Can the Kreg system be used with Plastic?

[Robert Redman]

I have a project in mind for my boat using the type of plastic that cutting boards are made from only this is 3/4" thick.  Will the Kreg system work with this material?  I would think it would work but want to be sure.  Anyone have any experience with this type material?

 

Thanks,

Bob

[Jay Boutwell]

Hi Robert,  I have used it before making tool jigs and have actually had good luck with using the Kreg system boring the pocket screw holes but elected to use a different type of fasteners over the kreg screw.  I'm sure the kreg screw fine thread would work however in my situation i needed to be able to take it apart often and make difference settings so I taped the holes and installed  "heli coil inserts" in the thread portion and used machine thread bolts.  I did assenble the jig parts with the screws to get the correct placement and angles and then removed them and installed the "heli coils"  I did find that in drilling the pocket holes you need to use a sharp bit and turn the bit very slow as the plastic needs to roll out the top of the bit as it does not break apart as easily as wood.  I also had to add additional clamp pressure to the jig clamp to insure that it stayed where I needed it to be due to it's extream slick surface.  Sure makes nice tool jigs.

[Gary roofner]

Jay that sounds like a great idea that I had never thought about for tempory portable things.

[Gary roofner]

Jay I was wondering if you could give some pictures and sizes of inserts and machine screws

Jay Boutwell said:

Hi Robert,  I have used it before making tool jigs and have actually had good luck with using the Kreg system boring the pocket screw holes but elected to use a different type of fasteners over the kreg screw.  I'm sure the kreg screw fine thread would work however in my situation i needed to be able to take it apart often and make difference settings so I taped the holes and installed  "heli coil inserts" in the thread portion and used machine thread bolts.  I did assenble the jig parts with the screws to get the correct placement and angles and then removed them and installed the "heli coils"  I did find that in drilling the pocket holes you need to use a sharp bit and turn the bit very slow as the plastic needs to roll out the top of the bit as it does not break apart as easily as wood.  I also had to add additional clamp pressure to the jig clamp to insure that it stayed where I needed it to be due to it's extream slick surface.  Sure makes nice tool jigs.

[John Schaben]

Cutting boards are generally HDPE and hold screws very well. Never occurred to me to use pocket screws on the stuff. I use it for shop jigs and usually use spax threads with pilot holes. Try it, you may need to extend the pilot hole into the recieving part though. I'm thinking it may swell around the entry point. If you don't use the pilots, I'm sure you will need to clamp it up very well to keep it from slipping around on you. It has a very low co-efficient of friction which is why I like it for shop jigs.

[Jay Boutwell]

http://smilebox.com/playBlog/4d6a51304d444d774e7a413d0d0a&blogv...

 

This is how I use the helicoils on the HDPE type plastic when I build a jig that I know I will be taking apart and adding different attachements and or just want to be sure I have a jig that will stand abuse.  I have used the kreg screws and they hole well.  on the 90 degree angle attachments and such i use the kreg jig to do the boring and then I asemble it with the pocket screws and then remove one at a time and bore it with the 1/4 inch bit and then  tap it with the special tap and install the heli coil.  On other type jigs i will often just clamp the parts together and drill through with the 1/4 inch bit and tap install the coil and thread in my cap screws.  these come in all sorts of sizes and all threads.  The heli coil were developed for the aircraft industry and i used them in the automotive machinest trade repairing threads and modifying race engines,  I can't begin to tell you how many spark plug threads in aluminum heads that i repaired over my years turning wrenches.

 

the above link is to a musical smile box showing photos of the use of heli coils ,  you can play it full screen by slicking the small icon in the lower left corner of the opened player and close it by using the "ESC" keyboard button.  I hope this will answer the interested members's question and is another method I use to attach hard to do materials.

[John Schaben]

Hi Jay - I like the idea. I've used helicoils on engines before myself. Hadn't thought of using it on HDPE. Been using polycarbonate on jigs that use machine thread fasteners and just tap it for the fastener. It holds threads pretty good but not as well as a helicoil I'd wager.

Back to the OP for a second though. I wonder how well the HDPE would handle the self tapping action of the Kreg screw. I'm sure it would crack acrylic or polycarbonate but polyethelenes are a bit softer.
It looked like you used a pilot hole in the film clip but can't be sure.
Jay Boutwell said:

http://smilebox.com/playBlog/4d6a51304d444d774e7a413d0d0a&blogv...

 

This is how I use the helicoils on the HDPE type plastic when I build a jig that I know I will be taking apart and adding different attachements and or just want to be sure I have a jig that will stand abuse.  I have used the kreg screws and they hole well.  on the 90 degree angle attachments and such i use the kreg jig to do the boring and then I asemble it with the pocket screws and then remove one at a time and bore it with the 1/4 inch bit and then  tap it with the special tap and install the heli coil.  On other type jigs i will often just clamp the parts together and drill through with the 1/4 inch bit and tap install the coil and thread in my cap screws.  these come in all sorts of sizes and all threads.  The heli coil were developed for the aircraft industry and i used them in the automotive machinest trade repairing threads and modifying race engines,  I can't begin to tell you how many spark plug threads in aluminum heads that i repaired over my years turning wrenches.

