how do you measure a self tapping screw

[ShipsWoofy]

I missed the jumble and need to replenish my ss screw box, which I brought home especially to take with me.

Usually I go through A2A4's bins and pick sizes on sight. I would like to put in a mail order and it is quite difficult to work out from his pages which screws I need to order. This may seem dumb, but as I said, I usually choose on sight.

Length is obvious on a pan head, from the point to the underside of the head, but on a countersunk is it to the top as the screw buries itself.

Then there is width, do you measure to the inner on a self tapper or to the outer extreme of the thread?

Is there anyone else other than A2A4, I can't seem to find any stubby pan head screws on his site..

Sorry if this is a really daft question, it is something I had never thought of before I looked at the website.

 

[VicS]

From the flat top of a countersunk screw.

Diameter is the over the thread diameter. But the British system is by gauge number like wood screws I think you will find

Seascrew is another source, and they list them by gauge number!

Woodscrew sizes

Drill sizes for self tappers

 

[2Tizwoz]

Like this

 

[ShipsWoofy]

cheers both..

I am finding it rather difficult to buy on line, they are definitely an item that I like to see what I am picking up. Even with the screws in front of me and my vernier it is taking ages per screw.

If he had taken a photo of each screw along side a pound coin for example I think that might help.

I will have a look to seascrew to see if that is any easier. I think one of the problems, it seems some things are standard, so he gives away limited information, but it is that info that I would like to see to know I am buying the right thing.

edit>> hmm, it seems you need microsoft explorer to shop at seascrew.. what a ridiculous way to set up an on line shop.

 

[VicS]

[ QUOTE ]
hmm, it seems you need microsoft explorer to shop at seascrew

[/ QUOTE ] I have only shopped at Seascrew once and i definitely did not use Internet explorer.



It was long drive though but at least I could look at what I was buying.

 

[philip_stevens]

Although A2, I have used these for quite a few years on the boat.
Screwfix Direct

13743
Stainless Steel Self Tappers Pack 500Pcs

500 Pieces. Csk and Pan A2 grade Stainless Steel. 4-8ga, 1/2 - 1¼".

 

[philip_stevens]

Doesn't appear to work properly with either Safari or Firefox.

Perhaps they should get up-to-date and get it working with all browsers.

 

[sailorman]

Any wood screw or s.tapper
measure the head in 1/16 " double answer & take off 2 = gauge

5/16 x 2 = 10 - 2 =8 gauge

 

[savageseadog]

What many people don't realise is just how many thread and tip forms there are for self tappers. It is often a case of just looking.

 

[whipper_snapper]

[ QUOTE ]
Doesn't appear to work properly with either Safari or Firefox.

Perhaps they should get up-to-date and get it working with all browsers.

[/ QUOTE ]

I gave up with seascrew for this reason. I asked them why and thy replied

We are aware it doesn’t like firefox, the site should have warned you that you may have trouble At this moment in time it is only set for Windows IE the cost of setting for both would £100 to £500 a month.


Which makes absolutely no sense to me.

 

[Cliveshep]

Like Phillip Stevens says, try Screwfix.com, currently very cheap indeed on all stainless steel woodscrews (listed as external quality) and also s/s self/tapping screws.

 

[maxi77]

Certainly I have found Seascrew service excellent as is Screwfix if they supply what you want. Strangely the larger B&Qs are now stocking a limited range of stainless self tappers in the smaller sizes

 

[Sailfree]

[ QUOTE ]
Certainly I have found Seascrew service excellent as is Screwfix if they supply what you want. Strangely the larger B&Qs are now stocking a limited range of stainless self tappers in the smaller sizes

[/ QUOTE ]

Screwfix & B & Q (and before their demise Trade Depot) have the same owner and I assume the same buying dept. I have mistakenly taken goods back to B & Q & got a refund against the barcode and later discovered that I bought item from a cheaper source - genuine mistake!!

 

[maxi77]

I was aware they were both from the same stable but didn't realise they were quite as close as that

 

[ShipsWoofy]

ah, like the solid brass screws with caps (in the same pack) I bought from B&Q to screw on the bath panel at home..

A nice rust streak now from each washer... I don't trust anything from that outfit.

 

[ShipsWoofy]

thank you all, using the conversion chart on the seascrew site I spent the afternoon measuring and labelling my screw box, each tray is now marked so I can write a list on the boat as I take screws out (yeah like I am that well behaved) though I resisted adding a minimum qty for each tray.

Following on from refueller, it is not just the pitch of screws, using a digital vernier I saw quite a range of lengths and widths across each size, No 8 seems to vary the most (in my trays anyway). Whitworth would have been rolling in his 1,828.8 mm grave.

It is a job worth doing and should make life easier next time I am at the jumble trying to remember exactly what I need. I have placed the order and the total just frightened me, I should extend my household all risks, just to cover the 'bit' boxes /forums/images/graemlins/grin.gif

 

[maxi77]

I think on of the problems these days with screw sizes is that the old guage numbers may have metric equivalents but they are not exact equivalents.

 

[philip_stevens]

My son is a website designer, and cannot understand their answer!!

He designs on a Mac and tests on both Mac and PC, and all browsers.