Kelly, Are you working with foam you have gotten that is thicker than 2”? The other day I stopped at a welding shop that has apparently closed up but there was an enormous pile of old foam board sitting outside that was 4” thick and badly deteriorating from the sun. I thinking that boards in the middle of the stack might be just fine if I could get them.
2" is as thick as can get locally. I'd like to have some thicker stock and can special order 4" 4ft x 8ft sheets but just haven't been sufficiently motivated. If you can get 4" sheet I'd grab it if you know what it is. If it is urethane instead of polystyrene....I'd pass for lost foam casting use. Best, Kelly
Invested in a couple router bits. Carbide round nose and flat bottom. They're advertised as being designed for foam. They have 2.25" cutting length and 4" OAL. Here they are compared to the ones I had. They'll come in handy for cutting 2" foam patterns like the main well. With my old bits I had to extend them uncomfortably far to reach 2"and cut in two or three steps without sufficient collect engagement. Still prefer a shorter stiffer bit if you don't need the cutting length. I'm anxious to try these out. Best, Kelly
Foam cuts so easy compared to metal that stick out is not really an issue as far as I can see. It will be interesting to see how those cutters work. I've just been using straight flute carbide router bits on foam as I use double face tape to stick it down and don't really want lifting force. The foam is so light the air generated by the cutter seems to blow the chips right out. But those cutters look very nice.
Forgot to mention those are 1/4" diameter. I use my bits on much harder materials than foam. My comment about short and stiff being preferred was in that regard. I use straight double flute carbide (insert) bits on foam too and while they cut nice, not quite as nice as the helical bits.....triple flute even better. For foam, if you're making a 2" deep cut on both sides, it still helps to pull the chip up and out. A straight flute bit won't do that.......but you can always make several shallower passes. I have a 1/4" diameter 2" depth of cut imported dual straight flute carbide insert bit I bought for $7 on Amazon because I thought what the heck...$7?. It will chatter cutting 2" of foam......I'd never use it on anything but foam........too flimsy. Makes me winge.....thinking of it departing its shank at 24krpm! Best, Kelly
Here’s what it looked like early this morning. -2F without wind. The heck with that…….I’m casting! I prepped a couple patterns to verify two things. First, to see if the air horn and venturi would cast without vacuum and second, to see how venturi fit in the main well casting. Here are the patterns. Two pours later here’s how they came out. …..and degated. All parts cast just fine without vacuum and just gravity fed which is good news. I’m pleased with that because that booster on the air horn and venturi are thin! So for the second question here’s that venturi. The OD is tapered at 3 degrees and so is the ID of the Main Well where it nests. Here it is nested in the Main Well. Wow, I’m pleased with that too. This is going to work. Here’s the arsenal of tooling. …..and a pile of foam to be converted to patterns. -Big project. ….ya eat the elephant one bite at a time fellas. Best, Kelly
Just for you fellas. It's almost 33 minutes but I discuss the pin router for the first 10 minutes and then cut a carburetor main well pattern during the rest. Best, Kelly
Kelly, Excellent video, and very nice router machine! But I gotta tell you, you are working WAY too hard!! Using CamBam I can program that part in about five minutes from an imported DXF file or 10 minutes from a paper drawing. Cutting time is easily a small fraction of what it takes you now. When you get a CNC router you are going do a whole lot more casting and a lot less pattern making. I’ll bet we are going to see some really amazing work from you! Thanks for posting this video. I learned a lot about your techniques and it has given me some ideas to improve my own foam cutting.
........problem is there is no dxf file. ....and there is no drawing. Just me looking at the original casting and building the pin router templates........but I'll make note of your comment because in the future depending upon your rate, I may be willing to make a sketch and pay you 1/6 (10 minutes) of your hourly rate to model that part and generate the DXF or G-code file because I couldn't do it in 10 minutes. BTW, it sure sounds like you're making a lot patterns and castings. I've seen that peristaltic pump and three of the four CNC router castings......but other than that are you holding out on us? I'm very much looking forward to it. This carb project would have been perfect for it because I'm making 12 copies. The main well is the most complicated. It requires one tool change for the 3 degree taper but other than that it can almost all be all 1/4" bit making it a very good cnc part. The other parts are simple but the CNC I have coming has 35x35 cutting space so I could just mount one board and cut copies across the board.......and that would save a lot of time. I was definitely thinking about how/what I would do in the future. It's like we used to say at the drag strip......you run what ya brung......and I brung a pin router. 2 years ago I would have had no use for CNC machining XPS foam......but then came lost foam casting and I just can't quit it. I must say though, as an avid fabricator, I bought a machine torch for my plasma cutter and I'm also looking forward to CNC plasma capability up to 1/2" thick.......but 90%+ will be 1/4" and under! Best, Kelly
No, a friend who needs 6 for a very special v12 he has built and 4 for me. 1 spare for each of us. No plans beyond that. K
6 on a V12??? You better show us photos! How about just 3 more for my Jag??? I'd LOVE to dump my strombergs! You should be running an SU variant. I know guys that would beat a path to your door with wallets wide open!
