Smoke
- Thread starter lockwood
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I know what you mean! :grin-square:
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Well, a lot can depend on the type of bit, but most of the ones I've used worked without smoking, although they can heat up easily, so It can happen, and not like I have never experienced It Myself. I can remember way back one time when I got a piece so hot that It actually caught some sawdust around My lathe on fire.
I drill with a undersized bit, and then end up boring the last part with a mini boring bar for accuracy.
Just out of curiosity are You sure that the lathe is spinning in the direction of the cutting side of the drill bit?
On the speeds I run, I don't have a tach to give me the RPM's, so anything I could say would be a wild guess, but I can run several speeds without It happening. If the hole is getting that hot, then another idea Is to chip drill, or drill a little bit, let the piece cool down, drill again, let cool, etc. heat build up is a bad thing. It can cause material to melt, distort, or get so brittle that it weakens the material and makes It more prone to cracking or splitting.
Greg
None. My guess is you are using a twist drill bit that is better suited for metal. The heat and smoke comes from the bit not clearing itself. Once the wood builds up in the threads it presses against the sides of the hole and begins to heat up in a few seconds. You can also use something on the bit to make it more slick so the wood chips push out a little easier and keep it clear. Mainly you need bits that are designed for wood.
http://www.argos.co.uk/wcsstore/argos/images/432-7170483IEUC545632M.jpg
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Your comment "The bit is new", does not mean it is the correct grind for the job you are doing. You may have to regrind bits often through a little experimenting with your own custom grinds to get the best results for what you are doing. Drill bit sharpening as well as custom grinding you own cutting bits for you lathe are all part of the job.
You can make any bit smoke if your speed is too slow and your applying too much pressure, let the equipment talk to you, it will tell you the correct speed. Start somewhere around 1200 rpm or slower then adjust according to the results you're getting. Don't be in a hurry, you want a precise hole not a fast one. 
Mario....who loves carbide bits.
Mario....who loves carbide bits.
That is a good question about the direction. When I am facing the lathe it is spinning away from me, clockwise. Is this the right way?
Thanks,
Jon
You can make any bit smoke if your speed is too slow and your applying too much pressure, let the equipment talk to you, it will tell you the correct speed. Start somewhere around 1200 rpm or slower then adjust according to the results you're getting. Don't be in a hurry, you want a precise hole not a fast one.
Mario....who loves carbide bits.
A guess with My old motor which worked fine may have been around 1000-1200rpm. My new motor runs much faster, not sure of the RPMs, but I'm only running the variable pot at a hair over 1/4 of the maximum speed, although I can go much faster then that. Like you mentioned though, It's more accurate when I keep It under control. I still want the initial step drilling to be accurate, but It's main purpose for Me is just for material removal. I always follow up with a boring bar, or a 6 flute carbide reamer.
Some of the Drill bits I use are just standard, coated, HSS, or carbide drills. no special grind or anything that I am aware of. I have also bought several machinist drill and reamer lots over the years though, so some of them are a pretty good mix I suppose. Most are for metal though, some even have the oiler/air holes in them Like gun drills do. I have some wood bits with the Forsener looking grinds, they are designed for wood, but for some reason I don't have much luck with them' like some other people do. They cut well, but tend to walk on me. Possibly something I'm doing wrong, or the drills just aren't of the same type, and as accurate as what others use.
The main problem I would have with forcing the drill would be accuracy, They tend to walk more If I force feed the tail stock, but for sure It can build up heat doing that as well. I usually check the material By touch to make sure I'm not overheating It before it gets a chance to smoke up, but for the most part, just from past experiences I can foresee overheating ahead of time by how well the drill is cutting and how easily the material is being removed.
Which reminds me one other thing for the poster is to make sure you are blowing any material out of both the drill Itself and the hole. If the waste gets forced between the sides of the bit and hole, it will create more friction, and build up heat even faster.
It should be spinning toward you. They do make bits that cut the other direction though, but when facing It should be going counter clockwise anyhow.
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NO. Should be going counter clockwise.
Yes counter clockwise in relation to standing on the tail stock end and facing facing the chuck
Normal drill bits are RIGHT HAND....so the lathe must spin to the left side to drill (counter clockwise)
If you were using a Left Hand bit then it would be spinning to the right (clockwise) and not very many people use Left hand bits......their most common form is the Backout BIT....for when you break a bolt or screw, the bit will bite into the material and you can back it out slowly.
I'm sure this confuses people as using the lathe the drill bit is stationary so its completely opposite of using a normal hand drill and bit. Since the bit doesn't turn in the lathe you have to oppose the spin of the spindle to the cutting style of the bit.
Def. easy to mix up for the non seasoned
PS: get a good set of bits with a titanium coating or something similar (a must for drilling phenolic and varying metals)........they will last longer and cut smoother. Make sure that your tail stock is centered along with the center of the chuck, if its not the the bit will be in a bind when drilling and that could definitely cause the wood to smoke.
Drilling hard material isn't what dulls your bits, bits are tempered way over what they are designed to be cutting (so long as your using the correct bit)
What kills bits is HEAT!!! Don't sit there and burn up the bit worse, if its giving you too much trouble drilling it out then you either have the wrong kind of bit or the bit is way dull or your trying to drill too big of a hole. Use pilot bits and work your way up to the final size b/f boring it out to complete the hole.
Another reason to use pilot bits and work your way up if drilling out a larger diameter hole.......using a larger bit you create more stresses on the wood, if that large bit binded good somehow I could see it making whatever your drilling blow up, or just as bad shatter the bit.....DANGEROUS, take the time to do your pilot hole and step up to the final size (then bore of course....can't say that enough), its safer for you, your equipment and your cues.
I don't know if anyone uses UNIbits (I don't on cues but I do offshore) Regardless of cue work, if you ever buy a uni-bit (stepper bit) DON'T EVER BUY THE GREENLEE BRAND, TRASH!!!! UNI-BIT or LENNOX are the brands to go with. Wouldn't matter which if you used it on wood, but the greenlees dull very quick when cutting metal, its cheap metal and not tempered correctly. If you don't have any of these get you a couple, they do come very much in handy around the house/shop, especially if you build jigs and such things.
-Grey Ghost-
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Assuming your spindle speed is not a problem, then, in a word...Guhring. I have several guhring drill bits and a couple SGS, both are solid carbide.
The Guhring drill bits are some of the sharpest carbide drill bits iv'e used. The SGS are good as well. But good sharp carbide drill bits, and the right spindle speed, should stop wood burning.
The Guhring drill bits are some of the sharpest carbide drill bits iv'e used. The SGS are good as well. But good sharp carbide drill bits, and the right spindle speed, should stop wood burning.
wow....this is a simple task that seems so complicated....do you have any 1/4 hss endmills...drill a pilot with it as it wont walk and then follow with a 5/16.....I belive you said you were drilling a new tenon........always use carbide if possible....and the very best way is to bore....if your getting smoke your not doing something right and I have found speed is a good thing if your using the right cutters....not metal bits but forestner bits or endmills.......forestner bits are a good way to go on the cheap......pm me if you got any questions....