# Grooves in HDPE plastic



## Dorrumata (Feb 2, 2016)

I'm very new to routing and this is my first project. I'm essentially building a box out of HDPE, which is held by screws.

I'm cutting grooves in 1/2 HDPE plastic board using 31/64" router bit. When I measure the bit, it comes out to 0.4885" and when I measure the board, it comes out to 0.495", so I have about 1/100" difference.
I can't really wedge it in, it should be snug, but removable.
I don't have a micro-adjuster, so I was doing the tiniest bumps on the fence, but it's very imprecise. 
Is there a technique I could use to get the precision I need?

Thank you


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## DonkeyHody (Jan 22, 2015)

That's how I do it. Try it on scrap wood until you get the fit right.


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## Nickp (Dec 4, 2012)

Put an appropriate spacer between piece and fence (card, tape, paper, etc), butt to fence, clamp piece, remove spacer, move fence to piece, turn on, make sawdust...


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## Quillman (Aug 16, 2010)

2 things.

1) Typically there's no 1/1 relationship between cutter diameter and the cutter pathway width. Way way too many variables to chase here.

and

2) NickP has the solution.

Unless you have something like this:
A fence that adjusts continuously and is monitored x travel gage.


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## Dorrumata (Feb 2, 2016)

Quillman, that's very impressive fence. 

Thank you Nick, I will try that.


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## cocobolo1 (Dec 31, 2015)

Quillman said:


> 2 things.
> 
> 1) Typically there's no 1/1 relationship between cutter diameter and the cutter pathway width. Way way too many variables to chase here.
> 
> ...


Holy smoke, what a gem. Do you have a name for that thing? Or is it a custom one off?


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## mbar57 (Apr 20, 2015)

cocobolo1 said:


> Holy smoke, what a gem. Do you have a name for that thing? Or is it a custom one off?


+1 That is awesome!! Where can I get one? What is it called? And what do you use it for? That doesn't matter, I want one!!!:laugh2:


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## Garyk (Dec 29, 2011)

HDPE -UHMW and most of the poly type of plastic are HEAT sensitive which might be your culprit. Try slowing the speed of the router down a bit.


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## Quillman (Aug 16, 2010)

"Holy smoke, what a gem. Do you have a name for that thing? Or is it a custom one off?"
**********************************************************************
It's an evolutionary thing, like last year's car; this year's always sees changes.
That thing started as a router table fence. Then when I understood how to move it back & forth I made a couple of prototypes for the drill press. Then I standardized the parts. It's essentially for drilling and positioning. I call it a Drill Press Fence.


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## cocobolo1 (Dec 31, 2015)

Quillman said:


> "Holy smoke, what a gem. Do you have a name for that thing? Or is it a custom one off?"
> **********************************************************************
> It's an evolutionary thing, like last year's car; this year's always sees changes.
> That thing started as a router table fence. Then when I understood how to move it back & forth I made a couple of prototypes for the drill press. Then I standardized the parts. It's essentially for drilling and positioning. I call it a Drill Press Fence.


You know, considering all the money I waste on food and other essentially useless junk, like gasoline for instance...that's not bad.

Think I would mount mine in an expensive looking glass case with gold trimmed stuff around the outside. I have my thinking cap on.


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