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Discussion Starter #1
Hello everyone, first time posting after lurking these forums for a few weeks. I hope this is the right place to post.

I have been working with polycarbonate /lexan for a good few years, but only recently purchased my first "real" router (a Dewalt DW611 PK). Prior to this, I was making due with a Dremel fixed to the plunge-base accessory.. Obviously not ideal, but with some quality 1/8" spiral upcut bits I was able to get results. Now with my 611 I can see how much time and effort was wasted ising my old setup! It's like going from cutting steak with a butter knife, to butter with a steak knife!

My first trials were done using a 1/4" solid carbide spiral up cut bit, KCT137388, made by Kodiak. Wow. My only issue is the cutting length of the spiral being 1.5" makes this bit just a tad too long in my plunge base to where it's protruding about 1/8" from the sub base wish the plunge at full height - however, since i'm using a 1/4" (height) template guide bushing, this is negated.

I am working on a 1/4" thick piece of MR10 polycarbonate, doing some letter cut-outs. As my deadline is fast approaching for completion, and realizing 4-inch-tall lettering done with a 1/4" bit will result in the letters having too much of a rounded corner, I was in need of a smaller diameter bit. Ideally I would pirchase via Amazon but I don't have time to wait on shipping now. I can't use my old 1/8" spirals since the stock collet on 611 only takes 1/4", and i've yet to purchase an reduction adaper and/or smaller collet assembly. So, I was left with just one option.

I purchased a Freud 75-100 two-flute up cut spiral bit, 1/4" shaft, 1/8" diam cut, 1/2" cut length solid carbide bit for 25$ at my local County Store (True Value affiliate, I think). I've yet to use it, I'm just super cautious as I've already lost money on this project with mistakes/mishaps using the old setup,and I would hate to break this pricey bit, mess-up my piece, or both.

So I guess I am hoping to get any experience, opinions, tips etc from anyone using either Freud brand in general, or similar bits on polycarbonate, or other materials even. I think this should work fine as lonf as I am careful - from what I've read in reviews, I see a polarizing result of 5 stars and 1 star, the 1 stars all to do witb bit-breakage. I gather that the reduction bits like this (1/4" to 1/8" etc) are more prone to breakage near the tapering transition, thus the operator must be careful to plunge and feed shallow - yes?

Also always important is the feed direction. It wouldn't hurt to get a refresher in that area, as I'm still fairly green in routing: when working on outside edges, we feed counter-clockwise, and when working on inner cuts (letters, in my case) we feed clockwise? One part that confuses me is what direction do we cut on our initial plunge/feed, before we have any edges at all? I go clockwise/left-to-right - is this correct, and does it matter?

Thank you all!
 

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Well, even being extra cautious, as clean as the cuts were doesn't justify 25$ for only a few passes before the bit snapped. Was during a cleanup pass, too, just milling the edge of the "K" cutout.

If anyone can help advise, I would like to find a decent collet/nut for 1/8" shanks. I've probably seen the limited choices already, but maybe I'm missing some. I don't need something with crazy CNC precision tolerance just something at least on par w the 1/4" OEM collet and nut. I can't shell out 80$ just for a nut and collet kit.

I know reduction collets are fairly cheap, but how well do they perform? There is one on amazon that sounds like it may suit my needs ~10$ but i am not wanting to suffer an injury to save a few bucks. Do they hold, and cut straight? They just slip into the 1/4" collet, yes?
 

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Discussion Starter #3
Could a mod here please move this thread tovthe portable router area of the forum, and maybe change the title to DW611 - go with new collet/nut, or reduction collet, or 1/4-1/8" bits?

Thank you!
 

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Just a few facts.
PC has to be anti-climb cut, inside or out.
So always cut against the cutter rotation.
Flute length should be as close to work thickness as practical.
And if fragility is an issue: Use a single flute, solid carbide, no spirals.
CNC milling is another matter.
And to minimize breakage, stage cut, clean up the swarf as it's created and clamp the hell out of everything. Nothing can swing against the cutter.
 

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My Hitachi M12V only has 1/2" collets available. They don't make a 1/4" so they supply a reducer bushing with it instead and I've never had a problem with using it.

Onsrud makes bits specifically ground for cutting plastics. All of them are straight bits, some with one flute, some with two. They have a super customer service dept and they can tell you what is the best bit, cutting depth, and feed rate. I suggested them to a former member who was using a CNC and had been using Amana bits and getting poor life span and he said with Onsrud the bit ran much cooler and outlasted the Amanas several times to one. I don't have a number or link but you can google them. They are officially Onsrud Cutter 2010.
 

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Discussion Starter #6
Thank you both, very helpful information.

The reduction sleeve I was thinking about grabbing off of Amazon is this[edit: can't post links] Amana RB 104 Reduction Bushing.

Regarding bit type/design, I knew single fluted was best on PC, but i thought spiral was a good choice over straight for cutting thru material?
 

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Rockler sells them for about $4 I think but I don't know if they are as good as the Amana ones. Lee Valley sells them up here for $4.80 Canadian and Lee Valley rarely sells poor quality. I'm pretty sure they test most of what they sell before they put it on the market.
 

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I haven't really tried 1/8" router bits, but I bought the 1/4-1/8" reducing bushing and used Roto-Zip bits in my DW611. I was free hand following patterns on 1/4" plywood to make large Vegie Tales characters for the church, using a styrofoam sheet as a backer to reduce tear-out. I did break a few bits, but I was loading them pretty hard (tight schedule). My only suggestion to avoid breaking the 1/8" bits is to position the bit as deep as you can in the collet, so the cutting edge is as close to the collet as you can get it, and then plunge as deep as you can, to use the very top part of the router bit for everything except the straight down plunging action. Keeping the collet as close as possible to the cut avoids bending the bit as much as possible. Use a styrofoam backer to bury the excess bit below your work and reduce tear-out on the back side.

The Roto-Zip bits that I used are down spiral. For what you are doing, a two blade straight cutting carbide bit will be your best choice. I have never had good results with single edge bits, except for laminate trimming. They vibrate too much when trying to remove significant amounts of material, like when cutting rabbets and dados.

Charley
 

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Thank you both, very helpful information.

The reduction sleeve I was thinking about grabbing off of Amazon is this[edit: can't post links] Amana RB 104 Reduction Bushing.

Regarding bit type/design, I knew single fluted was best on PC, but i thought spiral was a good choice over straight for cutting thru material?
The reduction sleeve you show is to reduce 8 mm to 6 mm. You need a 1/4" to 1/8" reducer.

This is the one you need:
https://www.amazon.com/Amana-RB-102...-fkmr2&keywords=router+reduction+bushing+1/8"
 

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Discussion Starter #11
I must have copied the wrong title, i did add the right size to my cart :)

Thanks CharleyL for the info.
 
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