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Here's a blast plate for you. A little pricey. ~ $150.00:eek: I looked for 36" blades, but they're all notched. Don't think you'd like that. lots of sharp edges...

Thanks, a good find... and free shipping for every order over $2,000.00. Gonna have to coordinate a group order to qualify.

Actually, I think stainless heat diffusers for induction cooktops might work... only they are a little small at 9" to 11" diameter. Ceramic tiles can take quite a bit of heat and come in a variety of larger sizes. I'm planning to have it swing up with the truss, so something maybe 14" to 16" would be ideal.

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How about an AR 500 rifle gong. They can be up to1/2" thick and come in a lot of sizes. Not pricy either.

Ooooooh... hadn't thought of that but a really good idea. Wouldn't even have to be a new one - can repurpose one after its productive life on the range is spent. Will keep my eyes open for one on Craigslist, preferably a larger size. Thanks.

edit... found this one, but 1 1/4" thick, too heavy for me

A used tillage blade is also an option... hey, they wear out, don't they? Or, next time our farmer leaves his equipment in the field... 🔧
 
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Ooooooh... hadn't thought of that but a really good idea. Wouldn't even have to be a new one - can repurpose one after its productive life on the range is spent. Will keep my eyes open for one on Craigslist, preferably a larger size. Thanks.

edit... found this one, but 1 1/4" thick, too heavy for me

A used tillage blade is also an option... hey, they wear out, don't they? Or, next time our farmer leaves his equipment in the field... 🔧

My brother just changed out a bunch, but the reason he changed them is because they wear smaller. I can get one for you, but it’s just about 19”. Flat ones are ~17”. Lemme know. Price is right on them (free). I can bring one tomorrow to QCRC if you get ahold of me tonight
 
Currently just using a 5/16" bolt to lock the legs in their full forward position, may eventually drill these holes out and use a 1/2" bolt with a wing nut.

Did that today... drilled out the holes on both legs and corresponding stop brackets. They line up perfectly for the 1/2"-13 NC bolts and wing nuts. Using the K.I.S.S. principle, just one easy to install bolt to hold each leg in the 120° position. All drilling and welding on base complete. Ready for cleanup, paint, and decals.

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Taking advantage of the warm weather for final paint and photo op. Truss leaning forward slightly because tires not removed, which lowers back end about 6" and brings truss to vertical.

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That's a work of art, Sather! And looks darn functional too. :D
 
Taking advantage of the warm weather for final paint and photo op. Truss leaning forward slightly because tires not removed, which lowers back end about 6" and brings truss to vertical.



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How do you adjust the angle of the launch rod to make sure it's away from the flight line and/or up wind?
 
How do you adjust the angle of the launch rod to make sure it's away from the flight line and/or up wind?

A few options there, still in the wishy-washy phase..

1) Since the pad gets put in the dirt and I want to keep it from getting muddy (yeah, I know, right?), I plan to follow the time honored midwest tradition of placing boards under the feet. Thicker boards in conjunction with thin ones on opposite feet give "shim" options.

2) Still evaluating adding the Bulldog jacks. This will also help in setup and moving, as I let the weight get a bit on the high side and lifting it to pull off the tires is getting to be an issue.

3) I have a few ideas for a simple adjustable mechanism between the pad bottom and the truss bottom. But I have also seen a lot of big pads that don't have windage adjustments at all.
 
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I worried about drilling holes in the truss, as getting them exactly straight on the first try was a requirement. I found from the 1010 rail inside my Patriot battery that it is possible to force a slight curve along the length of a rail with bolts a little bit out of alignment. It probably wouldn't matter with just 2 buttons, but I often use 3 to optimize usable rail length (bottom two are close) and minimize torque on them induced from side wind (top one is as high as I can make it). Luckily, I found this tool to help. The bottom is a vee, so it self aligns on a curved surface. Has a bunch of tall holes to keep bits of various sizes aligned perpendicular to the tube. Voila! The top and bottom holes were already present, 3 holes spaced equally between them are added along a chalk line snapped on the masking tape. Using 5/16" stainless carriage bolts in the rail, extending through the tube and secured with locknuts on the backside. Working alone made it difficult to get all 5 bolts aligned to drop in simultaneously, so I ended up using a jack stand to hold one end of the rail up, dropping it one notch at a time was just about perfect to get the bolts in individually. And finally, nothing finished without a test fit - a 5.5" / 54mm Seahawk booster... first rocket to officially use the pad!

