thread class of heli-coil screw lock
thread class of heli-coil screw lock
(OP)
Hi all,
I was wondering - "standard" Heli-Coil insert thread class is defined at 6H tolerance
when we are talking about screw "lock" insert version - GO gauge does not pass, which is rather normal situation because it's tighter
I am wondering - how to verify if thread class in screw lock version is correct? (assuming it shall be also 6H or this assumption is wrong) ?
thanks in advance
I was wondering - "standard" Heli-Coil insert thread class is defined at 6H tolerance
when we are talking about screw "lock" insert version - GO gauge does not pass, which is rather normal situation because it's tighter
I am wondering - how to verify if thread class in screw lock version is correct? (assuming it shall be also 6H or this assumption is wrong) ?
thanks in advance





RE: thread class of heli-coil screw lock
A locking helical thread insert has a coil bent into a hexagonal pattern that violates all the screw tolerances. The locking section does not comply with H6 or anything else. The rest of the insert might.
Any time I have specified locking helical thread inserts, everyone has hated me for it.
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JHG
RE: thread class of heli-coil screw lock
Standard practice is to inspect the threaded hole before installation of the insert. It shouldn't be necessary to gage the installed insert.
I believe HeliCoil recommends class 4H5H for screw-locking applications. Their catalog has more detailed information about tolerances and gaging.
pylfrm
RE: thread class of heli-coil screw lock
RE: thread class of heli-coil screw lock
Tunalover
RE: thread class of heli-coil screw lock
We had problems in the distant past with helical thread inserts that did not work. We bought helicoil thread gauges. We removed the thread inserts and we inspected the holes. It turned out to be the vendor's fault. He was using old, dull taps.
The OP wants to know how you determine that a locking insert meets H6 tolerances. As noted above, I claim that the insert works by violating this tolerance. You cannot verify that it meets H6, because it doesn't.
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JHG