routing plastic - Router Forums
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post #1 of 7 (permalink) Old 08-16-2019, 06:39 PM Thread Starter
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I have a 1/2 inch thick rectangular piece of white HDPE that has 4 slots that are 1/4 inch wide by 3 1/2 inches running across the width of the piece. I want to round over the edges of the slots. Any suggestions on how to proceed?

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Last edited by Martyc; 08-16-2019 at 06:41 PM.
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post #2 of 7 (permalink) Old 08-16-2019, 07:16 PM
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treat it like wood...

This would have been the week that I'd have finished chewing thru the restraints...
If only new layers hadn't been added....

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post #3 of 7 (permalink) Old 08-17-2019, 02:00 AM
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[
Plastics like HDPE can be worked as if they were wood, as @Stick486 said. However, the feed rate must be much higher in order to avoid melting. If you have scrap try that first. If I were doing what I think you want to do, I would use the following router bit:
https://www.freudtools.com/explore/r...reatment/ovolo

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Last edited by TWheels; 08-17-2019 at 02:05 AM.
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post #4 of 7 (permalink) Old 08-17-2019, 05:57 AM
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Couldn't you treat it a bit like a mortise, but using a bit that'll chamfer both sides and the ends in one pass? Might require a fiddly set up, but it was just a random thought off the top of my head.

Might reduce the amount of heat building up in the bit so it's less likely to melt the plastic as yuo go?
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post #5 of 7 (permalink) Old 08-17-2019, 06:32 AM
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Use a point cutting roundover bit, with a template and guide bushing.

Melting should not be an issue at all when cutting roundovers.
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harrysin and TenGees like this.

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post #6 of 7 (permalink) Old 08-17-2019, 11:20 PM
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As other have pointed out you have to move right along or you will melt. Do not let the router bit sit too long in one spot. Use a plunge router if you have one and if you have to stall out then lift the router bit up and out. So make a dry run of what you are going to do and keep your router cord out of the way. If you are going to use a jig to guide the router make sure you can make a smooth pass and raise the bit at the ends. If you need to back in to clean up an edge you can do that but keep it moving along.
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post #7 of 7 (permalink) Old 08-19-2019, 03:36 PM
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Quote:
Originally Posted by ger21 View Post
Use a point cutting roundover bit, with a template and guide bushing.

Melting should not be an issue at all when cutting roundovers.
@ger21 described exactly how I would carry out the project with one exception, and that is the choice of router bit. I would also heed the advice of @gdonham1 and use a high feed rate in order to avoid melting. My choice of router bit is based on the width of the already existing grooves of which @Martyc wants to round the edges. A point cutting roundover bit would not apply a full 90° roundover in a single pass while an ovolo, a.k.a plunge roundover with a 1/4 inch small diameter would.
While I suggested a Freud ovolo bit, I could not find a Freud point cutting roundover bit!

The two .pdf files linked are exactly the same images as the .png which show the images directly.
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Name:	Whiteside Point Cutting Roundover (2).png
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Click image for larger version

Name:	Whiteside Plunge roundover (Ovolo).png
Views:	5
Size:	93.9 KB
ID:	373083  

Attached Files
File Type: pdf Whiteside Plunge roundover (Ovolo).pdf (8.66 MB, 5 views)
File Type: pdf Whiteside Point Cutting Roundover.pdf (8.24 MB, 4 views)

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-attributed to Chief Seattle of the Native American Suquamish Tribe
  • Wood working, especially router work is too much fun to let "disabilities" get in the way.
  • see MEBCWD's signature line; be certain brain is properly powered up and engaged

Last edited by TWheels; 08-19-2019 at 03:53 PM. Reason: to make it better
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