Most of my patterns are wood and weigh at most a couple pounds. I made some simple draw spikes a while back which consisted of a drywall screw silver soldered into a hole in a 3” piece of 1/4” diameter steel rod. Then I tigged on a “t” of rod about 1.25” long. They worked fine for the last year and a half. But I found that often I wanted to use a 3/4” open-end wrench straddling the upright bar to tap the pattern out of the sand while also putting some upward traction on the spike. That was a bit inconvenient as there was little room to hold onto the cross piece. So, I recently added largish washers by also soldering them in place. I like this new arrangement better. No more dinging my fingertips. No more cussing. FWIW. Denis
I'll admit to using screws on gating systems. any pattern getting more then a couple of uses gets cast in aluminum or Zamak and then tapped for a draw screw. The correct tool in wooden patterns is rapping plates https://www.freemansupply.com/produ...oundry-supplies/malleable-iron-rapping-plates. wood insert nuts are a very viable substitute in most situations https://www.google.com/search?safe=...z-img.......0i67j0i30.iZ3Sf7KYX68&ved=&uact=5 your draw spikes are ingenious!!! and might end up in my tool kit! but they have one fatal flaw, if you insert them too far you will bugger up your pattern, if you go over to AA you can see where i did that on the DESRON 14 plaque V/r HT1
The rapping plates might be a durable solution on many patterns. Thanks for pointing them out. But there is not enough real estate to fit them on the most of the patterns I pour. This is an example. This is an 18” long Baltic birch plywood pattern with the thickest portion being 3/8”. I insert the spikes into the two roundish bosses that you see in the lateral bays of the pattern. (Those same bosses are used as attachment points for handles when the tool cast from this pattern is in use.) Realizing those points would be used repeatedly (I think I have molded this pattern 40 or 50 times so far) I made the bosses from built-up Baltic birch plywood as well. So far they have held up nicely with only slight enlargement of the holes. If the holes in the bosses ever get too loose, my plan is to simply use a small Forstner bit to bore them out over-size and then plug the holes with a new plywood plug. Maybe then I’ll get another hundred pours out of them. ;-) On another “delicate” plywood pattern I pour repeatedly I simply epoxied plywood bosses on the perimeter to use as draw-spike insertion points. Denis
So you Adjusted your pattern design Slightly to allow a draw spike insertion point, well done !!! you can do exactly the same for Rapping plates, it's simply good pattern design. it doesn't matter how perfect your pattern is if you cannot get it out of the sand its FUBAR The rapping plates are quite thin, in the smallest sizes , and because the mounting holes are at a sharp 45 degree angle you can get some serious grip with short screws. I hear you they wont always work. let me get a handle picture you will see why i make some patterns out of metal and drill and tap
Here is a mug handle pattern it’s a split pattern less then 3/8 thick (1/2of the pattern it’s a split pattern )so stupid thin !!!I’ve drilled and threaded it for a 8-32 screw. It catches about 6 thread so pleanty making metal patterns allows this in wood it is still doable by epoxy gluing a brass insert in place and tapping it. Tricky and requires lots of planning. Which I can tell you are well on top of
I (think I) figured out where Denis got the inspiration for his drawspike / draw spike design: Here is my 'unimproved' version from this morning, no washers or split rings were harmed during the build. It is amazing how long a series of events can take to make something so small, locating materials, tools, PPE, and the actual process through assembly then paint. Old Montgomery Wards 110v stick welder and equally vintage 1/16" rods, enough to get the screw glowing orange after a pass on one side. Maybe I will see if the guys will let me use their TIG welder at work... The welds are rough but I figure if I break them in draw spike use then I am doing something else wrong anyways.
Tops, Those spikes should work fine. Not the prettiest, maybe. But, this is not a beauty contest. More interested in gettin er done. I am not sure what the reference is to my spikes that you drew. My ignorance showing, I guess. I often am reminded of a Celtic Cross when I use them. Though, there was certainly no intent on imitating that design. And that comparison is quite a stretch on my part. Denis
Thanks Denis. I hope my post wasn't troublesome, forgot the LOL faces... It's the symbol or 'glyph' from the pop music star Prince as @rocco mentioned. Yeah, it is a stretch... Mine have less of a symbolic quality other than being clumsily t-shaped. I suppose one could think of a blacksmith's hammer or a portion of the logo from the punk band Black Flag. A secondary reason for my post and repetition of drawspike and draw spike is so this thread is easier to find in searches, I missed it depending on whether the term has an included space between draw and spike or not.
