Most common drill bits and tap/die sizes used for restos?

[highwayzero]

Hey Folks!

Getting started tearing apart a rusty zwitter...what are the most common size drill bits and tap/die sizes does everybody recommend to have on hand to drill out broken bolts and clean up rusty threads?

Part 2...what's the morr conversions for say a 10mm wrench size = ?? thread size, 14mm wrench = ?? thread? Kind of a noob question!

I've worked on hot rods the last 20 years or so and I'm trying to get accustomed and stocked up on metric...

Thanks!

[Hawker]

Plus Gas! Buy tins of Plus Gas and soak every fastener in it.

Best of luck!

[finster]

^^ and heat helps too
re part 2 - note that early vw bolts can have a larger than standard head for a given thread dia eg 14mm head m8 instead of the standard 13mm
have a look at these topic threads

https://www.thesamba.com/vw/forum/viewtopic.php?t=273479&highlight=thread+sizes
https://www.thesamba.com/vw/forum/viewtopic.php?t=530301&highlight=thread+sizes
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nothing lasts, nothing is finished, and nothing is perfect...

[Lind]

Get a parts list. Anyone who is restoring a car will make their life so much easier by getting a parts list, and using it. Hardware is listed in very specific detail.
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Wanted:
Idaho VW license plate frames or other dealership items.
VWoA literature and early dealership or distributor literature/pictures/information
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[61SNRF]

Most common body/chassis bolts/nuts are:

M6 x 1.0, usually 10mm hex but also come round head philips

M8 x 1.25, either 13 or 14mm hex but also countersunk tapered head for door hinges.

M10 x 1.5, usually 17mm hex but also use 15mm hex head bolts for rear axle bearing caps and 15mm hex nuts on front transmission mounts.

M12 x 1.5, usually 19mm hex head bolts such as rear spring plate/axle tube bolts.

This topic will get you a few oddballs:
https://www.thesamba.com/vw/forum/viewtopic.php?t=...mp;start=0

As for extracting broken bolts that's an art form in itself but in general these are my favored type which have the recommended drill size stamped on them:

For larger fasteners of course start with a smaller pilot hole and work up to the recommended size last.

For any sort of captive nut plates in the body or chassis you want to preserve as much of the original threads as possible. Avoid the use of a plain tap or die which removes too much metal and instead use a thread restoring/chaser like this:

Not certain if the early manuals contain the info but the later Bentley series of factory reprints have an index of fastener size, length, pitch and hardness. If you're tearing into the car having a good manual is a recommended prerequisite.
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-Bruce

An ounce of prevention is worth a pound of cure.

[highwayzero]

You guys are awesome...thanks!

[djfordmanjack]

Many of the hex head sizes will accept imperial ( inch) wrenches ok

8mm=5/16
(10mm=3/8")
(13mm=1/2")
14mm= 9/16
17mm=11/16
19mm=3/4

I am working the other way around. we are all metric here and I have been building Rods and US iron for 25 yrs. The dimensions in brackets are not well suitable, but might just work. these 2 US spanners will be slightly smaller than metric, so in some cases work GREAT on worn and mangled bolts. all other sizes you can easily use your spanners, depending on quality and accuracy of your tools.
as for chasing threads, old high densile strength bolts with a few slant cut grooves work great for that.
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