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  • Poplar
  • Fine thread 1 1/4" KREG screws
I have used the KREG jig many times, never in Poplar before. This is the first time I have had the wood split when the screws were driven in.

Should I be using the course thread screws?

2013-03-04 19.20.36.jpg
 

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It happens. I try to keep my screw from being so close to the end of the grain on the vertical pcs. I would have suggested the fine thread, but it looks like you are using them.
 

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I suspect the coarse thread will do the same thing, the thread difference is for more grip in softwood (as I understand it). That close to the end, maybe predrilling the holes may help. I suppose it could be that particular piece of wood, maybe too dry or something. Have you seen that happen on the other legs?
 

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Wow, I've put a lot of kreg screws into a lot of wood, including a bunch of poplar. I would use the fine thread screw. Be sure your collar on the bit and the jig is set to 3/4 stock. If it puts the pocket in too deep, the screw will drive too far into the mating surface. Other suggestions.. use shorter screws. Also, not sure about your design but consider pulling the rails back 3/16ths from the edge of the leg. It's typically a nice look on a table and it give some more beef to the outside edge of that leg.
 

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^^^^^^^^^^^^^
+1

I thought Kreg screws were great when I first started. I did one project with them and since have used other joinery methods such as dowels and M&T.

For most applications dowels seem to be just fine. Funny thing is, after a few months, it is easier to use other methods of joinery than it is to find the craig jig and use it.
 

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No, they aren't traditional and I think we all want to learn the M&T but I like the Kreg jig and it makes strong joints. A pocket screw beats a bad M&T but a good M&T beats a pocket screw. Fair statement???
 

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You can dry sticking the screws in some paste wax first to lubricate the threads, but I think they're just being driven in too far.
 

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I know next to nothing about kreg screws but I think this application is in place of a mortice and tenon joint.
If it was a mortice and tenon joint I don't think I would put it so close to the edge of the leg, and that's what your doing with the screw to close to the edge.

Move the apron in.Hope this helps.
 

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Not sure if it's significant since I don't use them, but I do notice that in this particular instance your screws are going in almost exactly perpendicular to the growth rings which means they are almost exactly parallel to any rays and rays are by far the easiest place to split wood.
 

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To make certain that is avoided in the future make yourself a guide bushing for alignment to insert into the kreg hole and bore an anchor hole in the leg the minor diameter of the screw.

The so called self tapping function of the kreg screw just doesn't cut it, so to speak. Their system in this case is just another attempt at a short cut that fails.
 

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clpead said:
No, they aren't traditional and I think we all want to learn the M&T but I like the Kreg jig and it makes strong joints. A pocket screw beats a bad M&T but a good M&T beats a pocket screw. Fair statement???
+1 this makes it an easy choice. Use a GOOD M&T. :)
 

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i've used the kreg a bunch, with a lot of 3/4 poplar, never had a split problem but i've never had a thick corner piece like that either. dumb question but are you sure your jig is set for 3/4? something about the picture looks different from what i'm used to seeing pocket hole wise. also, mine is the master jig but in my case if my face frame is 1 3/4", which I most always use, I drill the two holes closest together on the jig (I think B and C), that keeps it away from edges. and i always use coarse thread, not to say fine thread isnt ok just that i've never had a problem with the coarse, hope this helps
 

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I also agree it looks like they're too deep. A technique I've used when I think they're may be a tendency of the wood splitting is drilling a small pilot hole before using the screw. I mostly use that on hard woods though and wouldn’t think that poplar would split. I use fine threads on hard woods and coarse on most everything else.

I use the Kreg system primarily for assembling cabinet face frames. For me it's fast and works well. Sometimes I do feel like I'm kind of cheating by not using traditional methods. Once I get better at some other techniques I may not use Kreg as much. I always apply glue when using Kreg.
 

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Personally, the only place I ever use screws is for attaching hardware such as hinges, locks, etc. the rest is proper joinery.

I would think though that if the holes were drilled the correct size, allowing only the threads to catch, there should be no cracks.
 

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Being near the end of the leg/post/style and being in close proximity to the other screw both have caused the split. Careful pre-drilling would probably be the only remedy.
Course threads would have made it worse.
 

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Personally, the only place I ever use screws is for attaching hardware such as hinges, locks, etc. the rest is proper joinery.

I would think though that if the holes were drilled the correct size, allowing only the threads to catch, there should be no cracks.
The screws are self drilling. And 98% of the time they are. When you get very close to the edge or in very hard woods like Hickory you can get splitting and you need to pre drill which can be difficult.
 

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I gotta go with either the screws are too long or the collar is set to drill too deep (making the screws too long into the corner piece).

Check the back of the box that the screws came in. Should be a chart for screw length for stock thickness and when to use fine / course threads.
 

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wont ya love creating an advice monster on here?? lol I won't blab on to much but I re-read ur first post and saw you mentioned you were using fine threads. I bought a box once by accident, and they did everything wrong, came through the front of my frames, split, etc. sometimes you have to actually back off the "3/4" setting on ur collar and jig just a bit, i know the master jig has pre-set stops but it can be tweaked just a bit. sorry for the frustration and hope you get it fixed right! guys that do M & T and natural joining are my heroes, but for quick, repetitive production, a pocket hole is the only way to go IMHO!
 
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