Nuts and Bolts

It has been said that if you own a 10mm, 13mm, 17mm and a 19mm wrench, you can take care of almost any nut or bolt on a Porsche.  While this is almost always true, there are a few nuts and bolts that require an 8mm or 12mm wrench.

We don’t want to get too basic here, but here are some specs on metric bolts.  The 10mm head is normally a 6mm x 1.0 bolt.  That means that the bolt is 6mm in diameter with one turn per millimeter on the thread.  The 13mm head is an 8mm diameter bolt, and the normal thread pitch is 1.25.  A 17mm head is a 10mm bolt, and the 19 is normally a 12mm bolt.  There are several thread pitch sizes for the 8mm, 10mm and 12mm diameter bolts, but most of the 6mm bolts are 1.0 thread pitch.  So when you see a bolt listed, it will be listed by diameter and thread pitch.

Bolts are then also listed by length, measured in millimeters.  The conversion is pretty simple – one inch equals about 25mm.  So a bolt that is a half inch long will be about 12mm, a quarter inch long bolt will be 6mm, and a 3/4 inch bolt will be 20mm, and so on.   So a bolt for the front cover on your 944 engine will be a 6×1.0 x 6mm – and you will use your 10mm socket on it.

IMG_2388Here at, we learned a long time ago to keep some extra hardware on hand.  As our projects grew, our inventory of new hardware also needed to grow.  Using an old rolling “tray rack” like you see in hospitals and cafeterias, we narrowed it to accommodate Harbor Freight parts boxes.  We can fit seventeen on a side, thirty-four total, and we have everything from bulbs to bolts to clamps and small parts – all labeled and cataloged so we can actually find what we need when we need it.  A pegboard was added on each side to allow hanging up things that we need often such as compression tester, air gauges, fuel pressure tester and various air tool attachments.  Note the board hanging on the side that helps us determine the proper bolt diameter and thread pitch. Very handy to have.

Having the hardware that you need on hand is much better than stopping your project and making the trek to the local hardware store to try to find that nut or bolt that you need.  Many have a “stash” of old nuts, bolts and washers in a coffee can or box, but let’s be realistic – you can rarely find exactly what you need after digging and digging in dirty, oily or rusty stuff.  And new is best.

imageWe source our hardware from BelMetric at  They are a supplier of metric fasteners and automotive specialty supplies, and you can order in quantities from only one to hundreds. Their fasteners are good quality and delivery is quick.  We order the hardware we need in bulk quantities, normally fifty or a hundred at a  time.

When you go to the site, you will see listings for all kinds of hardware.  Select a metric nut, let’s say an 8mm nut.  There are choices for course or fine thread, and eventually you get to the specifications for the nut itself.  For example, it may be:

  • Diameter: 8mm
  • Pitch: 1.25 Coarse thread
  • Height: 6.5mm
  • Wrench Size: 13mm
  • Material: Class 8 Steel
  • Finish: Yellow Zinc Plated

If you buy 100 of these for your stock, they are 11 cents each, $11.00.  Add a hundred yellow zinc flat washers for another eight bucks.  Inexpensive way to stock up on nice new hardware.  And it’s a good way to organize your spare parts.

Trips to the hardware store can get expensive.  We still have to do it from time to time, but this way you save both time AND money.  And the Harbor Freight boxes help with organization. And it’s a good way to organize your spare parts.


Author: Kevin Duffy, LLC, DeLand, FL

After retiring from a career in Law Enforcement, Kevin Duffy turned his attention to one of his passions, Porsche 944's and 924S's. He owns LLC in DeLand, FL, rescuing and restoring forgotten Porsches, bringing them back to a useful life. He is especially interested in the rare-but-beautiful 924S Special Edition. He can be found at Porsche Club events, including track days, tours and shows, as well as other car-focused events around the southeastern United States.

2 thoughts

  1. If you want to measure a bolt length in millimeters and don’t have a metric measuring stick, get out the wrenches. Short bolts can be measured by comparing the jaw opening to the bolt – if it measures on a 16mm wrench, then it is a 16mm bolt. (You can also use wrenches to measure the approximate diameter of your sway bars – a 27mm wrench fits with a little slack over the front sway bar, you can be assured that it is a 26.8mm bar. Handy when ordering new bushings.)

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