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Difficulty Drilling Pocket Holes and Screws In ACQ Treated Pine

Drilling pockets holes in ACQ Treated Pine should be relatively easy, but I need to exert an enormous amount of pressure in order to drill to the depth collar. I'm using a Kreg drill bit.  Since it takes such pressure and a long time to drill down to the depth collar, the pocket hole being drill heats up tremendously and I need to stop every few second to allow the hole to cool down.

After I drilled the holes, I used 2 1/2 inch coarse threaded screws to join the two pieces.  In addition, again, it took an enormous amount of pressure to drill the screws resulting in the screw heating up. By time the screws were in, they did not hold at all.

All of this was done on practice wood scraps.

Need to know why the pocket hole protocol is not working. Thank you.

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Clean out the wood chips often during the drilling process.

(I believe the instructions furnished with the tool, advises this).

Lift the drill bit up from the bottom of the hole, so as to allow the drill bit flutes to carry out the wood chips.

Depending on the depth of the drilled hole, it may take several up and down motions to clear out the wood chips.

The spinning drill bit and the wood chips in the hole create friction,

resulting in the wood chips heating up.

Build-up of the wood chips in the hole, also prevents the drill bit from doing its intended job.

Ken, thank you for you reply. I actually had done what you suggested - clearing out the wood chips. But that action did not ameliorate the problem. The drill basically was going nowhere unless I exerted extreme pressure.

Just a thought. Are you sure your drill was set on high speed? Did you try a corded drill? I've found that a corded drill works much better for me.

One other thing is do your very best at keeping the bit going straight thru the bushings & not pulling/pushing it to one side. That will create a lot of friction making it hard to drill.

Some yellow pine deck boards can be very hard too.

I've found most drill bit cutting edges, are not keenly sharpened.

I touch-up the cutting edge, using a machinist "diamond files", to obtain a honed edge.

(xtra-fine (1200) diamond grit gives a keenly sharpened edge).

I've found the EZE-LAP products, to perform the best.

They offer a wide variety of diamond sharpening tools.

 

Using a 2X magnifier  will increase the visibility of the cutting edge.

You'll be able to see the burr on the cutting edge.

Any burr on the cutting edge will reduce the effeciency of the drill bit.

Most drill bits, from the factory, are stone ground.

I've found many factory grinding operations leave a burr on the edge of cutting tool, and need to be touched up.

I've purchased some expensive drill bits--- were not keenly sharpened at the factory.

Examine the cutting edge of your drill bits, using a magnifier, and you'll see that they are not keenly sharpened, when you first get them.

Even a small burr will result in a difficult drilling operation.

FYI

Drill bit cutting is akin to a good quality hand-plane blade.

The factory edge, is not suitable for a keenly sharpened edge.

Even some of the higher quality plane blades are not keenly sharpened, right out of the box.

To obtain a shaving edge, the blade needs to be honed and stropped.

Also, touched-up on a strop before each use, just like using a wood carving tool.

Some of my hand planes are sharpened and adjusted to produce a shave of a .001" of an inch.

Cutting a thin layer is a lot easier and smoother than trying to take too much material in a single pass.

Glen, thank you for your suggestions. I actually did use a corded drill. It was the only method that I was able to drill the pocket holes, but i still needed to exert extreme pressure in order to get the holes drilled.

Once the holes were drilled, I then drilled the screws in, but the screws did not hold at all. The came right out of the piece receiving the screws. The piece I made the pocket holes in was a piece of deck railing (ACQ Pressure Treated Pine) and the receiving piece was a 4x4 deck post (also pine).

Mark,

Perhaps the driving tool torque was to high, that resulted in strip-out.

Start with a lower torque setting, and do the final seating of the screw using a hand-tool.

When the screw bottoms out, you should be able to give it a "quarter turn" without it stripping.

I think it's a good idea to make some practice pieces,

to insure that you are getting satisfactory results, before going to the next step of the final operation.

Also, inadequate thread engagement will result in a joint not holding.

Perhaps the pocke-hole needs to drilled slightly deeper, to get more thread engagement.

