# Preventing damage by metal on metal



## Bogstandard (May 2, 2008)

I know that it isn't much of a tip, but having read where a few of you are having trouble with standard locking screws, anywhere that tightening a hard screw onto a sliding face will cause damage. I thought that I would bring these to your attention.

http://www.jwwinco.com/products/section11/gn913.3/index.html

This was one of the first to be thrown up by google when I searched for 'brass tipped screws'.

I use these types, and also make my own for special applications. It does save on damaged parts. But not really effective in very high torque situations.
You can also easily emulate them by making a little sacrificial slug of brass, nylon or aluminium that is put into the hole before inserting the locking screw. 

John


----------



## DickDastardly40 (May 2, 2008)

I've used a small ring of copper wire for this in the past where a set screw bears on a thread, which seemed to work OK for a quick and dirty fix.

I considered using a slug cut from a solid copper earthing rod but couldn't find one until too late, when I did find a supplier by chance the price,  blimey!

Al


----------



## Divided He ad (May 2, 2008)

Tip noted and logged for future reference ;D . I've never seen those grubscrews before (quite expensive compared to the stainless ones I usually buy!!) http://www.stagonset.co.uk/fastener...05&prm_grp=A2_ScrewBolt_GrubFlat_M4&summit=M4 

Definitely never thought of making my own soft tips! (got that glitch in the matrix feeling I've seen the tip somewhere before though  8) ???  The brain is not what it used to be!! )

Thank you John 

Ralph.


----------



## Bogstandard (May 2, 2008)

Ralph,

For small stainless stuff, try here

http://microscrews.easywebstore.co.uk/

Sort by price, low to high

John


----------



## Divided He ad (May 2, 2008)

Thank you John, viewed, price compared and favourited  ;D 


Ralph.


----------



## Circlip (May 2, 2008)

Those brass tipped grub screws are what I made for the Works plastic cutting saw where I worked John. Never seen 'em before, could have claimed a fiver at the time I made them, didn't have the tackle to do it at work, another home free bee (B**tards)  Regards Ian.


----------



## Lew Hartswick (May 2, 2008)

I knew they existed but when I tried to buy some for a fixture I was building couldn't find anyone in the 
city that had them so made a bunch. It was pretty easy, drilled and taped a short peice of round 
stock in the lathe to the depth of the screw and then on through with a clearance for the allen wrench to 
fit the screw. Screw the set screw in "backwards" and drill an appropiate hole in the "front" of the screw
and press in a bit of brazing rod. The top of the screw "bottoms out" on the hole and dosent turn while 
doing the drilling but the through hole lets you remove it with the allen wrench when done. 
 Alot easier done than describing it.  
  ...lew...


----------



## dparker (May 2, 2008)

Hello All: Another way to help with this problem is to use a bit of lead. I had some lead round stock (sold like solder) from the sports shop sold for fishing line weights, it was left over from fine tuning the son's pinewood derby racer weight in Cub Scouts. I cut a piece of this to fit in the bottom of the hole and put in the set screw and tightened. It formed into place and worked for what I needed but would be a little soft for a high torque situation I think. I have also used small pieces of lead cut from wheel balance weights for vehicle wheels.
Guy Lautard, in one of the Bedside Readers mentions drilling the end of the screws and inserting a piece of brass brazing rod and slightly rounding the end. This must have been a good idea as it has been mentioned by Lew also.
don


----------

