Valve Lapping

[Normk]

The title was to have been "Valve Lapping Compound" but my fat fingers....

Can't recall posting this one here so aplologies if this is a repeat.

One of the best tricks for gripping partially stripped, or about to be, screws is to dip the screwdriver tip into valve grinding compound which radically increase the grip. This is the equivalent to spreading sand onto an icy road and has to be experienced to be appreciated.

Pick up a tin of grease mixed valve lapping compound or water mixed will do if can't obtain grease mix. It is also very useful to assist an open end wrench (spanner) to grip flare nuts, and such. A few dabs of lapping compound when trying a 6 point socket onto a rounded head.

HIH

Norm

[AJ]

This is an old mechanics trick and it works very well. Just be super cautious where you get that lapping compound when working on machines. You don't want that abrasive on your fingers while handling parts.

On a related note, if you strip a Phillips screw head, you can sometimes mash it down with the round end of a ball peen hammer. Then re-form the cross pattern with the screwdriver bit from an impact driver. Finally, use the impact driver like you wish you had in the first place!

[gearhead13]

Sounds interesting, but I havent found a phillips screw (even loctited Jap phillips) that I couldnt remove with a good fitting bit, a tap or whack of a hammer on the end and plenty of force pushing in. Sometimes a crescent wrench on the driver handle and the other hand just pushing.

[Normk]

Try using an impact driver, whack on the end, or hard end pressure in the screwdriver when attempting to remove a tight screw on a tail light lens or into an easily damaged or flexible assembly and you will see the advantage of using lapping compound to increase the grip in some circumstances.

If one taps or whacks the end of the screwdriver in such cases, the blow can shatter the lens, housing or simply be dissapated by the "give" inherent in the assembly.

It isn't an either/or choice in most cases, simply attempting to select the best option in order to solve the problem.

Most of us have certainly seen screws which couldn't be removed by using the techniques outlined, many of which required extraction by drilling, welding, heating & cooling, etc. A screw which requires more torque to turn than the screw's body can accept will be be extracted by any turning technique. I don't think that you were, in any way, denying that the lapping compound had value but simply expanding on options, right?

"gearhead's" reference to axial impact as a means of loosening reluctant screws is worthy of notation as it can be very effective, expecially if the screw thread fit has some clearance. An end-wise impact delivered as he suggested by a "whack of a hammer on the end" can loosen corrosion welding quite effectively. Much of the effectiveness of an impact driver (a screwdriver-like device meant to create torque onto the drive by the impact of a hammer, as opposed to an impact wrench which is air or electric driven) is due to the enhanced grip provided to tapered bits due to the axial impact on the tool. Regardless, hope the tone doesn't suggest that I'm arguing....

Impact drivers have an additional advantage over straight forward twisting in that they limit the number of degrees to which the drive is turned. If memory serves, the better ones turn the drive 8 degrees under maximum action which is calculated to be less than that likely to twist off the fastener.

Anyone who has used an impact driver or hammer screwdriver understands the effectiveness of such tools for removing tight "Phillips type" fasteners. They are effective but in a lesser way when applied to parallel side drives such as sockets, Allen, Torx.

Question, "Don't people sign posts here?" Just curious as it seems that many/most are blank as to signiture and it seems odd to address someone by a web label. Maybe just because I grew up in the Jurassic?

HIH

Norm

[7981GS]

Question, "Don't people sign posts here?" Just curious as it seems that many/most are blank as to signiture and it seems odd to address someone by a web label.
Maybe just because I grew up in the Jurassic?

HIH

Norm

I, also, don't understand that either.
Up-bringing perhaps? Schools?


Daniel

[hampshirehog]

Also use the right size and spec screwdriver for the job.

[Katarat]

Like JIS screwdrivers made for japanese screws

[sparki]

never used a japanese standard screwdriver in my life... there isn't much a good fitting "std" phillips won't shift along with a impact driver and hammer

[FiremanBob]

My manual impact driver, with the correct size bit, has been a foolproof solution for stuck screws so far on my restoration projects.

[chef1366]

I, also, don't understand that either.
Up-bringing perhaps? Schools?


Daniel

We all use aliases.

[elrico]

Si,no habla=AKA???,no..?

[AJ]

Another thoughtful post by NormK.

I don't sign my posts usually because we post with a screen name, which in my case is the same as I go by in real life, even if the forum software wouldn't let me use "AJ".

Changing gears, does anybody have a good source / price for JIS screwdrivers (total with shipping)? That's one tool I'd like to add to my tool chest. Also, what sizes (equivalent to say a #2 Phillips)?

Thanks, AJ