Blank Drilling issues

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RProctor

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Rialto, CA
I am relatively new to pen turning I have about 12-15 pens under my belt but have the material to make about another 25. I don't have a pen vise but drill with a Jacobs Chuck in my tailstock and my blank in a Nova G3 Chuck with Pen Jaws. I have the Rockler Excelsior mini lathe. Bought it in February (I think) when the carbide pen tool kit was free with purchase. I am experience a lot of heat when I drill....to the point of acryllic blanks and acrylester cracking from the heat to the point of total loss. I had an olivewood blank get so hot the wax melted and it was no longer safe in the chuck. I've tried various speeds, feed rates, how often I clear chips, etc. Eventually I want to move to my drill press and a vise but for now this is what I have. The lathe is 5 speed (belt/pulley change system) of 760, 1160, 1600, 2200, 3200 rpm. I most commonly seem to be using a 3/8 brad point pit. Any thoughts from the wise here are much appreciated. Thanks for your time and make it a great day!
 
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Get a spritz bottle - I use one that used to hold fluid to clean my glasses - and fill it almost to the top with water. Then drop in 2-3 drops of dish washing liquid or liquid soap. Every time you clear the drill, spritz the drill and keep doing it until the water stops boiling off and it is comfortable to the touch. Then spray into the hole and restart drilling. I just got a can of spray drill lube, but haven't had the chance to try it yet, so I'll report back when i have.
 
Brad point drills are not very good for drilling pen blanks, in my opinion.

You are drilling in the best possible way .... you don't need a drill press, which will result in less accurate results.

Your problem may be with your drill bit ... a high quality High Speed Steel (HSS) machinist's drill bit should go through Olivewood quite easily with not much heat

I suggest that you buy such a drill bit from a local tool store (not Home Depot or Walmart). For a 3/8" drill bit, the price should be around $6.
Go for the "jobber size" drill bit of a good brand name ... I buy Norseman drills ... made in USA. Consider a full set in metal case for around $85. You will use many of them if you are serious about pen-making and it could be cheaper in the long run

If you are drilling acrylic, a lubricant is advisable .... like WD-40. Also with acrylester. Clean with isopropyl alcohol after drilling.
 
I start the lathe with my pen blank in the chuck jaws and with sharp pencil mark the spinning center. Another factor is to make sure the dill bit is locked deep in the Jacobs chuck to keep the wandering to a minimum. With the lathe on and the slowest RPM set slowly bring the tail stock forward and just touch the blank Dead Center and lock down the tailstock. Not to say your lathe has play between the rails like mine but if so this puts everything in alignment. Advance the screw on the tail stock slowly 1/4 turn stop repeat ect. ect. If you have a shop vac use it to suck away the shavings as you go. As the drill gets deeper into the blank and the shavings stop coming out back the drill out clear the drill and continue. If at about 1/2 way through the blank your drill starts squealing things are miss aligned, at this point I simply unlock the tailstock the squealing stops lock down the tailstock again !!!! And continue. It's the little quarks of your lathe you may have to contend with as you get time under your belt you'll know just what works and what doesn't. Have fun Bill
 
Randy, it's a matter of personal experience, on my part ... as I said above, "in my opinion".

I would actually contest your claim that .... "It seems most turning sites seem to sell bradpoints for pen blanks. "

I have been to a great number of pen-kit related vendor websites over the years and I don't believe that "most" recommend them, even if some sell them.

And some who sell them have cautioned ... as I recall ... against using them for any blanks other than straight-grained wood.

If you think about the physics involved, it seems to me that a brad point drill bit can't possibly have the rigidity of a twist drill (machinist type).
Also, the material being drilled has some elasticity which encourages the material to "collapse" after passage of the cutting edge.
With a brad point drill, the cutting "blade" occupies a small portion of the bore cross-section, so there can be more collapsing.
When the blade comes around again, there will be expansion. . Successive collapsing and expanding could, as I see it, result in more heat being generated that when using a twist drill. The generally cylindrical and larger surface area of the twist drill is going to resist collapsing better. On top of that, the twisted (helical) edge of the twist drill does have some degree of sharpness, providing additional cutting capability on the sides which a brad point certainly does not have.

These are just my own thoughts and descriptions of things as I see them; I would be happy to hear from others who may have more machine drill experience than I have. I "wrote off" brad point drills very early in my pen-making career some 9 or 10 years ago as being insufficiently accurate and, therefore, difficult to use. I did notice the excessive heat generation at the same time but not to the degree of melting that you indicate.
 
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magpens said:
Randy, it's a matter of personal experience, on my part ... as I said above, "in my opinion".

I would actually contest your claim that .... "It seems most turning sites seem to sell bradpoints for pen blanks. "

I have been to a great number of pen-kit related vendor websites over the years and I don't believe that "most" recommend them, even if some sell them.

