+DaveJW Posted January 30, 2012 Share Posted January 30, 2012 A little while ago I was looking to improve the 3 secondary adjusting bolts on my 300p. You would think that finding a M4 thumbscrew via the internet would be easy enough, but without paying Bob's prices it was harder than I thought. So I bought a few different bits to play with, stainless steel bolts, wing nuts, locking nuts (mostly ebay I think) and some of these, nylon thumbscrews sold by an aero-modeller (from Kimberley apparently, but I don't know him) :- http://www.modelfixi...ylon_screws.htm The nylon thumscrews were lovely and would be perfect if they were steel - small neat heads with sharp knurling, but I guessed they would be too bendy for this job and so it proved. A steel bolt with a wing nut added and a lock nut to hold it worked but they were very heavy (and shiny), not a very elegant solution. Then I had the idea of cutting off the nice neat head from the nylon thumbscrew, heating the steel bolt and then pressing it into the back of the nylon head. I chopped of a nylon head (easy with a Stanley knife), put in on a board & held the bolt in the flame of the gas hob using radio pliers. The first time I tried it I got the bolt far too hot, resulting in liquid nylon & a small fire. Health & Safety warning: Fire is hot, hot things can burn you and liquid nylon in the eyes probably stings a bit. Subsequent attempts refined the process. I found that as soon as the head of the bolt starts to discolour then it's hot enough to melt the nylon perfectly: I just pressed the bolt in place & held it for a while until the nylon set. The knobs seem to be very well bonded to the bolt heads. Once the bolts had cooled I used a permanent marker to colour the heads black. Thumbscrews in place, they could do with a bit trimming off the length some time. Another idea I've had that I've not tried is a steel bolt with a nylon wingnut, which could be glued into place. Even better perhaps, I've since spotted these, push on thumbscrew caps that fit into a hex socket head bolt, sold by RS components:- http://uk.rs-online....=PSF_119407|cav That would be easy! Link to comment Share on other sites More sharing options...
BAZ Posted January 31, 2012 Share Posted January 31, 2012 That's neat Dave, next time Iam in RS, I'll have a look at those and if they look ok, I'll get some so we can have a look and see if they would do the job. If I remember correctly, we would a M4 x 35mm set screw, pref stainless Link to comment Share on other sites More sharing options...
+DaveJW Posted January 31, 2012 Author Share Posted January 31, 2012 That's neat Dave, next time Iam in RS, I'll have a look at those and if they look ok, I'll get some so we can have a look and see if they would do the job. If I remember correctly, we would a M4 x 35mm set screw, pref stainless Yes that's right Martyn. Link to comment Share on other sites More sharing options...
BAZ Posted January 31, 2012 Share Posted January 31, 2012 I'll keep my eye open, maybe we could get a bulk order together for all Sky-watcher owners, it would work out cheaper that way. Link to comment Share on other sites More sharing options...
+DaveJW Posted January 31, 2012 Author Share Posted January 31, 2012 I'll keep my eye open, maybe we could get a bulk order together for all Sky-watcher owners, it would work out cheaper that way. Good idea! Link to comment Share on other sites More sharing options...
Rusty Strings Posted January 31, 2012 Share Posted January 31, 2012 Lovely job. I did a similiar thing myself using steel M4 bolts, the knurled sections from some old 1/4" metal jack plug cases and araldite. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now