22.5 Degree Chamfer

[morpheus83uk]

Hello,

I have recently purchased on of the below bits for cutting lots of 22.5 degree angles:

https://www.routerbitworld.com/CMT-857-502-11-1-1-4-Diameter-22-5-Degree-Chamfe-p/cmt 857.502.11.htm

I am using 18mm pine wood however I need the chamfer to be the entire length of the wood. I know the bearing is supposed to go along the wood but when I try to do this I end up with a lip at the top (obviously) is there a way of doing what I need with this bit? I am going to be building quite a few octagonal tunnels and I figured that using this would make life quicker and easier. However no matter what I try with a fence or without I cant seem to get it to do what I need.

I am doing something fundamentally wrong but I cant figure out what.

Any help with this is appreciated.

James

 

[Deleted member 174758]

1. Start off with timber which is a little longer than the final length you need, say 19in when you actually need 18in, then trim to length after you've finished machining the edge profile, removing the gouged end pieces

2. Machine the edge profile on a very long piece of timber, say 8ft long, then again trim the ends and crosscut your required lengths out of the longer piece.

In both cases try to increase the feed rate as you exit the cut in order to get more control and stability

There is a method where a climb cut is used but TBH you don't sound as though you have sufficient experience or control of the router to handle this just yet

 

[morpheus83uk]

Thanks i had a look on YouTube and a guy has a piece of wood on top of the wood to be cut which slides across the bearing, would this work as well?

I will still try your methods mentioned above I am just looking for others ways so I can try them and find what works for me.

Also what kind of speed should the bit be rotating at? As I am wondering if I need to increase or decrease the speed as I am currently set on about 3 or 4.

Thanks

James

 

[Doggit]

You don't say what the highest speed is, but a faster speed can give a cleaner cut.

A router table is another option (about £30 from Aldis when they have them) but you haven't mentioned how long your wood pieces are, and whether they are already cut to length. You could set up a piece of wood so that the router stops against it rather than using the bearing as a guide.

 

[morpheus83uk]

Sorry the wood is 30cm in length which is the length they will be. I don't know what the fastest speed is without looking in the manual.

When you say set up some wood so the router stops up against it I am unsure what you mean?

Thanks

James

 

[Doggit]

If you're setting it to 3 or 4, do I assume the highest number is 5 then; if so, 4 would be about right. You're using the bearing as a guide, but if you push the wood up against a piece of wood the same height as the wood you routing, and then placed a piece of wood against the back of the router base, then you've got a secondary guide to work from when you get to the end of the wood you're routing.

 

[morpheus83uk]

I think the highest setting is around 8 or 9. So I should be using it at a much higher speed? Like 7?

So if I understand you correctly I have my guide setup and I go across it like usual but have another piece at the height of my cutting piece so it's guiding the height as well? Which in effect negates the bearing?

Thanks

James

 

[Doggit]

No, because you've already got the pieces cut to length, you get to the end, and effectively round off the corner becasue the bearing has nothing to guide it. Actually, I've just thought that if you have the next piece in place, then you don't get the problem; and when you get to the last piece, put the first one there to continue the process.

As to speed; if the speed is too slow, then it won't cut cleanly, but if it's too fast, then it can burn the wood. Sometiles you just need to experiment a bit.

 

[Roger928]

I am using 18mm pine wood

Clamp on another piece of 18mm timber or suitable straight edge for the bearing to run on.
Would be best to trim the angle on a table saw then finish with the router bit.
An accurate machine with a fine sizing blade would render the router redundant.