 

the above link is to a musical smile box showing photos of the use of heli coils ,  you can play it full screen by slicking the small icon in the lower left corner of the opened player and close it by using the "ESC" keyboard button.  I hope this will answer the interested members's question and is another method I use to attach hard to do materials.

[Robert Redman]

Thanks Jay.  I wont need take it apart but I'll probably want to use a coarse thread stainless steel screw and possibly some type of glue or cement.  Do you know what kind of glue would work best with this type material?  I ordered the kreg system yesterday and look forward to trying this out.  Thanks for the response.  When I get it complete I'll try and post some pics.

 

Thanks again,

Bob

[Vijay kunchum]

Great

 

[Jay Boutwell]

John I have screwed several of kreg's fine thread screws into hdpe with pretty good suscess.  It seems to be soft enough that they hold and is actually one of the methods I use in building some jigs.  I bore the plastic on the kreg jig and then just run the screws in and they seem to tighten well and hold.  I just dont know how well they would perform should they be disassembled and re assembled multiple times as I often do with some of my jigs.  However when I build a jig before I use heli-coils, I assemble it with the kreg screw and test making my modifications and then on the critical areas where I wish to disassemble it, I use a bit of apporiate size and just bore through the plastic for the coil insert.  I don't worry about the debth as normally I like to bore all the way through so I can reach in with a pair of needle nose pliers and break off that little hook used for the winder.  It would break off once the cap screw bottoms but just for insurance I like to break it off that way the cap screw doesn't push out one of the coil threads.

In the photos you saw the small holes.  They were not pilot holes for the purpose of being able to screw in kreg screws.   I use the kreg screws to do the initial assembly.  I do this to mark and also to keep the alinement of the angle and actually when I'm building the jig, I just screw it together like it was wood and then remove one screw at a time and drill the hole for the coil insert.   In the photos, I  took it apart and the holes I drilled while it was still assembled and held by the other kreg screws.  Because of its slick nature it is hard to keep it alined . 

 I'm glad you have some experience with heli-coils as when I was doing this post I was wondering how many would know what a heli-coil was and it's principle of use.  A real jewel when it comes to fixing something of value. Have a great day John. 

John Schaben said:

Hi Jay - I like the idea. I've used helicoils on engines before myself. Hadn't thought of using it on HDPE. Been using polycarbonate on jigs that use machine thread fasteners and just tap it for the fastener. It holds threads pretty good but not as well as a helicoil I'd wager.

Back to the OP for a second though. I wonder how well the HDPE would handle the self tapping action of the Kreg screw. I'm sure it would crack acrylic or polycarbonate but polyethelenes are a bit softer.
It looked like you used a pilot hole in the film clip but can't be sure.
Jay Boutwell said:

http://smilebox.com/playBlog/4d6a51304d444d774e7a413d0d0a&blogv...

 

This is how I use the helicoils on the HDPE type plastic when I build a jig that I know I will be taking apart and adding different attachements and or just want to be sure I have a jig that will stand abuse.  I have used the kreg screws and they hole well.  on the 90 degree angle attachments and such i use the kreg jig to do the boring and then I asemble it with the pocket screws and then remove one at a time and bore it with the 1/4 inch bit and then  tap it with the special tap and install the heli coil.  On other type jigs i will often just clamp the parts together and drill through with the 1/4 inch bit and tap install the coil and thread in my cap screws.  these come in all sorts of sizes and all threads.  The heli coil were developed for the aircraft industry and i used them in the automotive machinest trade repairing threads and modifying race engines,  I can't begin to tell you how many spark plug threads in aluminum heads that i repaired over my years turning wrenches.

 

the above link is to a musical smile box showing photos of the use of heli coils ,  you can play it full screen by slicking the small icon in the lower left corner of the opened player and close it by using the "ESC" keyboard button.  I hope this will answer the interested members's question and is another method I use to attach hard to do materials.

[John Schaben]

Thanks for the info. Get's me thinking about some different approaches to some projects I have lined up.... Course, sometimes me starting to think isn't necessarily a good thing:-(

Jay Boutwell said:

John I have screwed several of kreg's fine thread screws into hdpe with pretty good suscess.  It seems to be soft enough that they hold and is actually one of the methods I use in building some jigs.  I bore the plastic on the kreg jig and then just run the screws in and they seem to tighten well and hold.  I just dont know how well they would perform should they be disassembled and re assembled multiple times as I often do with some of my jigs.  However when I build a jig before I use heli-coils, I assemble it with the kreg screw and test making my modifications and then on the critical areas where I wish to disassemble it, I use a bit of apporiate size and just bore through the plastic for the coil insert.  I don't worry about the debth as normally I like to bore all the way through so I can reach in with a pair of needle nose pliers and break off that little hook used for the winder.  It would break off once the cap screw bottoms but just for insurance I like to break it off that way the cap screw doesn't push out one of the coil threads.

