Technical I need to know about blind screwing

LMAO. That's too funny Ray. You just can't argue with logic

 

What I do when cutting a bolt sorter, or putting a taper on one, is put a nut on it first...cut/taper, then take the nut off, threads will come back to work. If they seem thin (threads) I touch them up with the thread file.

 

Look in Mcmaster Carr or other vendors for Dog Point bolts

 

I agree with you and routinely do the same in that specific operation......shortening a bolt.
However, that is not what the issue is in the OP’s case. His concern is getting the long bolt to enter the thread squarely in an assembly that may have some distortion as a result of welding the assembly.

What @squirrel and myself and others are suggesting is the use of a ‘piloted’ tip on the bolt to insure the correct alignment of the bolt threads when entering the captive nut.

My comment was intended to counter the suggestion by other posters of using a tapered thread on the bolt. A tapered thread at the bolt tip would encourage, if not ensure, cross threading of the bolt in the captive nut if there is any misalignment present.

Think about it. Common thread taps, and dies for that matter, along with self threading fasteners, all use tapered threads to facilitate the formation of threads. Usually new threads in the material, but if threads already exist, one has to be very careful when inserting a tap or self threading fastener to prevent cross threading. The piloted fastener is the best approach to eliminating cross threading in the OP’s circumstances.

Ray

 

Squirrel and Ray I agree with you both and the logic is very sound but you have to remember we are in the world of " I've done it that way and it works fine". I would like to see what he is working on.

Pat

 

I have to agree with Pat. I learned a long time ago that sometimes you need to take off the "engineer hat" (hard to do) and put on your "hot rodder hat" If I'm going to over-think a problem, I'm far better off concentrating on the simplest solution, rather that over engineering it...sort of an Occam's Razor (Parsimony) situation.
5 minutes on the belt sander making tapered bolds...or an hour setting up the lathe and making "dog point" bolts ? Simplicity will be my first choice

 

Most of have access to a belt sander but not many have access to a lathe.

My education for this morning is "dog point bolt" I thought they were just easy to start body bolts.

 

how about 5 minutes on a grinding wheel removing all the threads off the last half inch of a bolt, and rounding the end?

Your two proposed solutions are not the only ways to do it. Look up "false dichotomy"

 

My education too, as I was unfamiliar with the term ‘dog point’, but just looked it up. It is what I and others have been advocating for the OP’s application without having used that description by name.

As for lathe vs belt sander......there is absolutely no reason I can think of that would prevent forming a useful ‘dog point’ on a bolt with careful use of a belt sander. A lathe, though useful, would not be necessary for this relatively simple task.

‘re ‘overthinking’.........if I am going to spend time thinking about solutions, I’d rather explore the whole range of options, then choose that which is adequate for my immediate needs and within my means to produce. If I error in my choice, I’d rather it be better than needed rather than prove inadequate.

Ray

 

I understand your point. I am very aware of the mindset you refer to. However, while I ‘remember’ it, I don’t have to accept it, or more correctly, adopt it. In most cases where that statement is invoked, the person may not have a sound basis of comparison between the results of properly done vs half-assed.

For example, suspension principles and design, wherein scrub radius or bump steer or other maladies are either unrecognized or ignored because they ‘can get away with it’.....i.e., the car goes roughly where it is aimed. When the errors are pointed out, there is resistance to even admit the shortcomings, must less put the effort into correcting them.

All that said, I have no illusions it will change anytime soon.....or ever.

Ray

 

Amen Ray.

Pat

 

Geez Squirrel & Ray, You guys gotta lighten up ! All I was trying to convey was a semi "tongue in cheek" dissertation on how I get things done.

With all due respect @squirrel, "false dichotomy" does not apply here. To illustrate my point on "simplicity, I simply used 2 examples of what I believed to be the easiest, and the hardest solutions. Nowhere did I state, or imply those were the only 2 solutions

And Ray, I hate to say it, but your quote above is almost exactly opposite of how I approach things.
Yesterday I had to make an odd angle plate/bracket to adapt a '40 Ford wiper motor in my'36 Cabriolet. Took some measurements...saw where/how to mount it and what it had to do. The only real thought I had to put into it was what's the fastest, most efficient way to make it...so I can move on to the next project. 45 minutes later, welds ground, holes drilled, painted, mounted and working wipers. No over-thinking or over-engineering required

 

I use your approach too when the solution is completely obvious and uncomplicated. However, I don’t limit myself to such simple tasks.......

Seriously, Jack, I agree.....if the problem is relatively simple to solve, no need to overthink it. But there are many projects that are a bit more involved. Some times it pays to think it through before rushing to the ‘fix’ because you begin to notice other less conspicuous factors. Do it right once and be done.

Ray

 

I'd rather spend an extra fifteen minutes thinking, than an extra hour making...usually.

It usually takes me several ideas before I come up with something I really like. I really prefer to sleep on a problem, if I can. I seem to be better at coming up with solutions, when I'm not thinking about the problem.

 

You'll get the general idea by just closing your eyes in the daytime and "feel" your way till you are done.

 

could you possibly weld a length of tubeing on top of the cage nut ,between the parts,to guide it to the threads

 

Well, you don't have to turn off the lights...