TIP

Drill the pocket hole---

drive a screw into the pocket hole, and note how much of the screw thread is exposed.

You'll want full-threads to be exposed.

If you only see the leading edge of the screw exposed, your not getting adequate depth of the screw to grit into the mating work-piece.

Sounds like the bit is dull/broken. If it wasn't before it certainly is now that it's been heated like that. Make sure you are using the correct settings on the jig and correct stop collar position. How are you joining the boards? End grain to side grain or face grain or end grain to end grain? End grain to end grain joints won't hold. Perhaps you could take a few pictures to show the set up and problem. A picture speaks a thousand words.

Ken - Thank you for your follow-up reply. I've researched to the term strip-out and could not find a meaningful definition. I will presume strip-out refers to a situation where the thread formation in the wood created by the screws are stripped-out. (Please correct me if I am on the wrong track here). If my definition is correct, then I do not believe there was any strip-out.

FYI: I have been using practice pieces as mentioned in my initial discussion.

There was plenty of depth of the screws in the mating piece, probably about 3/4  to 1 inch into the mating work piece.

I also researched the term bottoms out, but again could not find a meaningful definition.

Ken Darga said:

Mark,

Perhaps the driving tool torque was to high, that resulted in strip-out.

Start with a lower torque setting, and do the final seating of the screw using a hand-tool.

When the screw bottoms out, you should be able to give it a "quarter turn" without it stripping.

I think it's a good idea to make some practice pieces,

to insure that you are getting satisfactory results, before going to the next step of the final operation.

Also, inadequate thread engagement will result in a joint not holding.

Perhaps the pocke-hole needs to drilled slightly deeper, to get more thread engagement.

TIP

Drill the pocket hole---

drive a screw into the pocket hole, and note how much of the screw thread is exposed.

You'll want full-threads to be exposed.

If you only see the leading edge of the screw exposed, your not getting adequate depth of the screw to grit into the mating work-piece.

Robert - Thank you for your reply. I'm using a brand new Kreg bit from the Kreg K4 Master.  I have the correct measurements for stop collar the 1 1/4 thick board I'm practicing on. I practicing on joining a face grain with another face grain (I believe - according to the images of the end, face, and side (edge) grains I've seen.

Robert Melrose said:

Sounds like the bit is dull/broken. If it wasn't before it certainly is now that it's been heated like that. Make sure you are using the correct settings on the jig and correct stop collar position. How are you joining the boards? End grain to side grain or face grain or end grain to end grain? End grain to end grain joints won't hold. Perhaps you could take a few pictures to show the set up and problem. A picture speaks a thousand words.

"Strip-out"

herein means that the screws threads no longer grip into the joining member.

The point of a Type 17 screw, which are the type of screws that are marketed by Kreg, and other OEM's.

Type 17 screws have a thread-cutting/self-drilling feature, which does not require a pilot hole be drilled into wood.

The point of a type 17 screw, does not have complete threads to the point.

A cut-away feature in the leading end of the screw, is designed to cut threads into a joining member.

"Full threads" are not complete to the tip of the screw, like you would see on a wood screw or sheet metal screw.

Images for type 17 screws.

https://www.google.com/search?q=type+17+screw+point&biw=971&...

Peruse the various wood screws, that are on todays market, so as to get an understanding of the various designs and their intended uses and applications.

https://www.google.com/#q=screws+types&;*

 "bottom out"  

herein means that the "screw-head" has seated into the counterbored hole.

Mark Schwartz said:

Ken - Thank you for your follow-up reply. I've researched to the term strip-out and could not find a meaningful definition. I will presume strip-out refers to a situation where the thread formation in the wood created by the screws are stripped-out. (Please correct me if I am on the wrong track here). If my definition is correct, then I do not believe there was any strip-out.

FYI: I have been using practice pieces as mentioned in my initial discussion.

There was plenty of depth of the screws in the mating piece, probably about 3/4  to 1 inch into the mating work piece.

I also researched the term bottoms out, but again could not find a meaningful definition.

This may sound silly but is the drill turning in the right direction? Clockwise? There's no reason that a treated board should drill that hard unless the bit is dull or broken.

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