Router template guides

[nms]

Hey guys, love to get your input on this..

last time around, I just had a CNC shop cut the slots shown in the attached image, but I want to get setup to do these myself moving forward.

The slots are 3/4" wide, and I'd like your advise on 2 things:

1. Which type of template guide would you recommend?
The brass ones are only $6.50 plus $4 for the ring nut:https://www.leevalley.com/en-ca/sho...-16-inch-and-1-3-4-inch-brass-template-guides

Or should I go with these type of guides which are $26/ea:https://www.festoolcanada.com/accessory/486031---kr-d-24of-900

I'm leaning toward the brass option. Seems like they'd function the same, but curious to hear if anyone prefers one over the other and why.

2. To cut these 3/4" slots would you suggest using a 3/4" straight plunge bit that simply travels in a straight line in my jig removing around 1/4" each pass, or would you recommend instead using a 1/2" straight plunge bit traveling around the edge of the jig to cut the 3/4" slot? When doing a lot of these in succession, I'm feeling like maybe the simplicity of the 3/4" bit traveling along only one axis may be the way to go.

 

[nclemmons]

I'd go with the brass ones.  They work very well and you have a much broader selection for a lot less money.  And less storage space. 

Plus there are times when I want to use 1/4" masonite patterns and I can more easily cut the shoulder on the brass ones than on the FT ones for following a narrower pattern.

 

[Cheese]

I use both. I tend to use the Festool version when using the MFS and metric sized router bits. It makes the math easier.

Item to note for aesthetics...if you use the 1/2" diameter bit for a 3/4" wide slot, the upper & lower radiuses will not be full radiuses, there will be a small flat in them.

 

[ChuckM]

1/2" vs 3/4" -- an interesting question.

I'd use both to cut the first two slots to see if there're significant differences in their looks and efficiency, and then decide how the rest of the slots (and future slots) should be cut.

 

[RustE]

Get the Leigh 704R plate to use the typical brass bushings.

The 27mm Festool template with a 5/16” diameter bit gets real close to 3/8” (radial) difference.  Whiteside has a 5/16” diameter bit with 8mm shank.

 

[nms]

if you use the 1/2" diameter bit for a 3/4" wide slot, the upper & lower radiuses will not be full radiuses, there will be a small flat in them.

Yes. I'm open to the look of either one, but at some point but will have to try it out to find my preference.

I'm also curious as to how the Lee Valley straight plunge bit would measure up against the big (and somewhat rare) Festool 20mm spiral:

Straight Plunge Bit
Festool 20mm Spiral Bit

The Festool is an 8mm shank, while the LV is 1/4" unless I went with the 8mm non-plunge variant: Straight Cutter
Maybe the 8mm shank would provide more benefit than the plunge tip in this application when doing a lot of these slots in succession?

The Festool spiral is HSS while the LV cutters are carbide blades.

 

[Cheese]

I'd vote for a spiral cut bit every day of my life. Spiral bits have a shearing action which reduces splintering in wood by a huge margin.

I would think that they will also produce a cleaner cut in plastics. A straight bit cutter is kind of a kludge proposal from another era. Functional yes...pretty no...are there better options available...yes.

 

[Cheese]

Here's a link to a dealer for Amana router bits. These are specifically "O" flute bits designed for plastic machining. They are solid carbide bits. Page down and there is a list of plastic materials that these are recommended for.
https://www.toolstoday.com/solid-ca...flute-plastic-cutting-up-cut-router-bits.html

Here's another link for Amana solid carbide "O" flute bits that have an 8 mm shank.
https://www.toolstoday.com/cnc-rout...lastic-cutting-cnc-router-bits.html?shank=678

FWIW...I've not used a "O" flute router bit but I recently purchased one to try out in my next aluminum cutting project. They're supposed to be fantastic for aluminum & plastic machining.

 

[nms]

These are specifically "O" flute bits designed for plastic machining.

I'm not cutting plastic though. Mostly Baltic Birch and MDF. Disappointingly, I've had no luck finding spiral bits with cutters larger than their shank size made by anyone but Festool. And of course the Festool ones aren't sold anywhere in Canada. Mostly need to be ordered from Europe it seems.

