Plus 2 - sill members set screws size

[jono]

I'm in the process of a sill member change on my project car.

The existing screws are dust - can someone please confirm the required size and length please so that I can place an order?

Cheers

Jon

[Bigbaldybloke]

Jono, which ones, the ones through the bottom edge of the sill or the ones that secure the seat belt mounting point?
I fitted stainless sill members so have actually used 6mm stainless bolts along the bottom of the sill, will go and measure them in the morning if it would be of help. Not original so depends how you feel on originality. Bolts for the seatbelt plates should be included in the kit with the sills, well, mine were but it was some years ago!

[jono]

Thanks BBB,

The ones along the bottom flange - the original ones are pan head slotted so intending to go for the same. Interestingly, and suprisingly, no large washers used on the originals and they are definately the factory sills but I'm going to use stainless penny washers inside and out probably 15mm dia and was thinking M5 set screws circa 20-25mm long?

Cheers

Jon

[Lotusian]

Your sill member kit should come with all necessary bolts and screws and the seatbelt mounting plates etc. Got mine from Spyder, and the screws which pass through the very bottom of the sills are button head socket cap type, M6 I think, with washers. Easier to tighten, paint and clean than hex heads.

[jono]

I'm a tad wad though as I've purchased so good used galv sills and there is no fitting kit.

I like the button heads (used these for the headlining clips last time) but I've gone all 'original' with this one so slotted stainless it must be.

So it looks like M6 is the way to go - any views on length - 20mm? (don't want to have to cut them if I can avoid it)

The obvious thing to do is offer up the new sills and then decide on screw length but I don't have the sills yet and I would like to have everything ordered and in place so that I can hit the ground running when they land

[mikealdren]

I too used M6 25mm stainless with penny washers, the originals were 1/4" UNF but they go through a clearance hole in the sill member so either is fine. I used hex head but, if I were doing again, I would probably use button head or even Allen cap which would be still more like the original slotted cap parts.

[Bigbaldybloke]

Just taken one out to check. I used M6 x 20mm hex head stainless bolts with a standard washer on the outside and penny washer on the inside. Had to bend a few of the inside penny washers as the bolts were quite near the floor. Must admit that having looked at them again I’m tempted to swap them out for the dome head Allen screws show in a previous comment. I’ve used them quite a bit elsewhere securing brackets etc to the body.

[mikealdren]

Sorry, should have checked, they are 20mm; my memory isn't what it was!

[Hawksfield]

Hi

My 1971 S130 Originally was hex head bolts not slots I replaced with socket head supplied by with Spyder cills
The choice is yours

[Andrewelan]

Just to add 2p worth, for fasteners I have lately used https://www.westfieldfasteners.co.uk/index.html who have the most immense range and terrific service. (no connection to the above, just a happy customer!)

[Bigbaldybloke]

Just an update, I checked mine out and found that the person who fitted them used a mix of stainless and mild steel plated washers. Removed them all to check and replace as necessary.
Important bit is that the bolts are various lengths not all the same. Majority on the right hand side were 20mm long and the left hand side were 25mm long. On both side the rear most ones were longer, being 1 1/4” long. This was due to the variation in thickness of the fibreglass, being hand laid up I guess this is to be expected. Also found that the some of the bolt heads were very close to where the sill curved out such that I had to grind flats on some of the washers on the outside to make them “D” shaped. Just need to paint them body colour now so they blend in.

[mikealdren]

Yes, I had to do some fibreglass repairs on mine around some of the holes which were no longer round and the faces were no longer flat. However I suspect they were probably not too perfect when new.