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About lehmann

  • Birthday 07/21/1960

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    Surrey, BC, Canada
  • Interests
    USS Constitution: Scratch build solid hull 1:96 scale

    Member Nautical Research Society

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  1. There are digital dividers, such as IGaging Digital Divider/Compass Not cheap, but not exorbitant. However, before becoming obsessed with small measurements, remember that it is also not possible to manually draw small objects accurately. CAD can do better, but there is still always a line width that is typically several pixels wide. If the part is small, the dimensions should correspond, in scale, to something a person can pick up or grab by hand. So, adjust your numbers accordingly. Actually, for small parts it's the relative dimensions (proportion) that matter
  2. Spear & Jackson is still around, although they have merged with other companies, as has happened to Disston Saw. They are no longer making the larger saws used in sawmills and ship yards, but they were still applying for patents for insert teeth (Figure 79, page 64) in the 1980's. Several people I worked with did their saw-maker/saw-filer apprenticeship at S&J plant near Vancouver, Canada.
  3. Agree. Spruces all have a definite late-wood "line" with a softer early-wood between. The wood has a high strength to weight ratio, hence the use in spars and airplanes, but only if the grain is straight and the edges of the board are parallel to the grain (no grain angle or run-out). Some sawmills in my area ( British Columbia, Canada) are still occasionally cutting Sitka spruce, but mostly for Asian markets, which are willing to pay high $. Logs that meet the standards for a Japanese temple log can sell for $30,000. A wedge for making cello backs sold for $130 (20 years ago!).
  4. One boat missing from your list is the Spray - Josha Slocum. Blue Jacket models has a kit: http://www.bluejacketinc.com/kits/spray.htm
  5. Draftsight is a free, fully functional 2D drafting program from the same company that produces SolidWorks (3D cad). Basically, a similar program to AutoCad or TurboCad. I've run it on both Windows and Linux systems
  6. I recently pickup this pickling chemical from a local jewelry supplier. Pro-Craft Pickling compound (No. 45.122): Sodium Bisulfate. 10 oz bottle makes 1 quart. Solution works well at room temperature, but faster at about 125 F.
  7. Pre-bend planking: looks like a feature you should have paid more for. I would just wet the areas with the hardest bends/twists to avoid creating fuzzy grain and water stain. Maybe heat with hot iron. The longer, slower bends should straighten out as needed, although if you're planning to rip into strips, they could be awkward. What is the intended use?
  8. I have two of these sleeveless drums from Lee Valley Sleeveless sanding drums. The picture on the web page doesn't show the method for holding the sheet of sandpaper, but it works very well. There is a slot in the drum to insert the two ends of the sheet and a simple, but effective locking method. No problem getting the sheet tight around the drum. I see that they are also sold at https://woodworker.com/1x3-w-14-shaft-sander-sleeveless-drum-mssu-815-895.asp. The picture there gives some idea of the slot and design.
  9. There are a lot of features that don't make sense for this to be a regular block. The top lateral through-hole would not be able to take much load as the end-grain would easily pull out. For this to take a tension load there would have to be an iron band around the block. This is a large block, so it's not for small rope or small loads. Also, if the outer corners are relatively square, so chaffing would soon cut the rope. To me, this means a pin, wooden or metal, went through the through-hole. The tops of the pulley mortises appear to intersect with the bottom of the lat
  10. Greg, The source of almost all published properties for North American woods is from the USDA book "Wood Handbook: Wood as an Engineering Material" based on tests done at the Forest Products Lab in Madison WI, and similar facilities in Canada. Click on the link to go to a page to download the book. (It's free, paid for by US tax payers) Boxwood isn't listed in the USDA book, probably because the volumes of commercial harvest are so small and it's not used for structures. I haven't been able to find a source for the Wood Database numbers. The listed properties on the Woo
  11. This doesn't sound like the the yellow cedar I'm used to, which has a hardness similar to black walnut. It's a slow growing species, so generally has very fine grain with faint annual rings. No way I can indent it with a finger nail without really trying, especially after it has seasoned for a while. Excellent wood for holding detail in carvings. Maybe the source is a second growth stand in open sun light, which will grow quickly and has a lower density.
  12. Filling all the gaps is probably not a good idea, although tempting. On another post (Drazen), someone had filled all the spaces between frames with solid wood. The problem is that wood will move with humidity, and he ended up with cracks in the planking, especially at points where the filler piece wanted to move and the plywood bulk head didn't. The lessons from that, at least for me, were: leave a gap between the filler and the bulkhead. If not a gap, put a soft layer of cardboard that can flex and shear as the wood moves align the grain of the filler with the grain of the
  13. In doing your tests, be aware that the blade may flex when you push against it during your measurements. If you want to verify this, put a dial indicator on the back side of the blade. Also, the fence will flex a little as well as it may not always register square each time. When you're trying to work in the range of 0.001" you need to watch for these things even when using large metal working machines. I do some work at 0.0001" and have to be hyper vigilant. If you want to just test the accuracy of the IGaging system, I suggest zeroing on a block of wood clamped solidly to t
  14. The main concern here is whether the fence is parallel to the saw. If the back of the saw is closer to the fence than the front, then the saw will be pushed sideways, That's the only way I can imagine getting 0.090" thicker.
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