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Old 09-11-2018, 07:54 AM
Terry Williams Terry Williams is offline
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Join Date: Mar 2012
Location: Naples, FL
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Default 5" long bit for pilot hole in pvc trim

Hi all,

I finally have moved my shop equipment (in storage for 4 years) from Missouri to Naples Florida and I am setting everything up in my shop over the the next week or so.

One of the first jobs I need to finish is trimming some PVC hurricane windows out with PVC trim.

The construction method used for the building is Insulated Concrete Forms with extremely rough, deep openings leaving no where to efficiently attach the trim.

I made a jig to drill two concentric holes in the edge of the trim board about 5 inches deep (1/4" for 4" then 1/8" for screw pilot in final 1").

This works very well, but the bit's tend to "walk" a bit over that length in PVC.

I was thinking about using the router (510 Cobra with extended Z) to drill the holes more precisely - I would set the trim boards side by side and drill as many as possible in one session.

Is there a 5" bit with 1/4" shank reduced to 1/8" over last inch that would be suitable for this?

Thanks for any suggestions or ideas!

Terry
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  #2  
Old 09-11-2018, 08:37 AM
John B John B is offline
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Join Date: Nov 2017
Location: Comfort, TX
Posts: 17
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If there's no bit like that available, it seems to me that you could drill "as deep as you can" with a pointed 1/4" bit (maybe the full depth of the 1/4" hole) and then "finish" with a manually drilled hole for the 1/8" part.

I doubt you'd get much (if any) drift with the 1/8" bit if it starts out centered in the bottom of the hole.

I know they make bit extensions with a diameter as small as 1/8", so...if you located one that fits nicely in the 1/4" hole, you'd be doubly sure of the accuracy of the 1/8" pilot hole
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Old 09-11-2018, 10:15 AM
Jim_in_PA Jim_in_PA is offline
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Join Date: Jan 2018
Location: SE PA
Posts: 653
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Quote:
Originally Posted by John B View Post
If there's no bit like that available, it seems to me that you could drill "as deep as you can" with a pointed 1/4" bit (maybe the full depth of the 1/4" hole) and then "finish" with a manually drilled hole for the 1/8" part.

I doubt you'd get much (if any) drift with the 1/8" bit if it starts out centered in the bottom of the hole.

I know they make bit extensions with a diameter as small as 1/8", so...if you located one that fits nicely in the 1/4" hole, you'd be doubly sure of the accuracy of the 1/8" pilot hole
...and just flip the boards for the final 1/8" cut from the other side. If you are centering the holes in the material, they should be located dead center when flipped if you are careful.
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