J. Conrad
Member
Registered: 04/11/06
Posts: 98
Loc: Colorado
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Joe, thanks for the input, see my responses
joemcglynn said:
It looks like you're not accounting for shrinkage from the casting. I think for brass alloys it's about 3/16" per foot. As long as there is enough clearance for the blade width it's probably not critical.
Looking up this alloy, it is actually closer to 1/4" per foot shrinkage (98% the size). I am not terribly worried about clearance inside, but am keeping it in mind. We lose a little less than 0.050" across the width of the mouth, but there is clearance between the sidewalls.
joemcglynn said:
The other question is about draft on the sidewalls. I'm assuming the parting line will be at the sole. Are you going to add draft to the pattern? How will folks get rid of the taper when finishing the planes? I guess the infil can be shaped to fit the taper on the inside, and the outside can be ground or filed straight.
Yes, I'm giving it draft. The sidewalls are tapered in section. Photos are below. The inside of the casting will have ever the slightest draft, shy of 1/32". Same with the outside, but this material is removed from the outside with not too much effort to true the sides to the sole. The stuffing inside will have to be tapered to fit the casting, but again, it is nothing an intermediate woodworker can't handle. The parting line is the sole.
joemcglynn said:
Are you going to cast the mouth open? I'd be inclined to have that closed, but with the bedding angle cast in. Or perhaps no bedding angle in case folks want to make a plane with a higher pitch? My thinking is that the metal will flow better in that area, there will be less chance of sand inclusions around the throat, and folks will be able to size the mouth to work perfectly with the blade thickness and bed angle.
This is a very good point. I have been thinking for some time how I can cast the mouth open without causing issues during the pour. I'm not concerned about fracturing and whatnot, as some ave mentioned, but relying on the molten material to flow through the thin sidewalls and around the void of the mouth is a challenge. Answer? THANKS LIGHTWOOD! The photos of the No. 4 are enlightening! I will add a sacrificial boss to the bottom, which is later removed when the sole is trued. I will remove the boss, so don't worry folks! This boss allows the mouth to still be cut into the body, and once the boss is removed, voila, the open mouth is exposed!
joemcglynn said:
On materials -- Silicon Bronze casts really well, and is very weldable. If you use that for the material it's easy to repair castings that have the inevitable sand pit or whatever.
I also agree here, but magnanese bronze is much stronger (a plus for such thin castings) and inclusions will hopefully not be a problem.
Joe
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James Uhrich
Sturnella Toolworks
info@sturnella.com
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Joel (Tools for Working Wood)
Member
Registered: 01/11/05
Posts: 1100
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As for the casting having an open mouth - I just want to point out that the original article has an open mouth and the author didn't consider pouring an open mouth (in cast iron) worthy of mention. This is not to say having a removeable boss isn't a good idea - but it wasn't a big deal apparently then.
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Joel
Tools for working Wood
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J. Conrad
Member
Registered: 04/11/06
Posts: 98
Loc: Colorado
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Time for an update, here we go.
The scrap element to establish the bed angle and reinforce the sole just behind the mouth is trimmed to the perimeter. That's enough for work on the mouth right now. It's time for some walls...
Using the profile of the sole as the template, I simply trace the contour onto the edge of some stock. Two parallel arcs drawn in this way give me the thickness of the side. I'm shooting for about 3/16" thick sides in the rough.
I have purposely drawn walls on two pieces of stock just in case I screw up with the bandsaw. Hopefully, I can ge the two walls out of one chunk of wood.
Aaannnnd, success. The thin ends of one of the walls are not a concern because everything is oversized.
Using my trusty Stanley 53, I clean up the outside a little. I also use the scraps from roughing these out for support of the newly curved wall.
A little scraping afterward gets me closer to true.
Once scraped, I use a little 180gr stickyback sandpaper on a flat block to true the outside. I tried to get a photo of the witness marks left by this to no avail. It's very similar to lapping. Bumps and hollows show their ugly faces durned quick. Of note, the outside is checked against my full-size sole drawing often to ensure I'm not drifting too far from ideal.
Can you see the gauge line? I use the outside as a guide surface to establish the thickness. The bottom of the wall is to be a little more than 5/32" thick. The top, about 1/8". Of course, it's important that I made these sidewall pieces the right height before gauging the top and bottom thicknesses.
