the springs and temporarily tighten a couple of the bolts.
- put one sheet of A4 on outfeed table so the end comes just to the ends of the fingers of the table.
- Being careful to keep the blade TDC, put the second sheet over the first, overlapping so that it extends to just cover the blade position.
- Very gently put the glass plate on top of both sheets of paper and so that one edge of it is just over the knife, and weight it down.
- release the bolts gently so the knife comes up to touch the paper sheet. Carefully tighten everything up so it's good.
- Repeat for the other side.
When It's done, I do a sanity hopping-check with a thin strip of wood at either end of the knives. They should pull it forward by about 1/8" (3/16" absolute max.). It's more important that all four ends are the same than an absolute value, but
if the projection is too little you get snipe at the beginning of the stock (too much projection gives snipe at the end). I find the thickness of 80g paper is near perfect.
The thicknesser shouldn't cause snipe at all (or at least, I can't see how it can unless the machine is being dramatically abused somehow).
Hope that's useful to someone - the magnetic-clampy-micrometer things can't work, incidentally, for several reasons:
- the planer beds are anodised white metal castings, so not magnetic,
- they aren't removable in use to get at the cutter block
- even if you could get the magnetic thingysto fit, the fingers are slightly angled, presumably so stock doesn't jam against them if the knife height is wrong.
- When stuck on the drum, there's no built-in reference to the outfeed table, so you'll spend forever (and waste a lot of test stock), getting it all correct.
The plate-glass method ought to work for other machines too, and you might use anything rigid and flat instead of my piece of plate glass. But it guarantees the knives are parallel to the outfeed table and the right height, so all you need to do then is check the fence is square to that, and you're good to go. It takes about ten mins to change to a sharp set of knives (longer to find everything than actually do the task). You do need quite a lot of weight against the springs, but it's over the outfeed table's mounting bolts so won't cause it to bend or sag.