« Knife set - hangi-toh handles ... | Front Page | About that newspaper ad ... »

Knife set - more testing of box designs

Posted by Dave Bull at 2:16 AM, February 27, 2012 [Permalink]

Time to get moving on the design/production of the paulownia boxes. I am very quickly running out of time for this, as I have to get started on my real work, getting some prints made!

Sato-san and I have been talking to different suppliers of paulownia wood, trying to find a good source, and the first couple of sample pieces arrived the other day.

They don't look good actually. One of them is white and clean, but has clearly been bleached (or some such treatment), and has a terrible texture and feel. The other one has been poorly jointed and would make very unattractive cases. So scratching this supplier off the list was an easy decision, but anyway, this wood will serve another purpose, for helping me get the tooling and jigs ready for the project.

And that means wrestling with these junk tools ... They are worse than I expected - far worse.

The sander is already broken; I was using it (properly) when a piece of the plastic housing came a bit loose. I shrugged and ignored it for the moment, and that was a mistake because a minute later the vibration shook it free, and it dropped down onto the belt and exploded in a shower of plastic fragments. Looking on the bright side, I can now clearly see the pulley and drive belt, so will have advance warning when that starts to fail ...

The band saw turned out to have an off-center guide wheel (which is of course non-adjustable), so the blade wavers from side to side each time that wheel makes a revolution. I have brought the blade guides in as close as possible, but the blade then rubs alternately against them, left right left right ...

The table saw has a couple of major problems. First is that the motor is mounted in a permanent and non-adjustable way under the table, but is not 'quite' aligned with the table - it's at a slight angle to the guide slots. And the error is the 'wrong' way - wood coming out the back of the cut is pinched between the blade and the fence, resulting in burn marks on all the finished pieces.

Second is that when I removed the blade, measured it for dimensions, and then went to the hardware store for some more (of a different type) I learned that the 15.9 mm arbor (this is supposed to be 5/8" I guess) is unknown in Japan, and there are no blades available here, period. Japanese saws are all on a 20mm arbor. The guy in the hardware store obviously knew where I had purchased the saw (it seems he gets this all the time), and just shrugged. Thanks for the 'heads up' on this before I purchased, Amazon!

The drill press is fine. I mean, what can you do to screw up a drill press?

So I really am not sure how to take it from here. To get pro tools - even used ones - is simply not possible right now. All I can do is struggle with these to get my projects moving, and then try and replace them one by one with better ones. We'll keep a look-out on the auctions, and at some point, we should find what we need ...

In the meantime, let's press on and see if we can actually make any of this work ...

I'm going to need some fairly small parts, and this table saw has a huge space on either side of the blade.

There is obviously no way that I can buy a different throat plate for this saw. I'm going to have to make one myself ...

And a few 'wasted' hours later, we now have a zero clearance (almost) plate, and a table on which we can cut small parts:

Next up is a method for ripping the paulownia planks into the correct dimension, and then for rabbeting them to fit together. The built-in fence is useless, because of the mis-aligned motor, so I've built my own:


The riser section has a couple of nuts embedded, and on this I have mounted a nice fat feather board made from 1" ply (don't complain about the 'wavery' slots, cut quickly on the band saw ...)

It has a horizontal mate that clamps down on the table.

With these in place, we should be able to rip stock accurately, and cut even the smallest rabbets. I of course tested it out right away on a piece of the bleached paulownia. For ripping wider pieces, the featherboard can't push against the saw directly, as the wood would be squeezed there after the cut is 'released'.

The feathers work best for 'internal' cuts on the wood - making the rabbet. She goes in easily:

... passes through smoothly:

... and I can either push it through with a stick, or draw it out carefully from the back end.

Rabbets! Rabbets! Year of the rabbet!

I have of course heard about feather boards before, but never actually got around to making any until now. But now that I have felt the way that this wood slides so smoothly and accurately through this saw, I'm never going back to working without them! Sometimes we get 'so smart so late' ...




Added by: Tom Kristensen on February 27, 2012 9:57 PM

Thanks for this Dave. As it happens I am in need of tooling-up with a table saw to make a lot of rabbets (never seen that word written before) and the featherboard concept is an eye-opener - rather than closing the eyes and hoping for the best, which is what I normally do. I am building some deep frames that will also act as light boxes with inbuilt LED lighting, should get that raking light effect on the print surface. My main problem is where to store another large piece of machinery.

Added by: Dave on February 27, 2012 10:05 PM

inbuilt lighting ...

This sounds interesting. I'll be interested to see how you solve the problem that arises when the light source is very close to the object - the large difference in the illumination level between the zone right next to the light, and the other side of the print away from it.

This is a real problem when photographing prints; perhaps it will be less so for 'human' viewing, as the eye is more forgiving than the lens ...

Added by: Marc Kahn on February 28, 2012 1:03 AM

Nice feathered guides!

You can solve the saw blade arbor size problem with a 5/8" X 20mm saw blade reducing bushing, available in multiple places online, for example here. When ordering, make sure that the thickness of the bushing doesn't exceed the thickness of your saw blade.

Added by: Tom Kristensen on February 28, 2012 6:19 AM

The inbuilt lighting is going to be used to create some zany effects rather than being the primary light on the print. I am aiming to cast shadows on the print and I may even use coloured LEDS in places. So, even illumination is not one of my goals here, but I think you could work towards it with a large enclosure.


Add Your Input


Remember Me? (with a cookie ...)

(you may use HTML tags for style)