So this needs to happen a couple of hundred times. 3/4" bradpoint into endgrain 6" deep. Obviously, friction is my enemy. What options do I have for lubrication/cooling that won't screw with my finishing?
So this needs to happen a couple of hundred times. 3/4" bradpoint into endgrain 6" deep. Obviously, friction is my enemy. What options do I have for lubrication/cooling that won't screw with my finishing?
Nothing that I know of. The way to control heat is by finding the right speed setting and the right feed rate for the job in hand, and having a sharp drill bit. Spinning the drill too fast and feeding the drill into the wood too slowly are what create heat in my experience. Also running a vac with a small nozzle next to the hole will help to pull the debris out faster, I think, and save heat.
Zach
Hi Johnny,
I have used Ivory white bar soap for many years as a lubricant on wood screws or sheet rock screws when I am driving them into harder wood. I apply it dry by just rubbing the screws onto the soap bar. I would imagine this would help with drilling as well - as long as the bar soap residue does not affect your finishing.
David
I've tried soap, beeswax and paraffin. In my experience unlike screws, anything you apply to a drill, will either get wiped off after just a few holes or will boil off due to heat even if reapplied. Drilling that size hole that deep in one operation is going to produce a lot of heat, you can reduce that by clearing chips several times as you drill each hole.
Lee Schierer
USNA '71
Go Navy!
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I drill deep holes on the lathe with a Forstner rather than a brad point. From the first touch of the bit I direct a strong stream of compressed air at the back of the bit and down the hole as it deepens. The air keeps the bit cool while blowing the chips away from the cutting edge and out of the hole. Nothing is new under the sun, but I never heard of anyone using this method. Since the first time I tried it, I haven't drilled without the compressed air.
My holes are usually larger diameter than 3/4" but perhaps this would work for you. It's guaranteed not to mess with your finish! (unless you don't filter your compressed air)
JKJ
I'm with John...and the best and only way to mitigate heat is to cut, back to clear, cut some more, back to clear, etc. Just like with larger "more automated" machines, you need to clear the chips and they do take heat away at the same time.
--
The most expensive tool is the one you buy "cheaply" and often...
I can't think of any lubricant that wouldn't gum up the sawdust and chips on the way out. I have found that bright finish bits seem to let the chips slide out easier than oxide or other rougher finishes. TiN would probably work also. A faster (i.e. longer) spiral might help also, but it also might get jammed faster also, depending on chip size.
As mentioned above, feed rate is very important, as the chips are the main way to remove the heat. For mortices, I mount a shop vac hose next to he hole, which helps with chip clearing, both while drilling and backing out.
Wood selection is also important. Gummy woods like resinous pine will be miserable, and sugary woods like cherry might want to burn. Beech tends to be clean and free cutting, but may or may not work for your application.
Last edited by Andrew Seemann; 11-30-2019 at 10:03 PM.
I would say use a coolant through drill and run compressed air through the bit and out the sharp end. Of course then you have to have a coolant adapter which is normally used on a lathe not a drill press.
Bil lD.
Thinking outside the box. Could these parts be made in two halves and then glued together? If so that would let you run a half round flute bit on long stock, glue up, and cut to length.
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“If you want to know what a man's like, take a good look at how he treats his inferiors, not his equals.”
At the mill, we use biolube to lubricate circular saw blades and guides for the bandsaw blades. The lumber is rough and wet ( not kiln dried ) at this point. I don’t know how it would work as a drill lubricant or if it would affect finish. I know it does not stain white hardwood such as maple.
I haven't tried it, but what about talc?
I think lots of ins and outs to clear chips is going to be your best bet.
When I worked in the toolroom I always "split the point", on most of my drills and I even did my center drills. I could drill a hole through tool steel faster then most other toolmakers that did not do this.And my drills stayed sharper longer, and drilled straighter holes.
You would need a 100 grit grinding wheel with a medium to hard wheel and an optivisor helps with smaller drills.
If you do not know what splitting the point means then look for drills with a 135 degree point. They usually will have them already ground from the factory.
Splitting the point reduces pressure at the very point of the drill, and this helps to drill faster feeds and less friction.
Also using a drill with 5% cobalt would stay sharper longer and you could increase your speed and feed.