lost webpage - using weedwhacker string for "thread locking" - ie nylock
Aug 21, 2010 5 Replies
D
des bromilow
G'Day,
I recall seeing a webpage where there was some pictures of a threaded device which used a piece of weedwhacker string pressed through a hole to serves as a form of threadlock - similar to a nylock.
Now I need something like that in my design, and I don't recall the website. Does anyone know the website page I'm describing? What is the URL?
I'm making up some little machine jacks for settign a sinebar, and they tend to move a littel when they are maneuvered into position, I'd prefer the thread lock action as opposed to the bulk of a lock nut.
Thanks, Des remove the german anti-spam device if direct replying
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A
anorton
I haven't seen that webpage, but what also might work is Vibra-Tite VC-3. It is a thread locker you apply before assembly and let dry. It dries to a soft plastic coating that lets you adjust the scew but keeps it from vibrating loose.
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F
F. George McDuffee
========== That sounds like the KFR Omnipost tool holders. They use this method on the vertical adjustment screw and it seems to work well on the few holders I have made.
see
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To see some pictures of this tool holder in the flesh click on
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-- Unka George (George McDuffee) .............................. The past is a foreign country; they do things differently there. L. P. Hartley (1895-1972), British author. The Go-Between, Prologue (1953).
D
DoN. Nichols
I don't remember a website -- but I do remember posting here the advice to another regular's question the suggestion that he try that technique. I've seen commercial screws with such inserts, and when I've needed a locking feature in existing screws, I've used the technique. I simply would find some nylon string of a reasonable size for the screw size, drill a hole perhaps between 1/2 and 3/4 the diameter of the screw, shove in the nylon, and cut it off flush with the crest of the threads. For really small nylon string -- try either fishing line (leader perhaps) or Classical guitar strings.
For somewhat larger -- aside from weed whacker strings, you might get some scraps from a place which restrings tennis rackets.
The other regular tried that, and it did what he needed.
Why do you need a web page to do this? Just do it. :-)
Setting a sinebar on jacks? How do you get the precision you want? Normally, I use a stack of cheap Chinese gauge blocks -- though I might try an adjustable parallel if I needed a variable which I would set to a given dimension (usually using a micrometer). I certainly would not use machine jacks.
Enjoy, DoN.
D
des bromilow
Hello DoN. Nichols,
Thanks!!! _ I was pretty sure the string went through the bolt (as opposed to the nut) but wanted to be sure... Why do I want the webpage? - I like to give credit for where I borrow ideas
- simple as that. When I write up this project, I'd like to be able to point out this little tip and say where I got it from.. right now I can say it came courtesy of the folks at RCM, but it'd be nice to say where else it came from.
The machine jacks will be used to set a sine bar because until I have sets of guage blocks, etc, machine jacks set to a vernier caliper will be better than nothing.
Thanks, Des
D
DoN. Nichols
Normally -- you don't want the string all the way through. It is too likely to fall out the other side. I would probably use a minimum of three or four times the depth of the threads for larger bolts, and if there is a lot of load on the bolt, you want it to engage near the outer side of the nut so you don't weaken the bolt too much.
O.K.
Well ... *I* got it from screws illustrated in the PIC catalog (they make precision gears and such) and seeing some used in aircraft style construction (my employer was making flight simulators).
I passed it on in the newsgroup.
Others probably have as well.
But it seems to be semi common practice in certain fields. (There were also aircraft anti-vibration nuts with a nylon washer captive in the top of the nut under a rolled lip.)
Hmm ... Chinese gauge block sets are cheap enough. Look at eBay auction # 180546181693 ($40.00 buy-it-now for a 36-piece set, which should be sufficient.)
The Chinese sets (which this may or may not be) are supposed to be accurate within 50 u" (micro-inches -- 0.000050"). I would not use my good B&S set of "Jo" blocks under sine bars, except perhaps for precise gauging setups, not for machine setups.
A space block set may do just as well -- depending on how precise you are trying to be.
At the moment, the search string which has the least clutter on eBay for this is:
gauge block set* -hoses -manifold -"sight glass"
the last three '-' entires are to keep air conditioning manifolds out of the search.
If you want a cheaper way to go -- to continue transferring settings from calipers to the sine bar -- do another eBay search for:
adjustable parallels
Which can be adjusted to various sizes within their range, and at least will have contact surfaces like a gauge block -- if not as smooth. A machinist's jack does not have the flat level surface which a sine bar expects to rest upon.
Look carefully at the photos in auction # 300457608090
You will see that each parallel is split in two along a diagonal line, (and are held together by a dovetail between the two, not visible from the plain view but marginally visible by the angled view at the ends.
Each has a screw (or sometimes two, depending on size) to lock it as the selected setting.
While these are made for transferring measurements, you still have a loss of accuracy with every transfer.
And you at least want a micrometer to set them to, not a vernier caliper if you want accuracy.
Enjoy, DoN.
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