Board logo

Best way to rid threads of powdercoat
james h - 31/5/08 at 05:10 PM

The threads for the 8 (four each side) holes which attach the hubs to the uprights have (i think) become blocked by the powdercoat.

I have tried some M10 bolts but they are refusing to go in past the first thread, and I dont want to force them, unless its necessary.

Rear nearside upright
Rear nearside upright

M10 is the right size bolt, isn't it?

Thanks

James

iiyama - 31/5/08 at 05:22 PM

Sure youve got the right size thread? Standard M10 is 1.5mm, although there is metric fine, (1.25mm) and metric course, (1.75).

If your sure its a standard thread then run a tap into the hole to clear the threads.

James - 31/5/08 at 05:22 PM

Mmmm, well I don't know the 'M' number it equates to but the bolts need a 13mm socket!

I'd use a tap to clear it out.

Cheers,
James

EDIT: Oh, beaten to it!

[Edited on 31/5/08 by James]

iiyama - 31/5/08 at 05:23 PM

Socket size will be the same for all!!

James - 31/5/08 at 05:27 PM

quote:
Originally posted by iiyama
Socket size will be the same for all!!


Out of interest, how does thread size relate to socket size? Presumably there's a scale somewhere?

Not important, just one of those things you wonder!

Cheers
James

Hellfire - 31/5/08 at 05:28 PM

Assuming you don't have a tap to hand, take a longish M10 bolt and using a hacksaw, cut a groove down the length of the bolt. Screw the bolt in and it should clean the threads out.

Phil

rusty nuts - 31/5/08 at 05:42 PM

Or file a flat on the lengthof the bolt. Easy way to check thread size is to measure the diameter of the threaded section , invest in a thread gauge and use to check the pitch . Zues chart is useful as well

indykid - 31/5/08 at 07:24 PM

quote:
Originally posted by James
Mmmm, well I don't know the 'M' number it equates to but the bolts need a 13mm socket!

I'd use a tap to clear it out.

Cheers,
James

EDIT: Oh, beaten to it!

[Edited on 31/5/08 by James]


as a general rule of thumb, and i mean really general..........

7mm AF = M4
8mm AF = M5
10mm AF = M6
13mm AF = M8
17mm AF = M10
19mm AF = M12
22mm AF = M14?

you then also get all sorts of custom sizes, usually for suspension bolts and such like. the M number determines the outer diameter and the thread form. anything else such as head size, assuming it's hex, or thread pitch can be made to suit the application.

in some odd circumstances you also get M7 or M9. the drive plate to torque convertor bolts on a supra are M9 with an 11mm hex head, bucking the trend of anything i mentioned above, hence it being a general rule of thumb.

hth
tom

StevenB - 31/5/08 at 09:42 PM

James,

Im using M10 x 35 Socket Caps (12.9).
Originally used hex bolts but scored the
paint off the hubs with the jaws of the
spanner as its a bit tight against the main body of the hub.

A few of my parts arrived with the first thread or so slightly blocked with powder.
Seat belt fixing points mostly (7/16 UNF)

I used a needle file to pick at the lead in thread and / or just took it slow when starting
with the odd reverse out to clear the powder as it chips off.

Cheers

Steve

MikeRJ - 1/6/08 at 12:43 AM

quote:
Originally posted by Hellfire
Assuming you don't have a tap to hand, take a longish M10 bolt and using a hacksaw, cut a groove down the length of the bolt. Screw the bolt in and it should clean the threads out.

Phil


This works a treat, done it many times. If you finish the cutting edges with a file and taper down the threads leading up the the cutting edge you can make it work well enough to actually cut threads in softer materials such as aluminium alloy.