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View Full Version : Self locking flathead Allen capscrews?



wierdscience
08-02-2011, 02:20 AM
Need some in 3/8-16 and 7/16-14,but heres the kicker-
gotta be metallic self-locking,cannot be nylon or loctite.

Any such animal,Google reveals nothing.

lakeside53
08-02-2011, 02:47 AM
Spring or star washer? You can get allen screws with integral spring washers that cannot be removed. Sthil chansaws used them until they moved to torx with serations under the heads.

macona
08-02-2011, 04:05 AM
I have had some SHCSs with kind of a serrated surface under the head to do that. Don't know where they came from though.

Evan
08-02-2011, 06:00 AM
Flathead SHCSs are pretty well self locking without any extra features, especially in aluminum. I have never seen any of the numerous such screws in my mill loosen or in any other application. In aluminum the most common problem is removing them if they have been well tightened.

A.K. Boomer
08-02-2011, 08:08 AM
I know that countersunk (82 degree) allens behave exactly like Evan is talking about and yes especially in aluminum - no need for locktite or anything and in fact if you want to take it apart sometime in the near future you have to keep in mind the amount of torque you apply or it will give you a battle - the longer they sit the tighter they get...

ikdor
08-02-2011, 08:20 AM
Or you could try a trilobular screw such as this
http://www.drillspot.com/products/1013887/approved_vendor_0145139_m3-05x8_din_7500m_flat_z_trilobular_thread_rolling_sc rew

They tend to stay put better than the normal ones.

Igor

A.K. Boomer
08-02-2011, 08:58 AM
I knew those things were going to get brought up --- If they are what I think they are personally I do not like them - I believe ford uses them allot and I think they help destroy the female threads esp. in aluminum - I like full contact in the surface area that's being tightened, there's been many a time where iv removed one of those and found all kinds of thread material along with it, and I don't really work on that many fords, just my two cents.

Rustybolt
08-02-2011, 09:07 AM
They're just flathead allen screws. A SHCS is a different allen screw.

wierdscience
08-02-2011, 09:57 AM
I knew those things were going to get brought up --- If they are what I think they are personally I do not like them - I believe ford uses them allot and I think they help destroy the female threads esp. in aluminum - I like full contact in the surface area that's being tightened, there's been many a time where iv removed one of those and found all kinds of thread material along with it, and I don't really work on that many fords, just my two cents.

They are all using self-threading bolts and screws now on accessory brackets,intakes and exhaust flanges.
With self threading there is no clearance in the threads so none of the traditional bolt removal techniques work very well.
Not all self threading bolts are equal either,the best ones come with the tips pre-lubricated with a waxy never-seize on the tip to prevent the galling.

wierdscience
08-02-2011, 09:59 AM
The star washer idea might be the ticket,the screws will be SS,so they should bite.

RobbieKnobbie
08-02-2011, 10:14 AM
Try SPS / Unbrako. They make a series of all metal locking socket screws in all different flavors. Down side is you'll probably have to buy at least 100 pieces.

A.K. Boomer
08-02-2011, 04:05 PM
They are all using self-threading bolts and screws now on accessory brackets,intakes and exhaust flanges.
With self threading there is no clearance in the threads so none of the traditional bolt removal techniques work very well.
Not all self threading bolts are equal either,the best ones come with the tips pre-lubricated with a waxy never-seize on the tip to prevent the galling.



Your kidding? who's "all" ? and on exhaust flanges? as if they already don't give enough grief pulling threads, I usually don't work on anything new - usually 5 to 10 years behind but when I start seeing this crap show up im going to be really disappointed - it's tough enough staring at a plastic intake manifold when your working on stuff - then again if your intake manifold is plastic then why the hell not anchor it down with pile of crap self tappers:mad:

Forestgnome
08-02-2011, 05:21 PM
Flatheads are self-locking. 110 flatheads lock tighter than the 82 screws.

wierdscience
08-02-2011, 10:09 PM
Your kidding? who's "all" ? and on exhaust flanges? as if they already don't give enough grief pulling threads, I usually don't work on anything new - usually 5 to 10 years behind but when I start seeing this crap show up im going to be really disappointed - it's tough enough staring at a plastic intake manifold when your working on stuff - then again if your intake manifold is plastic then why the hell not anchor it down with pile of crap self tappers:mad:

GM,Dodge,the Japanese you name it.We get a lot of broken bolts from the dealers in town,though not as many as we were getting.I think the added shop time for warranty work was beginning to feedback to the makers.

Then of course all the consumer tools and appliances such as lawnmowers and weed eaters,nearly all self tappers,

The GM dealer has also been sending over oddball metric thread bolts needing taps for them.Wild s---- like 11x1.5 and 7x1.00

A.K. Boomer
08-02-2011, 10:22 PM
So whats the next move to save time and money? snap together?:(

wierdscience
08-02-2011, 10:25 PM
So whats the next move to save time and money? snap together?:(
Lots of glue most likely:(

With the new pie in the sky milage figures they will probably be made of recycled news paper and popsickle sticks and cost $200,000.

rohart
08-04-2011, 07:26 PM
Wierd - 7x1 is a nice size. Meatier than 6x1 and neater than 8x1.25.

I'd like to use it more often and I'm trying to build up some stock of it.

wierdscience
08-04-2011, 09:16 PM
Wierd - 7x1 is a nice size. Meatier than 6x1 and neater than 8x1.25.

I'd like to use it more often and I'm trying to build up some stock of it.
The only problem here is Metric fasteners are most often, even numbered diameters.Anything odd is almost impossible to get.

Worse yet in the automotive bolts the car companies come up with bizzare heads and shanks that only they have and cost a fortune.