Brian Bleech Posted November 29, 2005 Report Share Posted November 29, 2005 (edited) hello :) I have a stem that one of the threads is completely stripped. I have a tap and die kit, but the last time I used it was a few years ago and I am forgetful.... The stem bolts are 4mm so do: a ) tap a 4mm thread b ) tap a 5mm thread (obvisously use a 5mm bolt) c ) drill out the hole to 5mm and tap it with a 5mm thread d ) drill out to 4.5mm and tap it with a 5mm thread any help would be great :) mike Edited November 29, 2005 by leedstrials Quote Link to comment Share on other sites More sharing options...
Ashley Smith Posted November 29, 2005 Report Share Posted November 29, 2005 (edited) the tapping drill for an m6 screw is 5mm, the tapping drill for a m5 thread is 4.2mm, when you say the stem bolts are 4mm do you mean that is the allen key size you are using? because if it is then the bolts is m5 thread, therefore you need to be drilling 5 mm and tapping m6, the m6 thread should hold a lot better due to the size although by the sounds of it you want to be tapping out to accommodate an m6 screw ash Edited November 29, 2005 by trialnoir Quote Link to comment Share on other sites More sharing options...
JIX Posted November 29, 2005 Report Share Posted November 29, 2005 If your not sure then grab the origonal bolt from the stem and see if it screws into the metal coil. If it fits then the kit u have is fine for the job. If you stripped the thread then u shouldnt need to drill it out. This is simple the experiance I had when I heli coiled my mono trial front brake. Quote Link to comment Share on other sites More sharing options...
Tony Harrison Posted November 29, 2005 Report Share Posted November 29, 2005 James, I don't think he has a helicoil set. It's probably an M5 thread then, so you'll want to go to M6. As Ash said, tapping drill is 5mm, so you should be able to tap with an M6 tap straight away. Not sure if it would be M6x0.75 or M6x1.00 (different pitch sizes), although I'm sure someone here can set you straight. Quote Link to comment Share on other sites More sharing options...
Ashley Smith Posted November 29, 2005 Report Share Posted November 29, 2005 m6 x 1.00 is conventional threading size ash :lol: Quote Link to comment Share on other sites More sharing options...
dave33 Posted November 29, 2005 Report Share Posted November 29, 2005 you take the pitch away from the size of the bolt to get the tapping size, so if you wanna use a 5mm bolt with say 1mm pitch then you need to have a 4mm hole :lol: Quote Link to comment Share on other sites More sharing options...
mr kenny Posted November 29, 2005 Report Share Posted November 29, 2005 mike for the sake of that stem and your face......... get a different stem! Quote Link to comment Share on other sites More sharing options...
nb88 Posted November 29, 2005 Report Share Posted November 29, 2005 Invisible e) take it to a local car/bike shop and get them to helicoil it :lol: Quote Link to comment Share on other sites More sharing options...
shovel Posted November 30, 2005 Report Share Posted November 30, 2005 yeah you would be alot better off helecoiling it, although on something that takes as much stress as a stem, helecoiling is only a short term solution really until you get yourself a new stem Quote Link to comment Share on other sites More sharing options...
Tony Harrison Posted November 30, 2005 Report Share Posted November 30, 2005 helecoiling is only a short term solution really until you get yourself a new stem Rubbish. When Yamaha first started making their TZ road racing (motorbike) frames out of aluminium, they heli-coiled the threads because they needed the same strength as a thread in a steel frame. A helicoiled thread is stronger than a normal thread. Why? Because it is a larger diameter thread and the insert stays still. I stripped both bolts out of a stem and I had it helicoiled and then I could really wind the bolts up tight. Quote Link to comment Share on other sites More sharing options...
Brian Bleech Posted November 30, 2005 Author Report Share Posted November 30, 2005 cheers for the help guys! yeah i need to tap it with M6 thread and I can't find that tap :lol: ahh well may look into getting it helicoiled, because other than that its a perfectly fine stem. How much is it too get it helicoiled? mike Quote Link to comment Share on other sites More sharing options...
JIX Posted November 30, 2005 Report Share Posted November 30, 2005 Buy a kit from a hardware store. Maybe B&Q or somewhere like that might sell them. Its very easy to do. There will be instructions on how to in the box. Its not worth getting it done by someone else. Quote Link to comment Share on other sites More sharing options...
Brian Bleech Posted November 30, 2005 Author Report Share Posted November 30, 2005 aahh cool if its piss to do - i will get my dad to buy one :lol: he will able to get one at trade :lol: thanks for the help Quote Link to comment Share on other sites More sharing options...
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