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Imperial or Metric Fasteners?


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My Vitesse Convertible project is progressing with most of the rear tub stripped down. Lots of seized rusty bolts & nuts though wherever exposed to the exterior. I assume that all the factory fitted fasteners were imperial specification? I'm a bit surprised how many metric fasteners have been fitted, presumably from previous bodywork. I am intending to replace them all with imperial and possibly stainless steel versions to help in the battle against rust.

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28 minutes ago, t-stag said:

My Vitesse Convertible project is progressing with most of the rear tub stripped down. Lots of seized rusty bolts & nuts though wherever exposed to the exterior. I assume that all the factory fitted fasteners were imperial specification? I'm a bit surprised how many metric fasteners have been fitted, presumably from previous bodywork. I am intending to replace them all with imperial and possibly stainless steel versions to help in the battle against rust.

Helicoil's work well - worth having them handy.

Rivnuts for thinner areas = UNF are available

Weld the hole and re-tap - emergency work

Stainless fasteners - becareful. Do not use in high stress areas (suspension etc)

If you go metric, consider painting the head of the fastener red so that you know what is there.

 

Roger

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Don't mention metric and imperial nuts/bolts. When the garage fitted my leaf spring they managed to force a metric nut onto an imperial bolt. Yes, it stripped when I had to redo their incompetent work.

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Thanks all. Will check out helicoils and rivnuts. Depending on access, my angle grinder/cutter has solved a few issues.

Previous garage work has been variable with some obvious bodges. 

Drilling out fasteners is hard work as the drill bits get blunt so fast. Is there a special tip version for this?

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4 minutes ago, t-stag said:

Drilling out fasteners is hard work as the drill bits get blunt so fast. Is there a special tip version for this?

Buy good drill bits. I used to buy cheapies and they wore out in minutes; go for good branded versions and they'll last a lot longer. 

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35 minutes ago, t-stag said:

 

Drilling out fasteners is hard work as the drill bits get blunt so fast. Is there a special tip version for this?

I use cobalt drills a lot harder.

Regards

Paul

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Copper slip the bolts/threads to stop seizing. Just remember the lube affect will allow the bolt to go tighter and if your a bit heavy handed snap a head off a small bolt!

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1 hour ago, Mathew said:

Copper slip the bolts/threads to stop seizing. Just remember the lube affect will allow the bolt to go tighter and if your a bit heavy handed snap a head off a small bolt!

It's only the last quarter-turn that does that...

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Have ordered a set of cobalt drill bits, will see how much better they are.

All the fasteners should have been UNF (fine) or UNC (coarse) imperial and zinc plated.

Stainless steel is recommended alternative but more expensive.

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I got a set of standard drill bits last year not realising at the time exactly what they were then got some of the same size cobalt ones. The cobalt ones were great, but the standard ones only did a few holes before they shattered?

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37 minutes ago, Badwolf said:

I got a set of standard drill bits last year not realising at the time exactly what they were then got some of the same size cobalt ones. The cobalt ones were great, but the standard ones only did a few holes before they shattered?

I used to buy drill bits from a display stand in my local Autofactors and they lasted no time at all; in fact many of them broke under any kind of pressure. I even had one wind up like a corkscrew. I asked the in-laws what they used in their professional machinery and they gave me a few spares which have lasted forever. I never asked what they would have cost originally from their suppliers.

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Agree!   I have a Bosch electric screwdriver but use it as much for drilling small holes, up to about 8mm.   The drills that came with it have a hexagon shaft, so no need for a chuck, but eventually they wore out.  I searched for and bought a new set from Amazon - rubbish, they weren't sharp when new!

But then I found a set of OE Bosch drills.  A lot more expensive but sharp!

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Many of my drills, come from my days "on the tools", being imperial and are still in good order despite having been reground regularly, later additions are of a variable quality. The Metric ones are the worst offenders, my Swedish ones are best. Small ones I often regard as "use once, throw away". The taper shank ones, I use in the Lathe stand up well, some must be getting on for 80 Years old as they where not new when I aquired them. 

 

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You regrind your bigger drills, PeteH?     It is supposed to be a useful skill, and relatively simple to do, if you have grinding wheel, but I have reduced more than one from a bit blunt to ruined.    Is there a secret?

JOhn

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On 05/05/2021 at 08:31, t-stag said:

I am intending to replace them all with imperial and possibly stainless steel

If you do use stainless you need A4 spec. A2 snap like carrots. Also buy from a reputable supplier, rubbish fixings abound are out there and can be very dangerous. 

Iain

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Just now, JohnD said:

Do you resharpen your bigger drills, PeteH?     It is supposed to be a useful skill, and relatively simple to do, if you have grinding wheel, but I have reduced more than one from a bit blunt to ruined.    Is there a secret?

JOhn

In a word, Practice. We all did "time" in what was refered to as the "grindery" as aprentices, taught to sharpen all sorts of tools including drills, Lathe tools, Milling cutters. A good basis for later life. I can still do the bigger ones, but age(ing) eyesight, has curbed the ability to be accurate with the smaller ones. So now I "cheat" having bought a drill sharpener a few years ago. One "secret" is to have the Stone properly "dressed", if you are going to do it by eye. I still have my drill gauge, we all made them in "training school", which gives the correct angle.

Pete

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drill gauge    the drill is now only 1" long and the gauge says  start again  

I have box fulls of redundant drills  also have a shaperner non of wich do the right angles 

theres a old knack in getting the angle the twist of the  wrist and a flip to not end up with a land as big as the hole  !!!!

my last set of black Dormer have out lasted many old favourites but i didnt pay the current prices    Ouch !!

Dormer A190 Series Metric High Speed Steel Drill Sets

Pete

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Wish I had the expertise to sharpen drills luckily I can buy packs of six of one size so those I break frequently can be easily replaced interestingly I brought a set of imperial drills a couple of years ago and they seem to stay sharper than the run of the mill metrics but the break shatter easily. The imperials also go up in 1/64 increments

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Bought a set of Heller cobalt drill bits from Toolstation 94153 for £38-32.

Still hard work, but they drilled the bolt heads much better. Used a hole punch first to mark the centre, then worked up in order of sizes. Laborious and had to fix a ring spanner on to the head to stop it rotating.

The rear overiders and all 3 valances are now off. Progress!

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Got some drill bits and taps from the london tap company as recommended on this site. Drilled stainless like butter all day long with them. Would recommend them.

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