I'm currently leaning toward ordering the Festool 18mm spiral, since that will fit in a common 1" guide bushing.. whereas the 20mm would not.
The 20mm cutter would have only 1mm clearance using the Festool 24/21 guide bushing, which seems like a no go. And of course the 27MM guide bushings are out of stock everywhere.. leaving no choice but to go up a size to the 30mm Festool bushing.

 

[Cheese]

These are specifically "O" flute bits designed for plastic machining.

I'm not cutting plastic though. Mostly Baltic Birch and MDF. Disappointingly, I've had no luck finding spiral bits with cutters larger than their shank size made by anyone but Festool. And of course the Festool ones aren't sold anywhere in Canada. Mostly need to be ordered from Europe it seems.

I'm currently leaning toward ordering the Festool 18mm spiral, since that will fit in a common 1" guide bushing.. whereas the 20mm would not.
The 20mm cutter would have only 1mm clearance using the Festool 24/21 guide bushing, which seems like a no go. And of course the 27MM guide bushings are out of stock everywhere.. leaving no choice but to go up a size to the 30mm Festool bushing.

I'm bad...I glanced at your photo and thought it was plexiglass because of the purple light, I now realize that it's maple/birch that's been back lit.  [embarassed]

You'll not find any solid carbide spiral router bits that have a larger cutting head than their shank. I've looked and have never found one. I believe it's because carbide is rather brittle and you run the risk of snapping off the cutter head more easily with any side load. 

 

[nms]

You'll not find any solid carbide spiral router bits that have a larger cutting head than their shank. I've looked and have never found one. I believe it's because carbide is rather brittle and you run the risk of snapping off the cutter head more easily with any side load.

Yeah the only option I've found is the Festool HSS spirals.. which end up around $80 CDN to order:
https://www.amazon.co.uk/Festool-Spiral-Groove-Cutter-Blade/dp/B003KN3TSE/

But.. if that's going to end up being head and shoulders above the LV carbide straight cutters that's what I might have to do. It's nice that they're all 8mm shanks. Really don't know why they got pulled from the NA market.

 

[Cheese]

Really don't know why they got pulled from the NA market.

A few years back Festool mixed up their router accessories. They pulled the MFS system, some of the router bits and some of the accessories for the 1010 router.  [crying] [crying]

I've ordered several Festool router bits from Amazon.de. Received them in 5-6 days.

 

[nms]

I've ordered several Festool router bits from Amazon.de.

Checked that but the only Festool spiral listing didn't ship to Canada.

Meanwhile.. I got an email back from Festool about whether the 20mm spiral would be suitable for use in their 24/21 guide bushing:

"Item 486031 is large enough to house a 20mm cutter as it is slightly larger than 21mm ID. This combination will work just fine."

From what I gather, there would be around 1.7mm of clearance between the cutter and bushing. Is that really nothing to worry about? I wonder if any negative impact on dust collection. Seems usually people try to aim for a bushing ID that is .25" larger than the cutter don't they?

This guide bushing business is completely new territory for me.

 

[RustE]

1.7 mm or ~0.066 inch on a diameter is not in my comfort zone for a wood router.  My concern is chips getting between the two and causing more problems. The lowest I would think of going is 0.125 inch on a diameter.

 

[Cheese]

Meanwhile.. I got an email back from Festool about whether the 20mm spiral would be suitable for use in their 24/21 guide bushing:

"Item 486031 is large enough to house a 20mm cutter as it is slightly larger than 21mm ID. This combination will work just fine."

Well if you think about it, the router bits are centerlesss ground so they will have a run-out of probably .001" or less. Add in the runout you expect to see from the router, and you will arrive at the total runout IF if they are both in the same direction. If not, they will offset each other by some number depending upon their alignment.

I'd not be hesitant about using this combination, however I would be careful to center the guide bushing in the router. Check it once...check it twice...the numbers are in your favor

 

[nms]

I think I'm going to pass on the 20mm Festool HS spiral. It's probably just going to dull cutting slots in MDF & BB.

You'll not find any solid carbide spiral router bits that have a larger cutting head than their shank. I've looked and have never found one.

There are these bad boys, but 1/2" shank and $$$$$.

For 8mm shank spiral carbide bits the largest I've found is the Festool 10mm:https://www.festoolproducts.com/festool-490980-spiral-bit-hw-10x30mm.html