Good idea. It almost looks like he could just go about 1/8" thicker in material. Those bolts are not sticking out the bottom by a thread even. Maybe mill the dia of the hole and use a good bottom tap? May save the machining of the inside if he can just be a little thicker in material ? Guessing the material is already .250+"
I don't know what the specs are for threaded fasteners in plate aluminum, but for rivets in sheet aluminum, Boeing specifies that edge margin is 2.5x the fastener diameter. That's why I picked that number. I would guess that he needs at least the diameter of the fastener of undisturbed metal between the bottom of the hole and the bottom of the screw boss.
Remade the part using 3/8" plate. Bored the center hole on the lathe. transfer punched the holes, drilled 5mm holes close to the bottom using drill stop on the press. Tapped using a M6 but I need a bottoming tap to get all the way down. Have one on order. The one I made came out nicer than the waterjet part. I spent hours laying those out in CAD, took 30 seconds with a transfer punch and the holes are more accurate. You can see the stock donut gasket so I used some longer button head M6 bolts I had. I also clocked the fuel pump so that it will fit in the corner of the square tubing.
Would there be any benefit in radiusing the pump bore so the donut sits down lower and has a larger contact area and you can use shorter screws? Might reduce squeezeout.
probably but I was trying to get the part made. I thought about grinding a radius on a turning tool then got lazy
You shouldn't need to do a radius, just a groove for the o-ring to sit in. Pretty sure the o-ring needs "containment" to work properly. Or does it compress into a groove in the pump? I can't see it too well.
I believe you are correct the groove is in the fuel pump flange on the tank. I'll chuck it up and redo it.
If you have a Machinery's Handbook, there's a good discussion of how o-rings are supposed to work. Gland/groove depth should be 80% of o-ring cross section and 50% wider. You probably knew that, but I like reading the handbook.
That is correct, I always thought that seemed way big until I understood that with a o-ring seal the mating parts still "mate" and the O-ring is just compressing into the groove. I know on break down repairs there were times that we would use a 60/40 rule - as long as it was 60 -40 it would work "good enough" in low pressure situations to get the machine running. In those situations we would also short cut and use the tool on the shelf that was close. We seemed to get lucky 99% of the time, but we also were in the process of making a correct part while the quick fix was being used. BTW- next to thumbing through the McMaster Carr catalog, I too like to read the machinery's handbook. Guess some people are weird that way
I obviously did NOT know that so thanks!! I'll measure the o ring and have at it. +1 on McMaster. I order from those guys all the time. The website is way better than Grainger so I usually order from them. Plus they are next day delivery being in Cleveland and shipping is always very reasonable.
Didn't want to get any closer to the threads. O ring fits in there perfect and I did make it 80% depth of O ring
new project- one for me. This will be hard to believe but my water jet has no jet on timer. The solenoid is a 24V so I decided to mount a timer on the unit and first task is to make a mount, simple : well nothing I do is simple and it seems when ever I take time to do something for myself I hurry and shortcut. This time will be no different. Down to business - Start on my piece of scratch paper and then set up to cut- fast forward to check fit little bit of brake work Well the last two hits are going to require a heavy off set (gooseneck) punch to reach in and give clearance for those ears - not those ears - the ones on the ends Of course I dont have a punch that is that narrow with that much offset - so a new project is started - make a punch starts with this - A few heavy hits and a tool is born - almost - needs more work to fit the holder but it looks like it steps over far enough. I think it will do the job, I will finish up on it tomorrow or on the weekend.
Then the tool needed a holder Now it can bend weld the edges And you have this- just needs a back piece made I had hoped there would be more contributions to this thread. I am interested in what others are making
While I'd like to see others posting up their projects too, please don't abandon what you're posting now. I'm really enjoying it
You guys are doing some excellent work! Thanks for posting up your pics! I've been learning a lot by just following along.
