Author Topic: Upcut or downcut spiral bits for router table?  (Read 2226 times)

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Offline Neal W

  • Posts: 119
Upcut or downcut spiral bits for router table?
« on: August 13, 2018, 07:54 AM »
My experience with router bits (straight bits in particular) is with the typical two flute or one flute straight bits.  Since I've worn out my 1/2" and 1/4" bits, I'm looking at spiral bits from whiteside as replacements.  I will use them both in handheld applications, and in a router table.  Mostly they will be for Dadoes.

Should I be looking at up cutting or down cutting bits?
Turning perfectly good lumber into scrap and sawdust for more than 20 years!

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Offline nvalinski

  • Posts: 44
Re: Upcut or downcut spiral bits for router table?
« Reply #1 on: August 13, 2018, 08:08 AM »
You likely want an upcut bit. It will pull the chips up towards the router, which gives you better control in both handheld and table routing situations. Downcuts, especially on router tables, have a tendency to want to push the wood/router away from each other, though they may give you a slightly better finish on the edges of a dado.

Offline Birdhunter

  • Posts: 2363
  • Woodworker, Sportsman, Retired
Re: Upcut or downcut spiral bits for router table?
« Reply #2 on: August 13, 2018, 08:39 AM »
I agree with the above unless I am routing plywood. The upcut bits can lift the top layer up.... delaminate.
Birdhunter

Offline Roseland

  • Posts: 580
Re: Upcut or downcut spiral bits for router table?
« Reply #3 on: August 13, 2018, 09:33 AM »
I only ever use upcut or straight.

Upcut clear the dust out of a cut quicker, so I prefer them when routing solid wood.  But like the other post says, they can delaminate ply, so then I use straight cutters or go very gently.

Andrew
TS55, MFT/3, OF1400, OF1010, CT26, RS100, ETS125, CXS, MFS400, DF-500, Zobos.

Offline Dick Mahany

  • Posts: 384
Re: Upcut or downcut spiral bits for router table?
« Reply #4 on: August 13, 2018, 09:47 AM »
This video does a nice job of explaining the benefits of different spiral bits

Offline RKA

  • Posts: 1260
Re: Upcut or downcut spiral bits for router table?
« Reply #5 on: August 13, 2018, 10:45 AM »
It depends on what you're doing.  The case for downcuts is to preserve the integrity of the face when dealing with material prone to tear out or chip out.  Also, when using a bearing guided bit and template on the router table I'll use a downcut with the bearing on the bottom of the bit (which is probably the most frequent application I find for these bits).  The template serves as a support to eliminate tearout on that side of the work piece.   
-Raj

Offline ElectricFeet

  • Posts: 80
Re: Upcut or downcut spiral bits for router table?
« Reply #6 on: August 13, 2018, 11:32 AM »
Remember also that the directions “up” and “down” change their meaning when you turn a freehand router upside down to mount it under a table.

So while for freehand an upcut will send dust upwards towards your dust collection, it will send the dust under the table when mounted on a table.

You might also want to look at compression bits, which have both upward and downward spirals. You have to be careful about getting the heights right so that both spirals can engage on the edges. In theory (I have no experience on this) both edges come out clean.

(Those “The router bits” videos from Timbecon are really good. I watched them all the other day — very useful before buying.)

Online Cheese

  • Posts: 5069
Re: Upcut or downcut spiral bits for router table?
« Reply #7 on: August 13, 2018, 12:45 PM »
Here's an example of a dado in maple ply using a Whiteside downcut spiral bit. This dado was made in a single pass.

Offline Dick Mahany

  • Posts: 384
Re: Upcut or downcut spiral bits for router table?
« Reply #8 on: August 13, 2018, 12:52 PM »
Here's an example of a dado in maple ply using a Whiteside downcut spiral bit. This dado was made in a single pass.

That sure is one clean cut.  How was the dust extraction with the down cut bit?

Offline ElectricFeet

  • Posts: 80
Re: Upcut or downcut spiral bits for router table?
« Reply #9 on: August 13, 2018, 01:33 PM »
Here's an example of a dado in maple ply using a Whiteside downcut spiral bit.
Wow. Thanks for the pic!

Online Cheese

  • Posts: 5069
Re: Upcut or downcut spiral bits for router table?
« Reply #10 on: August 13, 2018, 04:04 PM »
That sure is one clean cut.  How was the dust extraction with the down cut bit?

The dust extraction was fine, used the 1010, my favorite. The dado is 1/4” deep.

Offline Mario Turcot

  • Posts: 568
Re: Upcut or downcut spiral bits for router table?
« Reply #11 on: August 15, 2018, 10:43 AM »
Have you also consider Spiral Compression Bits? More expensive but they are worth the price.



"Excellent for creating grooves and dado cuts in plywood and composite materials. Solid carbide compression spiral bits designed for CNC applications requiring high feed rates and a clean finish. Special unique carbide for longer lifetime in abrasive material. Designed for CNC applications requiring high feed rates and a clean finish. Particularly suitable for double sided melamine or laminated material."

