gun drill problem

BHQ

BHQ

we'll miss you
Silver Member
my .750" drill is a few years old now,
i'd say it's due for a good sharpening

it's drilling ok, just taking longer & slower,
the problem comes when backing it out
as if the hole is closing up

getting stuck, so stuck that it actually stopped the lathe:eek:

had to keep going from forward to reverse dozens of times to be able to back it out a couple inches at a time,
then back to the forward & reverse again and again to back out a couple more inches
all this just started with the last few pieces i've drilled this week

i sent sterling an email this morning about possibly getting it re-tipped up to .760"
have no idea if that's possible or not
 
got my answer

thanks john

let ya know what sterling says about re-tip when i hear from them
 
Sounds like it's heating the wood up as you drill then cooling and shrinking after a bit then when you back it out it's smaller than .750.
 
Craig Fales said:
Sounds like it's heating the wood up as you drill then cooling and shrinking after a bit then when you back it out it's smaller than .750.
Click to expand...

exactly what it's doing
sterling got back to me
they can re-tip mine up to the .760" for me for about $110
or i can just get a new one made
 
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BHQ said:
exactly what it's doing
sterling got back to me
they can re-tip mine up to the .760" for me for about $110
or i can just get a new one for made
Click to expand...

The tip is 80% of the drill's price.
I broke a tip one time.
 
BHQ said:
my .750" drill is a few years old now,
i'd say it's due for a good sharpening

it's drilling ok, just taking longer & slower,
the problem comes when backing it out
as if the hole is closing up

getting stuck, so stuck that it actually stopped the lathe:eek:

had to keep going from forward to reverse dozens of times to be able to back it out a couple inches at a time,
then back to the forward & reverse again and again to back out a couple more inches
all this just started with the last few pieces i've drilled this week

i sent sterling an email this morning about possibly getting it re-tipped up to .760"
have no idea if that's possible or not
Click to expand...


Hey Brent,

Just to compare notes:

I drill at 400 rpm with my .750 sterling and have cored over 200 pieces with it. It still is cutting very well and seems to have a good edge still. Heat is the biggest enemy to carbide.

I also use Bostick Dri Cote on my tools for coating the carbide .before and after use.

I also have my drill hooked up to my tail stock not the saddle and tool post. I have to re overhaul the TS and drill between insertion for every 2 1/4 inch or drill pecking which I feel reduces some residual heat that may build up without pecking.

I also have a large receiver tank so the air is constant throughout the process.

No problems with heat or the drill for me till now but every tool has a life span, maybe your just hit the wall with yours.

Rick

http://www.amazon.com/10-75-Bostik-...=UTF8&qid=1362155366&sr=8-3&keywords=dri-cote

BTW, using this stuff on my mico mills for my CNC has extended the tool life by a factor of 2 to 3 times along with keeping the flukes clean with a small brass brush. The pith that is present comes off very easy using this stuff. The carbide blades on my saw machines stay super clean also . This stuff save tons of money for me.
 
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Turn the air on,.......


Lol

Just kidding.

When my gun drill gets sticky I wipe some cue wax on the head of it..and it slips right in.... no pun intended... try it

Kim

Sent from my SAMSUNG-SGH-I727 using Tapatalk 2
 
You all know controlling the heat generated is the key. Resharpening when it is only dull, takes much less to get back to sharp as to waiting untill it is stuffed.
Speed and feed is the answer and it varies to the materials being drilled.
As a guide for me , if I feel any heat in the wood being drilled it is either a dull drill, too many rpm or not enough feed and the drill is rubbing and not cutting.
I drill on the slow side at about 350 to 500 rpm range and a feedrate of .1mm/rev (.004 inches)
 
I've been coring between 40 - 75 cues a year for about 13 years now with the same .750 Sterling bit with no problems so far. Depending on the material, I normally bore at around 450 rpm and increase the air pressure enough so that I feel very little heat from the material or the drill. Highly figured Curly Maple gives me the most trouble.

Dick
 
rhncue said:
I've been coring between 40 - 75 cues a year for about 13 years now with the same .750 Sterling bit with no problems so far. Depending on the material, I normally bore at around 450 rpm and increase the air pressure enough so that I feel very little heat from the material or the drill. Highly figured Curly Maple gives me the most trouble.

Dick
Click to expand...

I have only made about 40 cues and I bore about 900 rpm with 40 to 60 lbs of air pressure. My drill is a metal style with 2 flutes and is 28 inches long. I really do wax the tip of the drill 2 or 3 times with a long piece. I also have found that curly maple is the hardest to bore. It's tough stuff.

Kim
 
Brent, I didn't read all of the posts here, so It's probably already been mentioned, but It's been My experience with drill bits in general... that when they do this they are getting hot, in turn expanding the bore, and then It's closing up around the bit as It contracts, that causing the bit to lock up. several things can happen the work piece could spin inside of the jaws, drill bit spin in the chuck, belt could slip, and in some cases could even stop a motor.
 
Cue Crazy said:
Brent, I didn't read all of the posts here, so It's probably already been mentioned, but It's been My experience with drill bits in general... that when they do this they are getting hot, in turn expanding the bore, and then It's closing up around the bit as It contracts, that causing the bit to lock up. several things can happen the work piece could spin inside of the jaws, drill bit spin in the chuck, belt could slip, and in some cases could even stop a motor.
Click to expand...
upon further inspection, comparing the older .750" to my newer .640",
it's just dull as hell to the touch of a finger
the .640" could cut me , the .750" would bruise me :D
i'll send it to sterling to get re-tipped to .760"
 
BHQ said:
upon further inspection, comparing the older .750" to my newer .640",
it's just dull as hell to the touch of a finger
the .640" could cut me , the .750" would bruise me :D
i'll send it to sterling to get re-tipped to .760"
Click to expand...

You can't use them to drill holes in the basement wall to put in a molly or 2 to hold up a shelf. They will get dull.

LOL


Kim
 
BHQ said:
upon further inspection, comparing the older .750" to my newer .640",
it's just dull as hell to the touch of a finger
the .640" could cut me , the .750" would bruise me :D
i'll send it to sterling to get re-tipped to .760"
Click to expand...

If it were me, With the little difference in the cost between a new one and having your present one re-fabricated, I would have the .750 one resharpened and purchase a new .760. In this way you could core most of your dowels in advance at .750 and then, later, when you are going to build a cue with a dowel bore it with the larger one so as to correct any movement that may have occurred.

Dick
 
rhncue said:
If it were me, With the little difference in the cost between a new one and having your present one re-fabricated, I would have the .750 one resharpened and purchase a new .760. In this way you could core most of your dowels in advance at .750 and then, later, when you are going to build a cue with a dowel bore it with the larger one so as to correct any movement that may have occurred.

Dick
Click to expand...
good idea,
thanks dickie
 
BHQ said:
upon further inspection, comparing the older .750" to my newer .640",
it's just dull as hell to the touch of a finger
the .640" could cut me , the .750" would bruise me :D
i'll send it to sterling to get re-tipped to .760"
Click to expand...

Or you just sharpen it. Last summer at a garage sale I found a brand new green wheel for carbide. $3.00 out the door.
 
Mc2 said:
Brent, what is the cost difference of re tipped to new. I would be interested in getting the old one from you for the difference.

JIm.
Click to expand...

they said $110 to re-tip
about $150 for new one
i'm going to keep this one jim
 
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