And some who sell them have cautioned ... as I recall ... against using them for any blanks other than straight-grained wood.
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Totally understand. Im only familiar with a few sites myself like Penn State and Craft Supply. I'm very appreciative of the feedback and advice.
 
Brad point drill bits are made for woodworking where the bulk of the work is face grain, not end grain like most pen blanks have. The two spurs cut the entrance of the hole cleanly and the point keeps the bit aligned when starting. On end grain it isn't needed that's why a good sharp standard bit is better. In plastics the spurs and point don't cut much therefore cause friction. Save the brad points for furniture making. ;)
 
magpens said:
Brad point drills are not very good for drilling pen blanks, in my opinion.

You are drilling in the best possible way .... you don't need a drill press, which will result in less accurate results.

Your problem may be with your drill bit ... a high quality High Speed Steel (HSS) machinist's drill bit should go through Olivewood quite easily with not much heat

I suggest that you buy such a drill bit from a local tool store (not Home Depot or Walmart). For a 3/8" drill bit, the price should be around $6.
Go for the "jobber size" drill bit of a good brand name ... I buy Norseman drills ... made in USA. Consider a full set in metal case for around $85. You will use many of them if you are serious about pen-making and it could be cheaper in the long run

If you are drilling acrylic, a lubricant is advisable .... like WD-40. Also with acrylester. Clean with isopropyl alcohol after drilling.
Click to expand...
I have to agree with Mal on this one. I used to use brad points but got a lot of "drift" with them which meant I had to oversize the blank so I had plenty of meat to turn the item. I went to drill bits, not brad point, made in the U.S.A., sorry don't remember the brand, and the drifting stopped. I buy them from a tool store (actually named The Tool Box) in Great Falls. I've given up on the cheap imports from Harbor Freight and the big box guys. They have to be sharp and when needed I sharpen them on my Drill Doctor bit sharpener. The ones I get are all HSS. I can call The Tool Box and find out what brand if you're interested.
 
You wrote that you have tried different feed rates, but the is very ambiguous. Feed rate and sharpness/dullness are the greatest contributors to heat. I don' usually use brad points but have done it on occasion.

Since we cannot in words accurately describe feed rate, I will say it like this: In the past and early days of using snake wood, which is very brittle and extremely heat sensitive, some would drill 1/2 an inch by drilling about 1/8 inch bring the bit out, let it set for 5 minutes or so, drill 1/8 inch, repeat 5 to 10 minutes and 1/8 inch and so on to 1/2 inch. Wait a day, and do the same again. I'm not kidding.

What is your feed rate at the slowest? Do you pull the bit out after drilling 1/2 inch or so to clean the flutes of the drilled material? The heat you mentioned usually occurs when the flutes are not cleaned and drilling too fast or too deep to let it eject. Drill 1/2 inch, pull out and clean the ejected material, repeat, repeat, repeat every 1/2 inch.
 
leehljp said:
You wrote that you have tried different feed rates, but the is very ambiguous. Feed rate and sharpness/dullness are the greatest contributors to heat. I don' usually use brad points but have done it on occasion.

Since we cannot in words accurately describe feed rate, I will say it like this: In the past and early days of using snake wood, which is very brittle and extremely heat sensitive, some would drill 1/2 an inch by drilling about 1/8 inch bring the bit out, let it set for 5 minutes or so, drill 1/8 inch, repeat 5 to 10 minutes and 1/8 inch and so on to 1/2 inch. Wait a day, and do the same again. I'm not kidding.

What is your feed rate at the slowest? Do you pull the bit out after drilling 1/2 inch or so to clean the flutes of the drilled material? The heat you mentioned usually occurs when the flutes are not cleaned and drilling too fast or too deep to let it eject. Drill 1/2 inch, pull out and clean the ejected material, repeat, repeat, repeat every 1/2 inch.
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I am pulling out about every half inch and cleaning the bit off with a nylon rush. Others have stated to turn my lathe to the lowest RPM which I had done but lately had increased a step. I will try a non brad bit and see what my results are like.
 
Just returned to turning after an extended absence. In the past I used an expensive drill press with a cross-feed vise. Since most pen blanks are not 4 square, I always had problems with squaring up the blank for a true center hole. Normal result after all my engineering efforts were "catewhampus" holes. Using 5/8" acrylic blanks for El Grande sized holes, 33/64, works - if holes are centered true.

So, using a dead center in the drive an a live center in tail stock I first determined that all was in dead-on alignment. Then I turned my attention to lathe speed. Went back to my drill press and determined I had been drilling blanks at about 300 rpm. I can run my 46-460 lathe ar 250, so that's what I do. I do not use brad point bits. Holes have been perfect.

If the slowest you can run lathe at 750, you'll probably get best results by going REALLY slow which should not be much of a problem unless you're a production house. Highly recommend a mist coolent; if you choose to use DNA - denatured ethanol - just be aware it is flammable and use all caution. I personally would not use water or oils.

