Fuel system question

[fallguy]

If the plan is to use the machine screw to engage the upper threads and turn the bottom screw into the plastic, something might strip ( more than likely the plastic ) as the travel per revolution
would be different unless the threads were the same pitch. I am guessing here, but I suspect that the lower screws would be more like a sheet metal screw with a coarser pitch??
Just thowing it out there

the lower screws are machine screws that go into threaded inserts in the roto moulded plastic tank, so those holes are the same as the thread OD or plus a bit, no threads

the top screws could have been engineered larger, but the lidar sensor is sized to work on the tank which is what I did on the portside to get the thing to seal now (removed the badly engineered focuse tube.

 

[fallguy]

I want to thank everyone again.

I think Phil’s idea to cut a philips tip into a long machine screw has some promise.

 

[Barry]

Gotta get to the lower scew from above the deck.View attachment 205953

Alternatively, you could drill out the upper threaded holes large enough to put a regular screwdriver through to tighten the lower screws and then use the same bolts with nylocks to hold the top unit onto the top flange with a cost of 5 nylocks and 5 flat washers

 

[Barry]

Alternatively, you could drill out the upper threaded holes large enough to put a regular screwdriver through to tighten the lower screws and then use the same bolts with nylocks to hold the top unit onto the top flange with a cost of 5 nylocks and 5 flat washers

I am assuming that there would be enough room under the flange for a nut to lay flat, ie the radius not provide enough flat area for the nut

 

[fallguy]

I am assuming that there would be enough room under the flange for a nut to lay flat, ie the radius not provide enough flat area for the nut

I thought about that already.

I was worried oversizing the holes might made the lidar sensor move around some.

I was also a bit nervous drilling above the fuel tanks, but I can tape off the opening and run a fan to disperse any fumes.

I suppose I could also use bushings to repair the holes and get close to the size.

I think this is my plan B now after I try to make a
Phillips tip in a machine screw.

 

[Barry]

As a machine screw will be quite soft, you could consider just taking a screwdrive which has a shaft size of the existing upper machine screw ( the shaft size could be a little smaller or
larger as the die would cut the diameter to size) and running a die from the top to the bottom of the screwdriver shaft. Depending on the hardness of the screwdriver bit there is a slim chance that you may damage the die but I would think that this would not happen. Then you can be assured that the bit will fit tightly in the bottom screw and not strip the bit to screw head pocket
I would expect that a screwdriver that you buy for 5 bucks would not have a hardened tip

 

[fallguy]

As a machine screw will be quite soft, you could consider just taking a screwdrive which has a shaft size of the existing upper machine screw ( the shaft size could be a little smaller or
larger as the die would cut the diameter to size) and running a die from the top to the bottom of the screwdriver shaft. Depending on the hardness of the screwdriver bit there is a slim chance that you may damage the die but I would think that this would not happen. Then you can be assured that the bit will fit tightly in the bottom screw and not strip the bit to screw head pocket
I would expect that a screwdriver that you buy for 5 bucks would not have a hardened tip

Other than it being 2” riser, this is probably easier than making a phillips tip. Thanks. I plan to try it.