What is it Drill

[500e]

Any ideas what this form is for 0.138th
could be a No29 Guage

 

[brightspark]

made of cheese and its twisted

 

[Arclikeharrypotter]

LH cutting?

 

[Hood]

Have a few of these slow helix drills, all old, got from my Granddad so probably WW2 vintage. I think they are primarily for materials such as Brass/Bronze.

Edit, scrap the above info , just blown up the pic and I see the initial flute is reversed.

 

[Wildefalcon]

So cutting oil is drawn into the hole?

Looks like a manufacturing defect, but I can't see what could have gone wrong with manufacturing to achieve that!

 

[fizzy]

I have similar bits which I bought for drilling phosphor bronze.
I think the idea is to stop the tip binding and break up the swarf to avoid getting a huge helix of the stuff.
Of course I could be totally wrong - haven't used them for years!

 

[gordon stephenson]

Drill made from Chinesium, Specially designed to drill plasticine, (more than one drill may be required per hole.

 

[Screwdriver]

Drill made from Chinesium, Specially designed to drill plasticine, (more than one drill may be required per hole.

What they discovered is that you can make a helix from a flat bar of tin. If you insert them into a package labelled "drill bits", people will still buy them...

 

[slim_boy_fat]

@500e Have you tried drilling a hole with it?

 

[500e]

Yes

 

[500e]

Hood Fizzy
It appears to have left hand cut on tip & first 3\4mm & left hand flutes then becomes a standard drill.
The face feels & looks sharp, 60degree angle, it is a quality product not chinesum tried it in alloy does not cut at 1200rpm left or right rotation .
No one I have shown it to has seen another like it

 

[Hood]

Could it possibly be for drilling brittle material, the initial cutting forces being downwards to stop the surface chipping and the reversal of them to evacuate the chips?

 

[500e]

That could be an Idea but why left hand cut initaly

 

[Hood]

That could be an Idea but why left hand cut initaly

Is it left hand cut? Or just flute going that way?

 

[eLuSiVeMiTe]

Looks like it cuts rh spirals partly lh before returning to rh.

 

[Arclikeharrypotter]

Looks LH to me.

 

[mechman]

Why not try the drill bit on some material and see what happens.

 

[Bladevane]

It's for drilling holes particularly close to the equator. As we all know, bath water goes down the plug in opposite directions as you cross from northern to southern hemispheres. The same goes for helical drills.

 

[slim_boy_fat]

Why not try the drill bit on some material and see what happens.

tried it in alloy does not cut at 1200rpm left or right rotation .

 

[eLuSiVeMiTe]

Which would suggest it's blunt. Look at the pics. Cutting edge will cut clockwise.