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Post by 92220 on Mar 25, 2019 17:30:42 GMT
I am just working on the rivets around the smokebox front and rear edges and have come up with quite a problem. Has anyone else found that the head sizes vary dramatically even within the same packet of rivets? I have. Luckily when I bought the rivets, I bought 500. I have found the heads vary from .095" dia right up to a few at 0.128" dia! When I fitted the smokebox door ring, I found that a 10 thou variation was about the limit of what can't be noticed. I also found a load of the rivet heads have minute flat edges about half way around the outer edge, just as if the heads have been formed with a rivet snap and it has pinched the edge of the head, between the snap and the material being riveted. I've just spent the afternoon checking every rivet head and have ended up with 5 different batches of rivets each with head diameters within 8-9 thou of each other. I also had to bin a number of rivets that had very out-of-line heads.
Bob.
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timb
Statesman
Posts: 512 
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Post by timb on Mar 25, 2019 19:00:45 GMT
Cant say I had notioced Bob but I dont think I would be throwing any away, rather back to the supplier to ask what tolerance they are made to!
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Post by 92220 on Mar 27, 2019 19:47:43 GMT
Hi Tim.
No, I haven't thrown any away. I just measured all of the heads and batched them up in separate packs where the heads in each pack are all within 10 thou of each other. That is about the limit of a visually obvious variation. It's just a problem I found that might catch others out when riveting up the smokebox end rings which have a lot of close fitted rivets. A variation at the extremities of what found in my batch would look awful if they happened to be inadvertently riveted side by side, or even just a few apart. With a smaller quantity I would certainly do as you suggest, and speak to the supplier about it. As I have ended up with around a couple of hundred of one size and around a hundred each of the other sizes, it hasn't caused me a problem. I shall just make sure they are used where a variation in size is not noticeable because of spacing.
Bob.
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Post by David on Mar 27, 2019 20:37:55 GMT
I have had this too, but not within the same packet. Once they're all mixed together I have to be careful to use ones with similar sized heads. As you say there are some quite outsized ones about.
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Post by Deleted on Mar 27, 2019 23:23:39 GMT
Hi Bob
Could you not profile some tool steel to the required shape (quadrant) to machine each head so that they are all the same size. If using a jig to hold each rivet in the same position in the chuck and just one movement of the cross-slide to make the desired single cut, I don't think that it would take too long to do what you need?
Pete
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Post by 92220 on Mar 28, 2019 8:45:16 GMT
Hi Pete.
Yes that could be done, but it's a real pain to have to do that. I have been thinking of making up a sizing jig by drilling holes of the max and min sizes I will accept for a particular job, in a piece of 1/8" plate, and just try each rivet in the holes. It will be a lot quicker than actually measuring each one before use.
Bob.
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Post by silverfox on Mar 29, 2019 17:48:45 GMT
Bob
I havent done much rivetting, as you can tell if you saw my efforts! but thanks for the heads up on this. As you say a few holes +/- would certainly pay dividends
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