Screw type and size?

[namwaldog]

I am doing some running repairs on our lawnmower.
There is a hard plastic belt guard under the cutting deck that screws onto bosses on a hard plastic rear baffle.
The belt guard takes some hammer and has to be removed to access the drive belt. It is held in place by a 13mm bolt at the top but the bottom of the guard, which takes most hammer, is held in place by two screws which I call self tappers.
I am going to order some replacement screws but in stainless and if possible wth a allen or torx head rather than the philips at present.

I am unsure if....
(a) the proper name is "self tappers". &..
(b) how to size them.

They look to be 15mm long from under the dome head and 5mm wide at the widest part of the thread.

Anyone help?



Thanks

Barry

 

[rb62]

Not sure on metric sizing,more use to 2inch no 8s! but I think this is the sort of thing your after.

https://rover.ebay.com/rover/1/710-...0001&campid=5338547443&icep_item=122686251699

 

[Sandancers]

By your measurements, 15mm long 5mm self tappers.

 

[namwaldog]

Thanks for the replies.
I have ordered a pack of 10 of these from Ebay.

Plus a pack of the slightly longer ones...No.10 x 3/4" (4.8x19mm) as I am considering making some sort of aluminium guard to try and protect the plastic.

Thanks again

Barry

 

[Manic]

I know you’ve ordered the self tapers but I’ve found these and the thread looks more like your sample.

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[autorouter]

Trilobular means not exactly round but kind of triangular with very rounded corners. Good for cutting their own thread, in plastic or metal.

 

[Geo]

Asks for help on specialist screws gets 2 or 3 very good to excellent leads (which i thought he woul;d never match) and then go's and buys bog standard tappers go figure

 

[namwaldog]

Thanks for your comments Geo .

If you look at the timeline....

3.17pm OP asking for help with identifying type and size of screws.

3.31pm & 3.36pm two helpful answers about type and sizing.

7.09pm OP is now on page three of "recent posts" so I ordered stainless "bog standard" self tappers and post what I have ordered as it shows the physical size 5mm wide thread by 16mm long is known as No10 x5/8" as it may help someone else.

7.53pm and 9.40pm two more very helpful answers, perhaps generated by my 7.09pm post, give more information on the type of screw I require.
I thanked those posters and left myself a note to order some of the trilobular screws in the morning.

Thanks again for your input.

 

[tribalbrit]

Stainless can be a right pain in the arse, not the best for keep putting in and out. IMO.