Author Topic: Clearance Holes  (Read 11025 times)

Offline Ramon

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Re: Clearance Holes
« Reply #15 on: January 07, 2014, 11:25:22 AM »
Hugh
Mike is quite right here - I'm afraid I've mislead you.

Though it could be - I was trying to convey the opposite to reasonable clearance holes - It is very unlikely a stud would ever be fitted to ensure alignment, dowels, as Mike said, would of course be used.

Bolts on the other hand can be 'fitted' for location purposes - I have a few somewhere with precisely ground shanks which were used on press tools.

Ramon
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Offline sshire

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Re: Clearance Holes
« Reply #16 on: January 07, 2014, 11:54:54 AM »
Other than historical accuracy, why would threaded rod be "frowned upon?"
Will the stud police show up with a search warrant?
"Sir, keep your hands where we can see them and remove that cylinder head."
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Stan

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Re: Clearance Holes
« Reply #17 on: January 07, 2014, 01:11:08 PM »
Other than historical accuracy, why would threaded rod be "frowned upon?"
Will the stud police show up with a search warrant?
"Sir, keep your hands where we can see them and remove that cylinder head."

 :lolb:

Now that's funny!.

Dave
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Re: Clearance Holes
« Reply #18 on: January 07, 2014, 01:28:36 PM »
Studs are often used on large parts as its easier to align the part and Hold it in place when placed over stud....imagine if you will the vertical steam chest cover weighs say 300 pounds....or about 150 kilograms  8)....it would be much easier to hang it on the studs and get a nut on than to try to fight the weight hanging on a chain fall while you try to start a bolt.  Or....a 600 pound cylinder head cover that's off....just a little bit...and you can't get the bolt to start....your not moving the head with your hand, you have to get a pinch bar.. to move it.    So a set of studs removes the problem.

So in real life the fit would be pretty loose.   and there would be lifting eyes on the part....

Dave
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Damned ijjit!

Offline peatoluser

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Re: Clearance Holes
« Reply #19 on: January 07, 2014, 04:31:19 PM »


...not forgetting that they are really useful to hang the gasket on while you sling up thesteam chest!


peter

Offline sshire

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Re: Clearance Holes
« Reply #20 on: January 07, 2014, 04:32:30 PM »
Thanks, Dave
I can see the issue with a "real" part weighing hundreds of pounds. With our tiny engines, I can't see any issue with threaded rod.
My philosophy is:
1. Machine everything to appropriate tolerances.
2. Finish where it's visible. I'm not of a mind to highly polish the bottom of a part that attaches to, let's say, the base.

So, if the visible part (after assembly) of a stud or threaded rod is only the thread, I don't see myself making a stud when I've got every size fully threaded studs from 2-56 thru 10-32. All 1.5" long. All from McMaster. At a few bucks per hundred studs.
Of course, everyone knows what's right for them.
A good thing to know would be, when is a stud necessary for correct operation of a model engine? This would be a valuable addition to stuff I've learned.
Best,
Stan

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Re: Clearance Holes
« Reply #21 on: January 07, 2014, 04:38:28 PM »
That's the beauty of this hobby Stan....You get to be the President and Chief Engineer  of your own Engine building company.....What the boss says....go's!

 :cheers:
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Re: Clearance Holes
« Reply #22 on: January 07, 2014, 04:47:02 PM »
Jason might be able to answer this better than I, but think scale, multiply that scale to get full size and weight...now how would you want to mount it?

Well....that might make sense.    The other is ....like with Jo's build...she's trying to replicate all the details of the original....so she's using studs

The other thing to consider, you probably go thru far less material making a stud and a nut than you would if you made a bolt.   Back when you needed to MAKE all the fasteners for your engine...that might be a serious thing to consider.......

Dave
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Damned ijjit!

Offline mklotz

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Re: Clearance Holes
« Reply #23 on: January 07, 2014, 04:58:51 PM »
Stan, you think anality (yeah, I created that word) about studs is something.  Ask the Brits about "thread counter" judges who deduct points during judging for having the "wrong" number of threads showing above the nut.
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Re: Clearance Holes
« Reply #24 on: January 07, 2014, 05:04:09 PM »
Nice word Marv!....I like it!

Dave
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Damned ijjit!

Offline sshire

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Re: Clearance Holes
« Reply #25 on: January 07, 2014, 08:28:17 PM »
 Marv
"Anality" has now been officially added to the MEM lexicon.

I get what Jo is doing. In many cases she is making as close to a perfect, small scale reproduction of existing engines. Much (if not all) of what Elmer designed never existed as a working, full scale engine.

I, on the other hand, am just hoping that the damn thing runs. Thread counters be damned! I didn't know that they went to such lengths to exercise their anality.

 

Best,
Stan

Offline Jo

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Re: Clearance Holes
« Reply #26 on: January 07, 2014, 08:29:10 PM »
I've bored people on studs before so I won't repeat it  :disagree:

If you are building a model engine and all you want is a fixing you might as well use cap heads... but some of us look for something a little more realistic in our models.

I hate it when you buy a bolt and it is threaded the entire length of its shank. Where did these people come from? A bolt should only be threaded for 2 1/2 times the diameter of the bolt, the plain part of the shank is there for a good reason  :ThumbsUp:

As Farmboy mentioned studs can be threaded to not only take account of the material of the main item in which it is attaching but have a different thread on the other end to allow for fine torque adjustment. Now a good stud is screwed into the metal for a distance of 1 1/4 to 1 1/2 time the diameter, whilst the tapping hole should always be drilled to a distance of at least twice that of the diameter of the thread.

Don't forget that the distance of studs from the edge of the metal should never be less than 5/8 D much better greater than 3/4 D.

As for the dreaded 1 1/2 threads sticking out well that is there for good reason: it is all to do with the lead needed for the thread cutting, the first bit of thread is not to full depth. An if you are a manufacture the last thing you want to do is waste metal on fastenings by leaving the threads over length. It adds to the cost of manufacture and the weight of the final item and on the sorts of things I work on every gram counts  ;)

And of course there is that little problem about lock nuts: should the thin nut be on the top or the bottom :lolb:

Jo

« Last Edit: January 07, 2014, 08:32:55 PM by Jo »
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Offline Jasonb

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Re: Clearance Holes
« Reply #27 on: January 07, 2014, 08:37:35 PM »


I hate it when you buy a bolt and it is threaded the entire length of its shank. Where did these people come from? A bolt should only be threaded for 2 1/2 times the diameter of the bolt, the plain part of the shank is there for a good reason  :ThumbsUp:

In that case you have bought a screw not a bolt, most of the ME suppliers sell hex head screws thats why they are fully threaded, I think most people buy the screws and cut them to the length required which if it were a bolt may remove too much thread.

J

Offline Jo

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Re: Clearance Holes
« Reply #28 on: January 07, 2014, 08:43:14 PM »
I think most people buy the screws and cut them to the length required which if it were a bolt may remove too much thread.

:facepalm2: You might as well use threaded rod  :ShakeHead:

Jo
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Offline Jasonb

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Re: Clearance Holes
« Reply #29 on: January 07, 2014, 08:51:59 PM »
But that would look wrong where a bolt/screw was needed, plenty of bolts on a traction engine which would look out of place if you had studding with a nut on both ends.

J