Greetings,
I've noticed that a lot of Sinar Normas out there are missing knobs that control rise and fall. I am missing two. I still have the brass bolts, but the 4-pronged knobs that were pressed on to the knurled bolt head have been lost.
Has anyone found a suitable replacement for either the knob or knob with stud? I have checked Grainger, McMaster-Carr and others, but can't find the right fit. Help is appreciated.
Best,
Jonathan
Had the same problem. Found one used OEM set of the knobs but the asking price was outrageous. Finally went to our local ACE Hardware store and found 2 very inexpensive knobs which I drilled out holes to epoxy the brass bolts into. Replacement knobs are larger than the 4-pronged knobs and I think actually are easier to use. If you go this route just make a jig to align the stud at a right angle to the knob when the epoxy is hardening up. First time I did this I tried to do it by eye and the knobs looked and were off axis when I screwed them into the standard. Second time used a jig and bolt was perfectly on axis.
I don't have anything to check metric thread sizes but if it's the right size a possible alternative would be a 4mm thumbscrew.
https://www.amazon.com/uxcell-Comput...27ZNQPGG22J640
jeff
Coat an original knob with a silicone release spray, press it into a block of modeling clay, remove it, pour epoxy into the mold, stand your bolt in it. JB Weld is tough stuff, you might try that.
Thank you... now I can replace 2 broken knobs on one of my Linhof Heavy Duty Tripods... OEM replacements was told were no longer available. Knob color will be different but bothers me not the least.Originally Posted by Peter Gomena
Jonathan - here’s a workable solution. Since I was about to leave for my local Lowe’s store anyway, I decided to remove this screw/knob from one of my Normas so I could check the thread size with their tool that was hanging on the wall there. It fit nicely into the M5-.8 standard metric receptacle. Then I went to McMaster’s website and looked for options; I’ve come up with a way to make your own replacement:
They have round knurled plastic knobs close to the size of the OEM knob that can be had in black (or other) colors. These knobs are designed to be pressed onto the head of a standard socket-head cap screw; you could jig the screw so its axis is perpendicular to the knob and press it in with a vise; I’d suggest a bit of epoxy in the cavity of the knob before pressing to provide even more strength (I suspect all the missing knobs out there are a result of applying too much torque on them and breaking the bond between the screw and the knob – It’s a pretty tiny screw). Here are McMaster’s part numbers for both the screw and the knob that should work for you.
Screw – p/n 90128A232. Enter the p/n in the search box at the top of any page and it will go directly to the screw. Clicking on “Product Detail” at the top of the dropdown window will show All details. It’s the same length as OEM. A pkg of 100 for $7.79 gives a bunch of spares.
Knob – p/n 91175A063. Use same method as for the screw to see ALL details. A pkg of 50 for $10.20 also gives many spares if you ever need them.
The only thing left to do is figure out how to put a “dot” of rubber on the tip of the screw’s thread, like the one on the OEM thread – to prevent marking up the softer aluminum post on the standard.
Hope this helps.
Jerry, you've identified a very critical point above. The rubber tip is an absolute necessity to avoid damaging the post.
I'd love to know how tips can best be applied so they remain in place at the tip of the screw - i.e so as not to detach as pressure is applied. Ideally, the rubber should be fairly hard and embedded in the screw tip. ( Not so easy )
I'm needing replacements as well.
I know just enough to be dangerous !
Dennis,
I've been giving this some thought and have put an idea together (screenshot attached) for putting a rubber tip on the screw. It's a delicate process due to the tiny dimensions, but doable with care, I think. Note the disclaimer. After the screw and knob have been obtained per Post #6, the attachment then takes over the process. Lengthy links in the attachment (which can't be copy/pasted) are provided here:
Rubber product: https://www.amazon.com/gp/offer-list...&condition=new
Hex nuts: http://www.homedepot.com/p/Everbilt-...0178/202249551
If you attempt it, all I can say is good luck. Sorry the instructions are kinda tiny to read; can't seem to get a magnified version to work. Never had that problem before.
Cheers,
Jerry
Last edited by Jerry Bodine; 22-May-2017 at 17:19.
I don't know the particulars of the Norma knobs, but there are plastic tipped set screws available. Perhaps they can be made to work? Search for "nylon-tipped set screws" at www.mcmaster.com
Thanks for the idea. I missed those on McMaster's website; might work and be a lot less fidgety to put together than what I've proposed. Always thought nylon to be fairly slippery stuff, but then it's used in locknuts and wouldn't do its job there if slippery. So it may be easier to use them. The only issue might be knowing the depth of the knob's cavity in order to select the best length of the setscrew. Since the exposed length of the OEM thread measures 8mm, and guessing the depth of the knob's cavity is no more than 4mm, a 12mm setscrew length should work ok. If the setscrew is a bit long it wouldn't be a problem. SO, placing the setscrew in the cavity (and somehow ensuring perpendicularity) and filling the cavity with epoxy would be a workable solution and quite a bit cheaper.
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