nacoran
8554 posts
Jun 23, 2015
5:58 PM
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This is the weirdest thing. I've got a Crossover, and it plays pretty well enough, but the screws (sex bolts/chicago post screws) keep coming loose. All for pairs are constantly coming loose, and in very short order. I just tightened them before spending a few minutes recording three blind mice for another thread and after just a few minutes they were all loose enough that the cover was wobbling.
Has anyone else run into this problem? (I'll scrounge up some replacements, but it seems like a weird issue to have).
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Nate
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First Post- May 8, 2009
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Owen Evans
52 posts
Jun 23, 2015
8:47 PM
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Hi Nate,
I have a lot of Crossovers and each of the brass bolts & screws have been replaced with M2.0 x 10 mm. stainless steel machine bolts & nuts. These fit perfectly and don't tear up your lip near the 1 & 10 hole so don't use any 12 nor 14 mm. bolts
First of all, the brass screws are so soft that they easily strip once tightened 2 or 3 times. Secondly, they are a Posidrive head and not a Philips so it's easy to strip the head. It's just a crappy design and looks good but doesn't work very well.
By the way, the bolts holding the reed plates are also Posidrive. You need a 262/PZ0 x 50 Wiha Posidrive screw driver. If you ever strip the reed plate just get an M 1.6 nut to tighten the M 1.6 bolt.
Hope this information is useful.
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Pistolcat
790 posts
Jun 23, 2015
11:11 PM
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Happened to me too, Nate. The MBD screws are much easier to work with and because of that they aren't as likely to strip, IMO.
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Pistolkatt - Pistolkatts youtube
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SuperBee
2713 posts
Jun 24, 2015
1:24 AM
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i've never had that problem but seems like you've probably stripped them, and Pistolcat's observation may be right. The crossover does need a bit more attention than some other harps to line up for assembly and if not properly aligned perhaps could lead to forcing the screws and thread stripping. seems odd you'd have stripped them all though.
personally i prefer the crossover bolts; means i don't have to change screwdrivers and line up slots.
i've never stripped a thread in one, or in a reedplate, but i have seen plenty of overtightened screws in harps. way back in the 90s I may have stripped a cover plate screw in a Huang. Its true enough that brass is soft; thats one of its charms. you dont have to screw up the plates and covers too tight, much better if you dont. when i attach reeds with screws i take them as tight as i dare, but that's the only place in a harp i want the screw to bind a little, even then its only a tiny bit
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1847
2507 posts
Jun 24, 2015
9:29 AM
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you could use loctite
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barbequebob
2956 posts
Jun 24, 2015
10:29 AM
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One thing you gotta remember is to avoid over tightening the screws because smaller size screws can get easily stripped, and since the reed plates are made of brass, they're even more heavily prone to stripping. On the Hohner harmonicas, the correct screwdriver is a Pozidriv #1 and Wiha makes the best ones around, period. The Pozidriv #0 are the correct screwdriver for Seydel harps.
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Sincerely,
Barbeque Bob Maglinte
Boston, MA
http://www.barbequebob.com
CD available at http://www.cdbaby.com/cd/bbmaglinte
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Gnarly
1395 posts
Jun 24, 2015
11:05 AM
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Ron is selling replacement CP screws that fit a Manji, I bet they would fit the Crossover too.
That's all I know; I am working on harps for a customer and he had replaced the CP screws. They look sharp, but aren't LOL
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MP
3289 posts
Jun 24, 2015
2:37 PM
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I find that harps that use Pozi-Drive screws are often stripped when they arrive. I tighten Pozi-Drive screws on the bottom of the harp as the top screws are the ones that are striped or will strip.
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I'm out of the Biz for a while till I get over my burnout. You can try HarveyHarp or arzajac, or just look the page nacoran put together under Forum Search.
.
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nacoran
8559 posts
Jun 24, 2015
4:36 PM
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Thanks. I probably have some spares around. It's odd that they all went. I wasn't using much torque at all to tighten them (until they wouldn't stay tight!)
1847, may cause more problems, but that stuff does work great, doesn't it.
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Nate
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First Post- May 8, 2009
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1847
2511 posts
Jun 24, 2015
4:54 PM
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works great, just need to use the least potent version
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barbequebob
2958 posts
Jun 25, 2015
10:14 AM
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Pozidriv screws are really fragile and IMO, are better suited more as a machine screw thing with proper machines that are set up so that it becomes almost impossible to overtighten. Cover plate Pozidriv screws are the single easiest to strip, with the main problem being the stripping being where the screwdriver goes into the slot to turn the screw, and tho brass Pozidriv screws have a bit of give and can be a bit more forgiving, stainless ones tend to strip easily if you have a tendency to overtighten them and you have to stop at hand tight and absolutely no further. I'd personally rather see manufacturers use either Phillips or flat head screws because they can withstand more of a beating, but you still have to be careful of overtightening. Manji's uses Phillips head screws and they're far less prone to stripping at where the screwdriver actually goes in.
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Sincerely,
Barbeque Bob Maglinte
Boston, MA
http://www.barbequebob.com
CD available at http://www.cdbaby.com/cd/bbmaglinte
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Gnarly
1397 posts
Jun 25, 2015
10:38 AM
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I like the Suzuki screws overall, but I liked the ones I saw on the hybrid harps I was "improving" too (Olives with Manji CP)--Ron has 'em, whatever they are.
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SuperBee
2714 posts
Jun 25, 2015
2:55 PM
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If you damage the drive in a posidrive head, you can carve a slot. If you're careful, it won't even look bad. Easier in brass. Just don't over tighten, and avoid a lot of problems! And don't force threads if you feel them start to bind.
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JustFuya
792 posts
Jun 27, 2015
11:33 AM
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If the cover mounting tabs are flush/flat before assembly a 'snug' torque works for me. Same for reed plates. If you are using the the assembly process to 'form' the plates you are adding undue stress.
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STME58
1364 posts
Jun 27, 2015
8:28 PM
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How tight is tight on small screws is hard to get a feel for. chart has max torques for screws in various materials. Note how much less torque small brass screws can take that even slightly larger screws.
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STME58
1365 posts
Jun 27, 2015
8:28 PM
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How tight is tight on small screws is hard to get a feel for. This chart has max torques for screws in various materials. Note how much less torque small brass screws can take than even slightly larger screws.
Last Edited by STME58 on Jun 27, 2015 8:29 PM
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