Works very well on soft and hardwood. To me this is the best type of bit when it comes to do hand free pockets. Since I use those on my CNC I never looked back.
Mario

Offline Dick Mahany

  • Posts: 384
Re: Upcut or downcut spiral bits for router table?
« Reply #12 on: August 15, 2018, 11:21 AM »

Have you also consider Spiral Compression Bits? More expensive but they are worth the price.

Works very well on soft and hardwood. To me this is the best type of bit when it comes to do hand free pockets. Since I use those on my CNC I never looked back.

I have been thinking about the compression bits and they get good reviews albeit expensive, hence my reluctance to buy one yet.  Have you used them in a router table or hand held router as I don't have a CNC and would be using them primarily on plywood edges and hardwoods ?

Online rvieceli

  • Posts: 848
Re: Upcut or downcut spiral bits for router table?
« Reply #13 on: August 15, 2018, 02:41 PM »
@Mario Turcot thanks for mentioning that hit it reminded me that had one to put in the rotation and hadn’t gotten around to it.

@Dick Mahany just put it in my handheld router this morning and it does a great job. Smoother cutting and a great finish on the cut.


Here's the one I'm using.

https://www.amazon.com/Whiteside-Router-Bits-UD2102-Compression/dp/B0012K5YDK/ref=sr_1_fkmr0_3?ie=UTF8&qid=1534358812&sr=8-3-fkmr0&keywords=whiteside+ud2105

Ron
« Last Edit: August 15, 2018, 02:48 PM by rvieceli »

Offline Roseland

  • Posts: 580
Re: Upcut or downcut spiral bits for router table?
« Reply #14 on: August 15, 2018, 02:58 PM »
TS55, MFT/3, OF1400, OF1010, CT26, RS100, ETS125, CXS, MFS400, DF-500, Zobos.


Offline grobkuschelig

  • Posts: 428
Re: Upcut or downcut spiral bits for router table?
« Reply #16 on: August 15, 2018, 03:36 PM »
There are times I wish I lived in the US of A:

Andrew

There are times you just need to look a little further than Amazon, who are usually ripping you off on everything. ;)

https://routercutter.co.uk/whiteside-ud2102

Offline grobkuschelig

  • Posts: 428
Re: Upcut or downcut spiral bits for router table?
« Reply #17 on: August 15, 2018, 03:37 PM »
Fixed that for ya:

Great minds shop alike, or whatever they say... ;)

Offline Roseland

  • Posts: 580
Re: Upcut or downcut spiral bits for router table?
« Reply #18 on: August 15, 2018, 03:53 PM »
Thanks, I’ll get one!

Andrew
TS55, MFT/3, OF1400, OF1010, CT26, RS100, ETS125, CXS, MFS400, DF-500, Zobos.

Offline Mario Turcot

  • Posts: 568
Re: Upcut or downcut spiral bits for router table?
« Reply #19 on: August 15, 2018, 07:57 PM »
@Dick Mahany
Have you used them in a router table or hand held router as I don't have a CNC and would be using them primarily on plywood edges and hardwoods ?

Unfortunately I only used them on the CNC, cutting 9mm to 18mm BB and some Bubinga, Purplehearth and Shedua. Three pretty hard wood. On the hard wood it was for contour only using a 1/4" bit. I am looking to get some 1/8" and 1/16".
Mario

Offline jjowen

  • Posts: 96
Re: Upcut or downcut spiral bits for router table?
« Reply #20 on: August 15, 2018, 08:19 PM »
Have you also consider Spiral Compression Bits? More expensive but they are worth the price.

I am still relatively new to routing. While I have been forming my own conclusions about which bits are good for what, I found the video really helpful, even if only to confirm my own conclusions.

Re the compression bits; I bought one a while ago and recently got around to trying it out.  I mainly work with high quality birch ply. The compression bit gave a fantastic cut when cutting 'through' with the compression point somewhere in the middle of the material.
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Offline ElectricFeet

  • Posts: 80
Re: Upcut or downcut spiral bits for router table?
« Reply #21 on: August 16, 2018, 03:23 PM »
This is also a very useful article that explains how to choose the correct depth of cut to get the advantages of both the upcut and downcut spirals of a compression bit:

https://www.popularwoodworking.com/woodworking-blogs/cnc-tooling-basics-for-woodworkers-part-three

It also explains why you really shouldn’t use downcut spirals in MDF (tl;dr: dust forced downwards + heat = fire).

Offline Neal W

  • Posts: 119
Re: Upcut or downcut spiral bits for router table?
« Reply #22 on: August 27, 2018, 08:54 AM »
Thanks for all of the very useful responses.  I purchased two whiteside compression bits for my projcect.  A half inch and a 1/4 inch bit.  I was able to use the 1/2 bit this past weekend on plywood and it was terrific.  I never felt like the router was going to push away from the material, and the dust collection from the cuts were very good/exceptional.  They were certainly an upgrade from the two flute straight cutters I had been using. 
Turning perfectly good lumber into scrap and sawdust for more than 20 years!