In the photos you saw the small holes.  They were not pilot holes for the purpose of being able to screw in kreg screws.   I use the kreg screws to do the initial assembly.  I do this to mark and also to keep the alinement of the angle and actually when I'm building the jig, I just screw it together like it was wood and then remove one screw at a time and drill the hole for the coil insert.   In the photos, I  took it apart and the holes I drilled while it was still assembled and held by the other kreg screws.  Because of its slick nature it is hard to keep it alined . 

 I'm glad you have some experience with heli-coils as when I was doing this post I was wondering how many would know what a heli-coil was and it's principle of use.  A real jewel when it comes to fixing something of value. Have a great day John. 

John Schaben said:

Hi Jay - I like the idea. I've used helicoils on engines before myself. Hadn't thought of using it on HDPE. Been using polycarbonate on jigs that use machine thread fasteners and just tap it for the fastener. It holds threads pretty good but not as well as a helicoil I'd wager.

Back to the OP for a second though. I wonder how well the HDPE would handle the self tapping action of the Kreg screw. I'm sure it would crack acrylic or polycarbonate but polyethelenes are a bit softer.
It looked like you used a pilot hole in the film clip but can't be sure.
Jay Boutwell said:

http://smilebox.com/playBlog/4d6a51304d444d774e7a413d0d0a&blogv...

 

This is how I use the helicoils on the HDPE type plastic when I build a jig that I know I will be taking apart and adding different attachements and or just want to be sure I have a jig that will stand abuse.  I have used the kreg screws and they hole well.  on the 90 degree angle attachments and such i use the kreg jig to do the boring and then I asemble it with the pocket screws and then remove one at a time and bore it with the 1/4 inch bit and then  tap it with the special tap and install the heli coil.  On other type jigs i will often just clamp the parts together and drill through with the 1/4 inch bit and tap install the coil and thread in my cap screws.  these come in all sorts of sizes and all threads.  The heli coil were developed for the aircraft industry and i used them in the automotive machinest trade repairing threads and modifying race engines,  I can't begin to tell you how many spark plug threads in aluminum heads that i repaired over my years turning wrenches.

 

the above link is to a musical smile box showing photos of the use of heli coils ,  you can play it full screen by slicking the small icon in the lower left corner of the opened player and close it by using the "ESC" keyboard button.  I hope this will answer the interested members's question and is another method I use to attach hard to do materials.

[Jay Boutwell]

Robert, I'm sorry but I do not have any idea of any type of glue that would stick to this material.  I'm not even sure if there it can be welded like some of the plastics using the hot air welding torch and filler rod.  Using the helicoil is about the toughtest connection that I can think of.   It if is for something to be water tite maybe a method would be to use a small router or dremel tool and cut a small groove into the mating surface and squeeze in a bead of silicone and then assemble.  The silicone bead would be like a gasket much like the ones we find in water pumps and hydralic components likd in automatic transmisssions.  Might be something to explore.  I don't know what boating projects you are doing however I know a trick from the old days about how to make a water tite joints in wood with out using glue.   If interested for some of your boating projects,  I can explain, should you wish.

Robert Redman said:

Thanks Jay.  I wont need take it apart but I'll probably want to use a coarse thread stainless steel screw and possibly some type of glue or cement.  Do you know what kind of glue would work best with this type material?  I ordered the kreg system yesterday and look forward to trying this out.  Thanks for the response.  When I get it complete I'll try and post some pics.

 

Thanks again,

Bob

[Ken Darga]

''....I don't know what boating projects you are doing however I know a trick from the old days about how to make a water tite joints in wood with out using glue.   If interested for some of your boating projects,  I can explain, should you wish....''

 

Jay, 

re ''boats''

How bout the ''ship-lap'' joints---sealed with ''tar'', ''caulk'', or equiv sealer.

I know that Noah, didn't use ''silicon sealer'', and I'm sure he didn't have a KREG pocket hole drilling guide.

 

I recall, when I was a youngin', helping my granddad, working on his 'ol wooden flat bottom row boats---

repairing/replacing boards and sealing the cracks/joints.

None of his joints had any screws, bolts or equiv metal fasteners.

 

NOTE:  we ''ALWAYS" took along ''bailing buckets---

AND---some ''corks'', (from his brandy and wine barrel stock)---just in case one of the knots, in the wood gave loose.  Those 'ol corks also came in handy as fishing floats.