drilling m12-m14 on struts

[martinws]

I was drilling out my rear struts to fit the larger bolts today an managed ok with the struts but the hubs seemed really hard steel and the drill didn't like it much so I stopped. Anybody else done this with a better outcome?

[Sleeper_Avant]

why would you want to drill out your rear shocks and hubs to just fit bigger bolts out of curiosity?

[martinws]

The m12 3b bolts are NLA and I had already bought 8 new m14s with washers and nuts. It has been done before but can't find if they had problems or I just bought scrap drill bit.

[Sleeper_Avant]

ah ok i see,

the hubs are cast and not that hard mate, id guess at **** drill bits

use the drill on a low speed with plenty oil

im always drilling out snapped bolts that the mogoloids at work **** up, quality bits always are a must

[andy10v]

Are you using decent/fresh drill bits?

I have decent/cheap drill bits, and its night and day, I use the cheap ones for abusing.

I got a fancy set of bosch ones for making a set of railings, they would fly through the plate in about 15s v a couple of minutes for cheap drills (which were also wrecked after a couple of plates)

Cutting fluid makes a world of difference, also right speed/pressure, dont smoke it.

[Sleeper_Avant]

think of it like a clutch, set off on the rev limmiter and something is gonna smoke like **** and not work propperly lol

[Error404]

Be careful drilling out the hubs, the M14 versions have more meat in the hole bosses. You could weaken them taking them out to M14.
I agree with the above though. Good quality drill bits and the right drill speed are essential

[martinws]

It was a brand new drill bit but was only a few quid so obviously it was scrap. I'm gonna get a good one and hope for the best. Iv only got 4 holes to bore out.

[bambridge]

Its easy for me to say, but take them to a machine shop, so they can bolt them down on a milling machine and drill thro the existing holes.

First thing that happens when trying to enlarge a hole is the drill will vibrate and either grab/snap or blunt the drill, using a millling machine will stop that and also, slow the speed down otherwise your will burn the drill out

[europeanme]

Its easy for me to say, but take them to a machine shop, so they can bolt them down on a milling machine and drill thro the existing holes.

First thing that happens when trying to enlarge a hole is the drill will vibrate and either grab/snap or blunt the drill, using a millling machine will stop that and also, slow the speed down otherwise your will burn the drill out

a machine will be less likely to drill on the pi55...or 'grab' and do some real damage....

[Tonks4x4]

Or have a vice like grip and take it steady. I use 12.5, 13, 13.5 then 14 to drill the hubs. And have several trips back and forth to the bench grinder to keep sharpening them

[martinws]

That was my plan B after I looked at the price of a half decent drill bit. What would you expect to pay for the 4 holes?

[bambridge]

to bolt them onto a table and drill thro 30/45 mins max £15/£25

[martinws]

I think that will be my best bet. I was looking at a mill and lathe on ebay the other day but missed the final bid by about 5mins because i was driving and forgot.
cheers.