David perry 1 Posted February 28, 2022 Share Posted February 28, 2022 I want to tap a plywood block for wing bolts and assumed (ha ha) its was an M5 bolt. It IS a 5mm bolt of course but M standard it aint... anyone know what these threads are? Quote Link to comment Share on other sites More sharing options...
PatMc Posted February 28, 2022 Share Posted February 28, 2022 David, you might find some useful info in this thread. Also a picture of one of the bolts might help someone identify them. Quote Link to comment Share on other sites More sharing options...
kc Posted February 28, 2022 Share Posted February 28, 2022 (edited) There are both M5 coarse and M5 fine,with a pitch of .8mm or .5mm. It is quite easy to confuse M5 with 2BA. Wingbolts are often 2BA. SLEC sell both M5 and 2 BA wingbolts - if you have tapped it M5 then order some M5 bolts or vice versa. Edited February 28, 2022 by kc Quote Link to comment Share on other sites More sharing options...
Andy Gates Posted February 28, 2022 Share Posted February 28, 2022 If you have tapped a plywood block to hold the wing on, I would be tempted to use a steel bolt rather than nylon and rely on the ply plate to be sacrificial. 1 Quote Link to comment Share on other sites More sharing options...
David perry 1 Posted February 28, 2022 Author Share Posted February 28, 2022 ThNks guys i was being dim. I'll just save these bolts and either buy new or do as suggested and use steel. You know how it is...you want to save tuppence and use old bolts so you spend twenty quid an d three weeks working out how. Too much balsa cement in my youth i think. D Quote Link to comment Share on other sites More sharing options...
Andy Gates Posted February 28, 2022 Share Posted February 28, 2022 I think we have all been there David. Most of my machines I build from scratch, so I have a built in weak point where the fuselage joins the wing. This for me is the 1/8" ply wing retaining plate which is held in with PVA glue. Plenty strong enough for normal flying conditions but if for any reason I cart wheel the machine on the floor, the retaining plate breaks away reducing any damage caused. Quote Link to comment Share on other sites More sharing options...
David perry 1 Posted February 28, 2022 Author Share Posted February 28, 2022 Cheers Andy. This is the Ju88 im restoring so theres a.lot of rework and undoing of bad ideas going on. I wont criticise the build because its over twenty years old and a chap learns a lot in 20 years....but he has left me a few challenges. One of which is the glued but undrilled 1/2inch wing bolt plate!!! D Quote Link to comment Share on other sites More sharing options...
kc Posted February 28, 2022 Share Posted February 28, 2022 It's worth saying that you don't need a proper tap to get a thread in wood - just use a steel bolt and if necessary chamfer the end to help it start ( or in thick wood drill slightly oversize for short distance ) But proper taps are not that dear if you buy from specialst suppliers like Tracy Tools. 1 Quote Link to comment Share on other sites More sharing options...
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