Valve grind 5

[woophuh]

what I dont get is how he knows hes drilling a straight line? and not into the head

[pishta1968]

The pilot on the end of the bit guides the drill into the guide, the bit is designed not to cut on the sides, only at the cutting edge right above the bit guide. The hole (guide) he is drilling is not blind so he can drill right through.

[thinkpad411]

@pishta1968 Yes it doesn't cut, it simply "piles up" material to bring the bore diameter back to spec. Much like a knurling tool for a metal lathe, it doesn't actually remove material, just creates a pattern by "piling" it up.

[woophuh]

what I dont get is how he knows he is drilling a straight line?

[vaptube]

GREAT VIDEO!!!

but one thing i dont get is"how can you create less surface area inside the valave guide?" ...... physicaly possible????

[pishta1968]

That is what a knurl does. To put it plainly, it forces a tapered screw into the reamed guide. The screw (knurl) threads force themselves into the guide without cutting it so the metal had no where to go but up into the minor diameter of the screw (knurl) thread. so you now have effectively reduced the ID of the guide even smaller than the valve stem. Now you ream (a cutting action) to the recommended od of the valve adding the expansion and oiling tolerance, .001-.004. BUT WITH LESS DURABILITY

[thedonofbradford]

in england we call debrie swarf, and what you call knurling we call milling, a knurl is what you would find on a tool so u dont loose grip. u use imperial measurements thats well complicated and, in england we call it a tap wrench never heard of hand arbor. and u forgot to mention that the tool must be square otherwise valve wont sit straight

[cosast54]

So what! he uses different terms whats your point?