With this method of sharpening the drill, you can use two drills at the same time in one hole How to make a handmade drill bit: • How to make a handmade... Creativity with lathe: • Creativity with lathe
Oh, I see. Becasue of the continuous guiding of the Center Drill Combo with the Twist Drill, it prevents the twist drill from "chattering" or wandering thus enlarging the hole like a cone. Great technique. Thanks.
Interesting to watch, but when the final grinding was done by hand I fail to see the point of wasting all that time using the Lathe plus a Toolpost Grinder? Just learn to grind drills by hand. Yes it takes a lot of practice, and yes they will only rarely be truly accurate, but it's quick, it's very satisfying and the holes will usually be accurate enough for most normal purposes. In any case if you need a true and accurate hole you drill undersize and finish with a reamer.
Most drills do not have a thin web that is of consistent thickness along the drill. As the drill shortens, the web gets thicker so making an effective pilot is impossible. Good for a counterbore with predrilled pilot hole. Dressing the stones is PITA.
Nicely done. Too much of work though, especially when you need to regrind it later. I prefer center drill and normal drill separately. Thanks for sharing!
@@Mastermind- he means drill through with a smaller drill first, then follow it with the larger drill. If you’d followed the centre drill with a drill slightly larger than the web of the drill you used (the web being the solid material between the flutes) your original drill would have cut much closer to size, even as close as your final result if the original drill was sharpened correctly. This is a good idea, but really only useful for production where many holes have to be drilled accurately. For only one or two holes it’s too time consuming and impractical.
There is no need for this. Just check if the main cutting edges are the same on the Drill or the Drill is blunt... Refix this and all is good... Have a nice day and nö offence 😊
hay algo extraño en el minuto 9:19 .. Supuestamente se hizo un orificio con una mecha de centrar. Para continuar con la nueva mecha, pero sin embargo, cuando utiliza lubricante, este parce caer por el agujero que se hizo con la mecha de centrar... Y si esta es no traspasa el material, evidentemente, ¿como puede caer lubricante a traves?? there is something strange at minute 9:19.. Supposedly a hole was made with a centering wick. To continue with the new wick, but nevertheless, when you use lubricant, it seems to fall through the hole that was made with the centering wick... And if this does not go through the material, obviously, how can lubricant fall through? ??
now do a test with a small pilot drill all the way throgh before the 13 mm drill (standard grind 118 deg) - bet that drills nearly as acurate as the fancy grind job - give it a try and let see
Es buena la técnica y la e probado pero un compañero de trabajo casi jubilado ya me enseñó a afilar las brocas o mechas para que perfore con mejor exactitud usando la mecha centro siempre. Lo malo de hacer una mecha de esta forma es que solo la podés usar para perforar pasantes o que no te moleste pasarte de medida con el centro que dejas en la mecha pero es buena muy buena
Ya las venden ... Pero si se puede mejorar el filo... Para romper virutas... Yo las afiló en lija de banda y varían muy poco .. Una de .375 anda abriendo .380-.385 por ambos lados .. Pero si importa mucho el filo y el punto de centro
@@isidroguzman1941 si es muy importante el núcleo o centro el talón es lo que debes variar y sabes cuál es lo más importante el borde del talón asta el filo redondeale un poco apenas y verás el orificio sale a medida lubricante grasa de chancho derretida no falla y una más respeta velocidad con diámetro de mecha y avance para que corte bien también tiene mucho que ver la dureza del material al perforar pero mientras más duro es menos talón😉
I don't see the point to this. A hole that needs to be very accurate still has to be either reamed or helical milled with cutter-comp to fit. Otherwise just hurry and get er done without getting fancy.
That seems like way to much to go threw. If a drill bit is sharpened correctly in the first place it shouldn't cut over size. But to each their own. Pretty cool trick. Thanks for sharing 👍
As a precision engineer there is only one way to produce a size hole pilot drill it open it up and ream it to size even with a drill bit in a collet you won’t get size hole on a hand ground drill bit. Only impressive for those that don’t know. Further more why do it on a milling machine?
@@colinwood387 50 years as an Toolmaker/Machinist the last 25 in Aerospace. I'll say it again just for you. If the drill bit is sharpened correctly in the first place it should not cut over size.
Because the grinding of the original drill bit has no self-centering ability. Just use a small drill to drill a through hole first, and then use a big drill to solve it.😄
I'll have to fashion a drill like that some day, it's a very useful design. As for the proof you show via your calipers that the before hole was over size and the after was not, I am not so sure you're showing what you think you're showing. If you're saying that by NOT using a drill that doesn't have a center drill built into it will be out & wander, that is simply false. For your old drill, your pilot hole may have been too small, so it didn't lead in properly. The drill could've been dull and was more so rubbing rather than cutting, The other explanation is that the legs of the drill before it was sharpened weren't equal lengths-- when one cutting edge is longer than the other, it will wander quite a bit, within the range you showed (anywhere from 5 to 15 thousandths). If you pilot drill properly, and have a well sharpened drill, then the hole will always come out perfect. Also there is the question of how accurate a drill should be. If it's simply clearance, it matters little. If it's for reaming, it matters quite a lot. If it's for a tap, that would depend on how critical the thread is, then you might need an exact minor diameter.
