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My neck flanges have been updated as arriving tomorrow. So I can practice boring to a close fit while retaining squareness to the shaft. [Orthogonality. ] I may need to turn a stub mandrel to spin the flanges by their bores to check flange run-out. If the flange faces have any "wobble" when spun in the lathe then the shaft will effectively describe a circle on the sky instead of a point when driven at a more normal sidereal rate [A speed of 1 rev per 23h 56m 04s.]
After considerable online research I have decided to use Loctite 638 bearing retainer to ensure the flanges stay put on their shafts. So I have ordered some 638 online from eBay UK and can expect it just after the weekend.
YouTube videos show Loctite 638 being used for some seriously heavy duty retention tasks on machinery in a massively different scale to my far more humble needs. Loctite 638 is also fine on stainless steel components.
I shall leave the application of this industrial adhesive for as long as possible to avoid having to withdraw the shafts completely from their bearings. This isn't so much difficult as fiddly to get the self-aligning, flange bearings correctly orientated to allow the heavy axis shafts to slide freely. A good bevel on the shoulders of the shafts helps initial insertion into the bearings. The shafts weigh so much that they try to sink at every opportunity.
Pretty, but the wrong size! The 48.3 does not refer to the bore diameter [as I has assumed in error.] Despite being stamped 48.3 these measured 42.4mm across the bore. I have contacted both my supplier and the major importer for bore measurements of alternative neck flanges sizes. Searching online produces either no information on bore size or numbers which do not even match the pair I received. I do realise that these flanges are intended to be welded to standard pipes with nominal designations. I just wish the bore size was routinely listed alongside all the other dimensions published online! How can the bore dimensions of flanges sold worldwide be a trade secret?
A phone call to a distributor produced some interesting news. The DN50-60.3 has a bore far too large for my 50mm shafts at about 54.5mm. But there is a second type of DN50 neck flange. A DN50-55.8 has a bore very close to 50mm. My supplier is hopefully ordering this slightly larger 165mm Ø flange. The DN50-60.3 is very little different in price compared with the 48.3 so it should not be too much of a shock.
Another update: My thread on CN has raised some serious doubts about the efficacy of Loctite 638 retaining compound. Dropping a heated flange over a cold shaft would produce a good fixing, once it cooled, but still needs locking screws for security. I wonder whether I could turn a split cone in brass? This would wedge itself into a turned tapered hole in the flange face as the flange is forced into contact with the axis housing. Probably difficult to impossible to control the gripping power without leaving a protrusion. If the new fit is too loose I may end up having somebody put a weld bead both sides of the flange to fix it securely without resulting flexure on the shaft.
Pretty, but the wrong size! The 48.3 does not refer to the bore diameter [as I has assumed in error.] Despite being stamped 48.3 these measured 42.4mm across the bore. I have contacted both my supplier and the major importer for bore measurements of alternative neck flanges sizes. Searching online produces either no information on bore size or numbers which do not even match the pair I received. I do realise that these flanges are intended to be welded to standard pipes with nominal designations. I just wish the bore size was routinely listed alongside all the other dimensions published online! How can the bore dimensions of flanges sold worldwide be a trade secret?A phone call to a distributor produced some interesting news. The DN50-60.3 has a bore far too large for my 50mm shafts at about 54.5mm. But there is a second type of DN50 neck flange. A DN50-55.8 has a bore very close to 50mm. My supplier is hopefully ordering this slightly larger 165mm Ø flange. The DN50-60.3 is very little different in price compared with the 48.3 so it should not be too much of a shock.
Another update: My thread on CN has raised some serious doubts about the efficacy of Loctite 638 retaining compound. Dropping a heated flange over a cold shaft would produce a good fixing, once it cooled, but still needs locking screws for security. I wonder whether I could turn a split cone in brass? This would wedge itself into a turned tapered hole in the flange face as the flange is forced into contact with the axis housing. Probably difficult to impossible to control the gripping power without leaving a protrusion. If the new fit is too loose I may end up having somebody put a weld bead both sides of the flange to fix it securely without resulting flexure on the shaft.
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