Drilling Issues

[Dan_S]

I picked up a couple of S&D bits that has 3 flats on the shank. Now all of mine have 3 flats on the shanks

Yea, these are the types you want to have.

this is the set I have.
http://www.use-enco.com/CGI/INSRIT?PMAKA=240-6946

Over the last couple years, I've been switching all my drills over the "triumph twist drill", as every bit I've ever gotten from them have been excellent. My personal favorites are the thunder-bit line.

 

[coolidge]

I use shorter screw machine length drill bits on my lathe and when even they are not rigid enough I use these brute straight flute Hi-Roc bits by MA Ford

 

[HBilly1022]

Yesterday I used Toolmaster's nudge technique to drill an 11/16" hole 2 1/4" deep in mild steel. Initially I used a center drill, followed by a 1/4" bit and then right to the 11/16" bit. The small bit did not wander when entering the cut but the big wanted to. I nudged it into place and it worked awesome. Seems like I learn something new about machining almost everytime I do something on these machines.

Oh, I also hand sharpened my first drill bit, following instructions in a video posted by Tubalcain and that also worked very well. Actually I have attempted to hand sharpen bits before but ............... well it didn't turn out well.

 

[Tony Wells]

That "nudge" method is exactly what I described to you in the second post. I have used it with great success for years. It will always work.

 

[Dan_S]

I am having issues when end drilling on the lathe. I use a centering bit and cut to the top of the taper and that always goes well but when I chuck a drill bit in the tail stock and advance it into the center hole it almost always starts to kick to one side and wobble and then cuts off center. I suspect it is due to my poor drill bit sharpening skills but I'm not sure if that is the only problem. Are there some other causes I need to check out or just become better at sharpening bits properly?

Having just re-read this, the highlighted could be whats causing your issue.

The size of the center/spotting drill hole, should always be smaller than the size of the secondary drill bit. If the hole is bigger, the outer edge of the lips on the secondary drill bit will engage first, and that will almost always make the drill bit walk around. Ideally you want the hole to be just larger than the diameter of the secondary drill bits web, or chisel width depending on how the drill bit it ground.

 

[HBilly1022]

That "nudge" method is exactly what I described to you in the second post. I have used it with great success for years. It will always work.

Right you are and thank you. I guess it didn't really sink in until I seen the video and your absolutely right, it does work very well.

I just reread your post and there is a bunch of other info that didn't sink in on the first read. Apparently old age is really catching up with me. I'm going to try the other points you made and try to remember those too.

Having just re-read this, the highlighted could be whats causing your issue.

The size of the center/spotting drill hole, should always be smaller than the size of the secondary drill bit. If the hole is bigger, the outer edge of the lips on the secondary drill bit will engage first, and that will almost always make the drill bit walk around. Ideally you want the hole to be just larger than the diameter of the secondary drill bits web, or chisel width depending on how the drill bit it ground.

Good to know. I will make sure to remember this for the next drilling operation.

Just as a general question, what maximum size hole do you guys drill before going to boring?

 

[ChipsAlloy!]

Id say the largest your can so the boring operation time is reduced. If you want to bore a 2" hole and only drill up to 1" then you will have to bore a lot of material. Not a big deal cause we have time as hobby machinists but I find it more enjoyable when it doesn't turn out to be too tedious. Leave just enough extra material to make a "zeroing" cut ( so you know exactly what to "offset" ) then a couple light cuts and finish cut. I am sure others will add to this as im not an expert. I did bore holes in the past with success but i certainly dont know all the good tricks! Hope you understand , sometimes my choice of "technical" terms is not the best, English being my second language.

 

[stupoty]

Thanks Bob. Lots of new info there.

I started watching his drill bit sharpening video last night but quit because I couldn't stand the music he was playing. Guess I'll turn down the volume until I get past that part and then watch the whole thing and then watch his drilling vid.

Man this machining stuff is complicated. Who would have thought that drilling a simple hole could be sooooooooo complex, lol. I guess it's only complex if you want the precise diameter and in precisely the right location.

it's ok it only lasts about 15 seconds his video is one of the better ones and keeps it nice and simple on the explanation, reminds me I need to go spend some time at the grinder with a lot of my drill bits

p.s. It is pretty hideous intro music.

Stuart