Thanks so much for that video, but now I really want a pin router! What a versatile tool, I can see how it would be so useful in a traditional patternmaking shop. I've only seen carb venturis on Webers and Dellortos, was surprised to see them on your Ford carb. Did your carb have different venturis for tuning different motors? Again, thanks for the video, and those castings look great
Pin Router is a common term but if you search Overarm Router you'll get a bunch of hits. It even looks like Shopsmith has such an attachment. I hadn't seen that before. There are several that have mechanical actuators but I'd never consider that and want both hands on the fixture. Onsrud was sort of the staple in industrial/commercial use and you'll find Jet and some imports too. There are a bunch of hobbyist motorized router lifts out there and you could mount one of those on a stiff arm for a fairly inexpensive alternative. I have to tell you though, with a completely exposed cutter, they are bar-none one of the most dangerous machines you'll ever find in a shop and have seriously injured many people. This gave rise to inverted pin routers but with the cutter below the cutting surface, you can't see what is going on and they are less useful IMO. As a rule of thumb, I try to keep my hands at least 4" away and never loaded toward the cutting bit. Smaller pieces just need to be mounted on a larger board or fixture. Since I sit at that machine, I usually use a full face shield with safety glasses behind it because I'm pretty close to eye level but didn't for the video.......and always.......concentrate! There were two different versions of that carb, one with 1 11/16 throttle plate and one with 2 1/4" throttle plate. They had different venturis for the two versions. The (my) 2brl versions will be 2 1/8". They can be tuned somewhat with the Venturis like Weber IDAs.....they are often referred to as chokes by that crowd. Best, Kelly
Well, after a week of business travel, a week of vacation, and a week of the aftermath, I’m back at it. I spent the better part of yesterday sitting at the pin router making patterns. Objective #1 accomplished……….I still have all my fingers! ……….and objective #2: I made >14 copies of each, so that’s 42+ foam patterns not counting the venturis and there's 28+ of those. The blanks are in the box above the patterns. Wow! Glad that part of the project is behind me. Still a lot of detail work and sprue/gating to do. I’ll have to decide how to sprue them. For this many parts I’d probably do at least four patterns per tree to reduce the number of molds, melts, and pours but being Winter, it’s easier for me to handle smaller flasks because I can’t count on dry pavement to dump my large 30 gal flask and need to dump the mold sand on a pan to keep it dry………but I can only get two-on into the smaller flask and that would mean 21 flasks! 10 sounds a lot better to me LoL. I guess I’ll cross that bridge when I come to it. Best, Kelly
Looks like it's 2-on for the throttle body. I figure I can pack two 5-gal flasks and pour both from the same heat. Main wells next. Best, Kelly
Got some decent weather today so decided to cast. I dip coated all the patterns earlier in the week. I poured two cups from each heat except for the last one which was a single. Each cup poured yielded two parts….so four heats/melts. A356 with TiB refiner and modifier. Like my signature says…… I almost poured short on the last one sitting in the front of the group. Each casting is about a pound and the pour ~3 1/2lbs, so two pours very nicely handled with a single heat of the A10 and ended up getting them all successfully cast. Degated and media blasted them. I started at 9:00 AM and finished at 1:00 PM, including set up, clean up, degating, and media blasting, so about 17 minutes per casting all in, not including making the pattern of course. Not setting any records by commercial standards but I was satisfied with the result. Today's bounty.....14 throttle bodies. Main wells come next. Best, Kelly
Thanks Andy. It's a big casting project with much more to do albeit a lot of wash, rinse, repeat..... Nice to hear from you. There's been some good furnace construction threads that have mentioned your build. We miss your input. Best, Kelly