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There is a certain amount of danger working with and around something like this, such as the fear that folding metal pieces function as scissors, and one of the obligations as a designer / builder is to minimize the risk AND to placard what should be obvious dangers to others. (Thank you, tort law). Here is one that literally caught me by surprise… when working around the front side of the pad (taking off the hitch, locking the legs forward, etc) with the truss in place, the 90° outside corner of the up-lock bracket really, really hurts when you stand up too quickly. Luckily it stabbed me in the shoulder instead of my cranium. So, while I had it off to paint, I took the opportunity to cut off the corners. And paint it a bright color.

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Happy Father's Day!

Up-lock bracket installed. Added a "coupler grip" as a grab handle, which coincidentally had the right size and spaced holes, so it fit on the existing U-bolts, which have yet to be cut to length.

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Progress Report...

Sather- will we see this pad at MWP?

YES!!! Hopefully it will be worth the wait, as I started collecting pieces for this in 2012 and my first weld bead was laid on 18 Jul 2017, over 4 years ago.

Final weld session today, three things accomplished. #1 = bracing for tongue, to compensate for torque from offset jack mounting pad. #2 = jack welded on rear. This preserves the "tripod" design, but eliminates ability to "reverse" the tongue as a third leg. The span was determined to be more than adequate to provide a stable footprint, and improves the ability to adjust elevation (for windage), as well as lift the aft end of pad for wheel removal. (I really need to weigh this!) Permanently mounting via welding also eliminated wiggle from the loose tolerance of the factory mounting pad. #3 = welded stainless steel blast deflector. The deflector is a combination angled and horizontal. The largest portion sits at a 30° angle, with the foot coming back to level. The plate will be attached to the base of the truss, and ride up and down with it when raised and lowered. It is also removable if needed for repairs or replacement. Pictured here in roughly its final position. Note the "Remove Before Flight" sock.
  1. mount 1515 rail on truss - COMPLETE
  2. truss uplock - COMPLETE
  3. leg forward position locks - COMPLETE
  4. jack points on legs - COMPLETE (using legs in lieu of jacks, reserved for later upgrade if necessary)
  5. foot on tow bar - COMPLETE
  6. blast deflector - COMPLETE
  7. final paint - COMPLETE (pending minor touch up on added steel)
  8. decals and placards - in progress (fine products from StickerShock23... thank you Mark!!!)
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Drilling holes and final assembly

Love drilling metal. 1/8"pilot hole, then incrementally enlarging holes - 3/16", 1/4", 5/16", 3/8", 7/16", 1/2", and finally 9/16". Slow drill speed, slow cutting, but didn't ruin a single bit. The blast deflector itself really didn't need 9/16" bolts, but the 30° angle brackets I found were already drilled for that so I had to drill the other pieces to match. By the time I finished, I could feel the difference between drilling through bare steel, stainless steel, galvanized steel, and aluminum plates. Blast deflector pieces assembled and installed, and those long U-bolts on the up-lock bracket finally cut to length.

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Finishing touches

1. Put on the first placard... one that I seem to need frequently.

2. Installed a positive rail stop at the bottom of the 1515 rail. Don't want the blast deflector carrying rocket weight in lieu of a standoff. On the unlucky 13th flight of the Gouda Wooshka at LDRS 30, she managed to slip her bottom button off the aft end of the rail prior to ignition, and as a result won "closest to the pad" by default.

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Love drilling metal. 1/8"pilot hole, then incrementally enlarging holes

Have you ever used a stepped drill bit? Normally, I don't like them. In the case of drilling sheet metal, like with your project, they might be just the thing (taking care to prevent the work from spinning, as with all drilling in sheet metal).
 
I actually do have some stepped bits, with a few reasons not to use them. I think I have developed a feel for drilling with a standard bit. Watching the metal shearing off, listening to the motor hum, you get a certain rhythm going. Didn't want to try something new when it really matters, as messing up a hole at this point in the game would really spoil the experience for me. Been planning for and working on this pad for over a decade now, clearly I'm not in a hurry. :)

Most of the metal on this project is 1/4" thick, and a stepped bit can't reach that depth leaving a constant diameter hole. Either the top would be too large or the bottom too small. Unless I had a stepped bit that ended at the exact diameter I needed, but again, there are quite a few different diameter holes in the pad, some as large as 3/4". Which leaves me with stopping at a nominally smaller diameter and opening it up with standard bits anyway. And with the need to keep the bit temp down, taking my time with slow drilling is an advantage.

... my dad taught me how to drill steel when I was a kid. The drill bit is a much harder steel than the steel you are drilling into, and will have no problem shaving off metal as long as it keeps its edge. Keeping the edge is where the bit needs help. Drill a pilot hole first, and keep the bit cool, using a medium oil and keeping the drill turning slow. Torque is your friend, not speed. By switching belts around on the pulleys of my drill press, I got the speed down to a leisurely 240 RPM.
 
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