This shot kind of shows you what the inside looks like after repeating the steps I did on the outside for the inside, but now have used the little crescent scrap from roughing-out with some sandpaper to lap the inside. The fuzzy spots are high spots that I eventually work down to a uniform arced plane.
This fits good enough for now. The wall is uniform in its faces, but tapered bottom to top. I try to keep everything oversize just a little bit until the total fit-up of the walls so I can trim the corners perfect.
I measured the walls as I was finishing up tonight, after feeling good about everything, only to find one of them undersize in thickness by about 20 thou. I guess my mind got distracted with articles on NPR about mining asteroids and an electric pizza delivery scooter in denmark.
electric pizza delivery scooter
Crap. Well, that's why I have another blank in reserve.
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James Uhrich
Sturnella Toolworks
info@sturnella.com
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joemcglynn
Member
Registered: 04/24/12
Posts: 3
Loc: Santa Cruz, CA
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Joe - this looks great!
I agree with the idea of the sacrificial block, that's a great solution. Plus, if it's in the drag it will double as a sand trap.
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joemcglynn
Member
Registered: 04/24/12
Posts: 3
Loc: Santa Cruz, CA
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I really like what your doing with this project, I wish I'd seen it before you had to cap it.
I wanted to share an approach that I've used in the past, it's worked out well for me. Some of the stuff I make has curves and delicate details that would be hard (for me) to shape in a wooden pattern.
For short runs (say 1,000 parts, maybe more) when sand casting, this is a good approach and not terribly expensive.
I design the parts in SolidWorks, which allows me to add in the necessary draft, check for undercuts, add material for machining, etc. Then I scale the entire model up by whatever the shrink factor of the material is (it's a tool in SolidWorks - it just enlarges the model by whatever the factor is). Probably most 3D modeling tools have something like this.
Then I export the model in .STL format and use a service bureau (I use stereolithography.com) to produce a master. This gives me a plastic master that I can attach to a pattern board and use directly to make parts. I prime and sand the stereolith first to get a super smooth surface. If I want to have multiple copies per mold I can make copies of the master using a casting plastic - if I can get 3 or 4 parts on a pattern board it's a lot cheaper per part.
For larger runs (or bigger/more complicated parts) I scale the model by two shrink factors, produce the stereolith and have a company back east cast an aluminum match plate (the uses up one of the shrink factors). That's more expensive, but the pattern lasts forever.
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Derek Cohen
Member
Registered: 08/20/04
Posts: 4482
Loc: Perth, Australia
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One for Joel or Len ...
http://www.ebay.com.au/itm/RARE-FINE-NOR...#ht_4650wt_1361
For comparison .... or MORE! 
(I hope this is not spoiling someone's surprise ambush).
Regards from Perth
Derek
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Articles on furniture building, shop made tools and tool reviews at www.inthewoodshop.com
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Joel (Tools for Working Wood)
Member
Registered: 01/11/05
Posts: 1100
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Nice picture.
I am personally not a fan of the open handle - I feel much more solid in a closed handled. the 2: width is unusual 2 1/4" being the norm. The 2" norrises I have are a little shorter than the 2 1/4" but not by much - 1/2" maybe.
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Joel
Tools for working Wood
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Gibraltor
Member
Registered: 01/31/07
Posts: 157
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Well, crud! I thought I had made a commitment in the first thread, but didn't check in to WN for 24 hours, and find myself on the outside looking in because I didn't PM in time.
Good luck to you all . . . I was really hoping to have one of these sitting on my plane till.
J. Conrad said:
OK, the list is now CLOSED. Any PM sent after the time stamp of this post will have to be left out of this build.
Have no fear though, if this project goes well, there will be more fun in the future.
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Jason28
Member
Registered: 02/17/04
Posts: 1466
Loc: Doylestown, PA
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I hesitated too long too. Who knows? Maybe they'll do a second run.
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Jason
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LENPAM
Infill Magnet
Registered: 04/03/05
Posts: 9743
Loc: PORT CLINTON,OHIO
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I have one and the No 2 also,but it's a real good worker better then then the A5 IMO.Len
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INFILL MAGNET
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