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Suspension brackets holes/bolt play
ZEN - 15/1/11 at 09:53 PM

Hi there!
I'm in the process of making my suspension brackets. I went for 1/2" bolts as my GAZ coil overs have 1/2" bushes. The brackets are now drilled to 12.5mm and are too small for the 1/2" bolts i have. Tried to drill a bracket to 13mm and it seams a bit too much of play with 1/2" bolts.
Should i go for a 12.8mm drill or the 13mm will be OK?

Ben_Copeland - 15/1/11 at 10:02 PM

you can always tack the 1/2" washers on the outside of the brackets to remove that play

jacko - 15/1/11 at 10:06 PM

Get a 1/2 drill bit why use metric drills ?

ZEN - 15/1/11 at 10:14 PM

quote:
Originally posted by jacko
Get a 1/2 drill bit why use metric drills ?


Good idea. If I can find one locally.

austin man - 15/1/11 at 10:23 PM

13mm is too big the metric conversion is 2.54 to the inch therefore 12.8 is the closest if using metric giving 2.6cm if multiplies by 2

indykid - 15/1/11 at 11:04 PM

quote:
Originally posted by austin man
13mm is too big the metric conversion is 2.54 to the inch therefore 12.8 is the closest if using metric giving 2.6cm if multiplies by 2

erm...12.7's 1/2 of 25.4 which is 1/2" exactly

and 2x12.8 is 25.6mm

RazMan - 15/1/11 at 11:56 PM

I bought a 1/2" reamer for that job - £3 on eBay at the time as I recall

kb58 - 16/1/11 at 06:57 AM

quote:
Originally posted by RazMan
I bought a 1/2" reamer for that job...

This^. If you don't use a reamer on suspension bolt holes, drop your man-card off at the door on the way out! There's no excuse to have sloppy suspension pivots for all the work put into a chassis.

mogman1969 - 17/1/11 at 05:42 AM

quote:
Originally posted by kb58
quote:
Originally posted by RazMan
I bought a 1/2" reamer for that job...

This^. If you don't use a reamer on suspension bolt holes, drop your man-card off at the door on the way out! There's no excuse to have sloppy suspension pivots for all the work put into a chassis.







pmfpl !!!!!!!!!!!

britishtrident - 17/1/11 at 08:07 AM

A lot depends if you are using bolts or set screws.

ZEN - 17/1/11 at 05:43 PM

Excuse my ignorance. But what is the difference between bolts and set screws???

avagolen - 17/1/11 at 06:42 PM

Set screws are threaded all the way up to the bolt head.

Ideally, you want to have no thread in the holes.
It should finish 'within the washer'.
This is because the thread will be slightly smaller in diameter than the shank of the bolt - giving room for potential movement.

Difficult to achieve with standard bolts, but careful purchase and the cutting off of excessive thread can accomplish this result - or expensive specific bolt ordering.

HTH

Len.

ZEN - 17/1/11 at 10:13 PM

Thanks for the explanation. I have 1/2" UNF bolts with the shank just to the measure of the brackets. I did my homework on suspension nuts and bolts

mogman1969 - 18/1/11 at 02:43 PM

set screws a nono in suspention , last thing you need is the head of the bolts shearing off .......mind you , it would take a serious amount of force

phelpsa - 18/1/11 at 04:27 PM

You wont get play if you bolts are done up tight enough. It should be friction between the bracket and the crush tube that locates it, not the bolt.

Still not ideal to have slop but not a huge issue.

[Edited on 18-1-11 by phelpsa]

ZEN - 18/1/11 at 06:03 PM

Thanks for the advices. I have ordered a 1/2" drill bit. Hope i get it soon.

Strontium Dog - 18/1/11 at 10:38 PM

I have literally hundreds of drill bits. They are all different sizes to each other even though they might say they are the same size (except for my letter drills). I find it best to select a bit using verniers or digital calipers and then drill a test hole and measure that to see what size hole the bit actually drills