Thus the trade-off: speed, use drill press capable of 300 or so rpm, or a better chance at accuracy - use the lathe. Just a side note, I now do everything on the lathe except for initial cutting of blanks, and while not the fastest, I certainly think the finished product is better than before.

Sorry for the long-winded reply.

Don
 
I have the exact setup as you. Same lathe and chuck. I drill at 1100. I use both brad point and HSS. Both get hot in my experience, but not to the point you're talking about. I advance the bit slowly into the blank. Then I completely back it out completely and clean the flutes(?) with a tooth brush. Then I wait for the bit to cool off before starting to drill again. Someone suggested spraying some DNA on the bit to cool it off. I haven't tried it, but that may be something for you to try.
 
One point that may have escaped mention in this thread is one that I find to be a key to success with drilling on the lathe ....

.... that is .... turn the blank round before attempting to drill the axial hole through the blank .... and you do that by first turning between centers.

You have to first mark the geometric center on each end of the blank; then use a small hand drill to drill a 3/16" diam hole 1/4" (or so) deep in each end.
Then mount the blank between centers, with the cones of each center in those small holes. . (It helps to have the blank ends square to the blank axis.)
If the blank is square cross-section there is no problem marking the centers; if not square you just "guesstimate".

You may want to cut the blank to the length of your brass tube before doing the rounding, but you don't have to. You can cut after rounding.

Sometimes you need the axial hole to be fairly long. If you have done the rounding fairly accurately, you can drill the blank from both ends
 
I have read many times here and that is why I do not bring it up much about DNA being flammable. I laugh at this remark every time I read it. You can not bring that bit to a temp where you combust DNA and if you ever got it cherry red you might be doing something wrong You think??????? I made the suggestion here and probably should not have because I do not want to wake the chemists here who have pulled all their charts out and info and tried proving this. But I will continue to always cool my bits with DNA. By the way I drill billiard balls with carbide bits and continue to cool with DNA. But just my opinion.
 
Good info from a large group, sharing their advice and experience. I use a DP. I set it up and don't have to change except for drill bits and pen mill. I found with the lathe it was too time-consuming. The mandrel goes on the lathe
IMG_20171118_060456492_HDR.jpg
and turn the blank. Photo attached of my setup. Vise is from Harbor Freight.
 
I would try using a center drill first, then a 7mm helical bit, then move up to your needed size.

Acrylics, real acrylics not the polyester blanks that catch and shatter (acryluster and the like are not acrylics):
They are not all the same some are softer and some are rock hard like drilling into metal. Because of the variance, I use vegtable oil, and step up in size as I go at about 300 rpm, pulling the bit in and out every 1/2 to 3/4" depends on how hard the acrylic is. It sucks and would work better on a drill press.

Using the center drill allows the hole to start dead center.
Using a 7mm pilot hole, will allow you drill the low velocity center out first, allowing you to work up to a 3/8 or 10mm in steps.
NOTE: After drilling the pilot hole, each time you pull the bit out, be careful that the bit does not get yanked out when you slide it back in. Go slow, do not rush it.

parts:
center drill: https://www.amazon.com/Atoplee-Prem...=center+drill&qid=1562853168&s=gateway&sr=8-8
7mm chip clearing drill bit mcmastercarr, click on the number: 2754A34 $6.05
 
Why are there objections to brad point bits? My experience with them is I get better results - cleaner holes and much reduced chance of a blowout at the end if I use brad-point bits.
 
crokett said:
Why are there objections to brad point bits? My experience with them is I get better results - cleaner holes and much reduced chance of a blowout at the end if I use brad-point bits.
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People just post from their own experiences with any given tool. If you have a bad experience, it's easy to blame the tool. I have a few brad points, they work for as well as any other bit. I always start with a stubby centering bit and a square blank, if I have those things, the hole is always spot on. Wasn't always like that, I struggled at first, changed my methods and now I don't struggle with it. You learn your tools, they all have little idiosyncrasies.


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greenacres2 said:
The kind of heat you describe really adds to the dulling of the bit as well.
earl
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Most bits are made of high speed steel HSS and hold their hardness to about 900 degF. Your blank will ignite before it gets hot enough to dull from heat. It more likely a bit gets dull then gets hot verses the other way round.


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This has already been mentioned, so my post is to repeat (for emphasis) the value of having the ends of the blank be squared to the turning axis. That SHOULD be accomplished by having the end square to the blank, but it could be off a little, depending on how the blank is mounted. So I suggest always squaring the ends to turning axis by a reliable method prior to drilling. This, plus establishing an accurate center point, will help with keeping the drilling on axis, thus proactively avoiding some (not all) drilling problems that result in the drilling effort drifting off axis.
 
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