Blind Tap

[djw2k3]

What would be an easily achieveable minumum plate thickness to create an M8 blind tapped hole?

This is purely for holding down some plastic and non structural counter sunk screws.

Would 10mm plate be too thin for this to be achieved without great difficulty?

DW

 

[BillPSU]

I would try to avoid using tapped blind holes if possible. Through holes would be preferred. I would rather use a weld-on stud instead of blind tapping the part. Broken taps will be a headache. A bent or broken stud can be fixed relatively easily compared to a broken tap.

Do the parts need to be removable or is permanent mounting an option. To attach metal serial number plates and other small items I have used metal tacks from Amtack Fasteners. Quick and easy and no drilling.

http://www.amtakfasteners.com/

 

[MintJulep]

without actually looking up the dimensions.....

You don't want the hole to break through, right? Take away 2 mm to be safe.

Drill bits are pointy. Take away say 3 mm that you can't tap.

Countersunk? Another 3 mm.

That leaves you with 2 mm of useable hole depth for tapping.

M8 is 1.5 pitch. Leaves you with a bit over 1 thread. Not too much.

So, I would hazard to guess that 10 mm plate is too thin.

 

[CorBlimeyLimey]

Using the SW Hole Wizard for M8 Bottoming Tap, & changing the 2xDia to 1xDia, gives approx 8mm drill depth, so 10mm is achievable. However I agree with the others, it would be much better to go with a through hole or alternate fastener if possible. Also depends on how many holes are required & whether it is being done by hand or machine.

Your best bet would be to use a self tapping or thread forming screw?

from (the City of) Barrie, Ontario.

I tried sniffing Coke once, but the ice cubes got stuck in my nose

 

[yates]

What's the plate made of, plastic, aluminium, steel ? In steel 1.5D is the normal minimum for blind taps. I would leave more in ally or other soft metals.

 

[djw2k3]

Hi all,

Pretty much confirmed my thoughts.

Yates, the plate is structural steel.

I would prefer to drill through also but the plate makes up a welded structure enclosing a sealed empty void (imagine a hollow steel cube). By drilling through, this would perhaps allow corrosion to occur inside the unpainted void if for some reason a fastener (that would normally plug the hole) was accidently left out.

DW