General Fastener sizes - how to decode parts list?

[Mferg]

Hello,

I am trying to figure out how to determine fastener sizes for nuts/bolts etc. listed in the spare parts catalog. For example, I am using the 3rd edition of the spare parts catalog for 110.140 and 110.144. In Subgroup 10, part number 7 is listed as a "screw with captive washer" and is listed as part number 1/38015/11. Is there another reference document that translates that part number into an actual fastener size or does anyone know how to determine that information?

Mark

 

[The Panda Nut]

In short I dont know. I usually just look. With Fiat there are only a very few sizes used on 95% of things. I have seen charts on eBay that give some useful information,

 

[Toshi 975]

A lot of the original fasteners were indeed bolts or screws that included a captive spring washer located in an undercut beneath the hexagon head. As far as I am aware there is no fastener manufacturer that produces such a thing. If I have had to replace such bolts I have used suitable high tensile bolts with separate rectangular section spring washers. Those spring washers tend to be stronger and spread the load better than square section ones.

 

[grubscrew]

A lot of those captive washers on these bolts are known as shoulder bolts, at there is a small section of bolt under the head as it were which is smooth, but of a slightly smaller diameter than the trough of the thread further down, this smaller diameter is how the washer stops sliding off the thread.

If you are able and have access to a lathe and want to go this far, use a standard bolt, ( with thread along its entire shank), and turn down enough metal the thickness of said washer. By opening up a spring washer ever so slightly slide it down the shank. Then close washer back up with pliers/ vice.