osugasman

OK. What is the deal with the German bolts. Help me out here. Very close to metric but with different thread pitch? Where can we source these (VW, Porsche only)? What are they called?

Do you need to buy special taps and dies or will the metric stuff work well enough? I'm guessing no...

Thanks, Brian

osugasman

OK. The only DIN tap/die sets I can find are 250-500 per. When people need to drill out a stripped bolt, do they just use a metric set and then a metric bolt and somehow remember that some bolts are metric and not DIN?

Akerlie

What bolts are you dealing with ?
I have only seen metric bolts on my 993.
There are some fine pitched bolts here and there but they are still metric (like the seat belt bolts)

911PERVY

They are all metric, sometimes the pitch is different than the standard for that metric size, ie; engine mount bolts are 1.5 industry standard for M12 is 1.75

osugasman

A couple of months ago, I removed a "metric" bolt and took it to the local hardware store to find they had no matches since it was a DIN bolt and not a metric bolt (different thread pitch). I was looking to upgrade old hardware and can't remember exactly where the bolt came from. When doing the belts, I purchased all new hex socket head bolts for the fan pulley at the same time because I was afraid of this. I have also removed the bolts in the seat track to get under the seat recently for a fire extinguisher bracket install and thought those were marked DIN as well (not metric) although metric allen wrenches are the correct removal wrenches.

It has to do with the pitch of the thread, not the head on the bolt. See item 12 in attachment.

osugasman

911PERVY: then what would you use to retap a thread? Is there any rhyme or reason so finding the bolts locally ahead of time could be arranged vs the ones that need to be ordered from a Porsche (Sunset) or VW place?

911PERVY

You could check on PET, most sizes are on there, but you need to keep your eyes open as there are a few curveballs on the 993, maybe a tap and die set in various pitches?

Ed Hughes

These are all metrics, as mentioned, there are fine and coarse pitches, as in SAE. Porsche did use some very specific sizes, heads, etc for the task being done. The bolt shown in your diagram is a metric, as noted.

I'd not expect the local hardware store to have a lot to offer you, save the basics. I use the Porsche part number, and order from the supplier of your choice, to get the right fastener. Some, you may find at a dedicated fastener supplier in your area.

I think I've had to chase threads on all of two fasteners in the many years of substantial projects on 911's. Done with metric taps.

PorscheDoc

Almost all of the bolts are standard metric pitch on the 993 and all other Porsches. Typical pitches used are:
m5x.8
m6x1.0
m8x1.25
m10x1.5
m12x1.5 or 1.75

This will cover 99% of the hardware on the car.

osugasman

Awesome, guys. Thanks again!!! Merry Christmas to all.

--Brian

IXLR8

Hi Brian,

Nothing could be easier.

Metric fasteners are listed by "thread diameter" - "thread pitch" - "fastener length", the latter depends on the DIN number of the fastener. When you see M6 x 30, it usually means a standard coarse pitch ie: M6-1.0 x 30

The DIN number tells you the type of fastener. For example, a DIN 931 is a partially threaded socket head cap screw whereas a DIN 933 is a fully threaded socket head cap screw.

This CHART shows metric threads with coarse (the most common), fine and extra fine thread pitch.

Fine threads would be found on our spark plugs, for example. M14 x 1.25.

American SAE threads are listed by diameter (1/4", 3/8", etc) or machine screw size (#4, #6, #8, #10) and Threads Per Inch (TPI - which is NOT a pitch, but a representation of pitch).

1/4-20 is a 1/4 inch thread with 20 threads per inch, 1/4-28 is a finer thread at 28 threads per inch. A machine screw would be a 4-40, 6-32, etc. The bolts on the MaxJax are a 5/8-11 (5/8" thread diameter with 11 threads per inch).

They're not special taps and dies, they are metric and available in different pitches.

TIP, never cheap out on a tap or die. Spend the coin for top quality.

weldcrane

for taps and dies go to mcmaster-carr .com they will have it all

IXLR8

I wish they would list what brands they carry. No mention of that at all.

I tend to stick with Dormer for general thread cutting and OSG for the tougher stuff.

osugasman

Man, Alex: you are a wealth of information. BTW: the compression anchors from WEJ-IT are complete garbage. I also wish the directions included a template for drilling the holes out. I could have made one, in hindsight, and I would currently have a functional lift. Well, what's a few more days....

Thanks and Merry Christmas!!

IXLR8

Its all in books...nothing new. The Machinery Handbook for example. An extremely worthwhile source of info....all 2500 or so pages of it.

I wouldn't go that far. Shops use anchors for their lifts. Its when you are not 100% familiar with something new and its the first time, you got to step back to take a closer look.

A few more days? Lucky you. It took me 5 months and 4 days from delivery to operational status.

Have a Merry Christmas and enjoy the food and drink.