Does anyone know what the correct thread diameter and pitch is for the spare tire T-Bolt on the early (70-73) Z cars?

I have the plate, but not the T-bolt, and have not been able to identify the bolt size needed.

It doesn't seem to match any bolts, or taps that I have on hand.

I don't know the diameter or pitch, but I do have at least one (maybe two) spare T-bolts. Shoot me a PM if you're interested.

I tired to get a bolt that same pitch from the local True-value. I have to say, I did not understand what they told my son, but it was basically that it is a VERY unique pitch and they had no source for it. Something about a "square pitch" thread.

... Something about a "square pitch" thread.

That is what I was afraid was the case. I have seen other hold down devices on cars, and other things that used a square thread, like is on an Acme screw, instead of the triangular threads that are used on fasteners.

That is what they said...and Acme screw...thanks for the jog...

A while back I bought a cheap wood lathe at Harbor Freight just to play around with. While at the store I noticed some metal lathes. While I've never used one they appear to be capable of cutting any kind of thread you need. Here's an example of the Acme thread:

http://en.wikipedia.org/wiki/Acme_thread_form

Obviously getting a spare from Arne is the way to go ... even if you could find the proper thread you've have a hard time with the handle part. Here's a shot I just took of mine.

Ummm....y'all have heard about eBay, right? :laugh:

http://cgi.ebay.com/Datsun-240z-260z-280z-Spare-Tire-Hold-Down_W0QQitemZ130194697270QQihZ003QQcategoryZ33746QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

http://cgi.ebay.com/Datsun-280Z-Spare-tire-Screw-Down_W0QQitemZ160074256168QQihZ006QQcategoryZ10076QQrdZ1QQssPageNameZWD1VQQtrksidZp1638.m118.l1247QQcmdZViewItem

http://cgi.ebay.com/Datsun-280Z-Spare-tire-Screw-Down_W0QQitemZ160074256195QQihZ006QQcategoryZ10076QQrdZ1QQssPageNameZWD1VQQtrksidZp1638.m118.l1247QQcmdZViewItem

Ummm....y'all have heard about eBay, right? :laugh:

Yup, sure have. And I consider eBay to be my very last resort, for either buying or selling.

As a seller, the fees, rules and hassles with deadbeat bidders are seldom worth it. As a buyer, there are almost never any good buys on eBay anymore. You have to pay premium prices to win an item by outbidding people who: a.) have no clue what a reasonable price is; b.) get carried away in the feeding frenzy and over bid; c.) are shills; d.) bid high for entertainment but have no plans to pay if they win; e.) are willing to pay way more than market value to win; or f.) are just plain stupid. And then if you do bid enough to win, often the item is nowhere nearly as nice as described.

No, eBay is a last resort. I'll sell my stuff for less than eBay prices, I won't pay eBay fees, and the buyer gets an honest part and a fair price.

I agree

Less face it, the part in discussion is not some rare hard to find piece. Why go looking around for a make-do bolt with an obscure square thread or even begin to think about machining one, when you could easily find it on eBay, craigslist, classiczcars.com classifieds or one of its members(Arne for one). Heck, the dealer probably still has it.

I think I've got an extra one in my parts car. I'll give it to you. What's your address, or send it privately.

The reason I was looking for one was to use as a hold down for the spare tire cover. We deleted the spare tire and that area now holds the sub woofer for the stereo.

We made a 3/4" MFD top and it is held in place by the spare tire hold down. We cut the top off of the hold down screw and welded a large machine head allen bolt to the top, countersunk the MFD top and it all fits tight and the head is below the surface of the MFD. If we need to get in there for any reason, one bolt and it is off.