Quick and accurate method for cutting mitred edges?

[rjb]

I use a CNC router to cut out parts for model kits from 6mm & 9mm MDF. The CNC cuts the parts out very accurately, but some parts need to have mitred edges (mainly 22.5, 45 or 60 degrees). Although it would be possible to cut the mitres with the CNC it’s not really practical as it would mean having a cutter for each angle and manually changing the cutter and re-setting the machine for each mitre. I currently use a bandsaw to trim the angles on the mitred edges, but it’s a bit fiddly and I find it difficult to cut them as accurately as I’d like because many of the parts are quite small and irregular shapes. As this is a job which I undertake frequently I’d like to find a better / easier method and I was thinking about making some kind of jig to use on a router table. I’d appreciate any suggestions..

Thanks,

Richard.

 

[jasonB]

Use a bearing guided cutter like these, keep one of your components as the template, fix another to it and route the edge to the required angle. The bearing will run against the template so the whole edge of teh work can be mitred

Jason

 

[wizer]

I would also recommend you stick with router bits. After the tooling cost, changing the bit in the CNC can't be too much bother?

 

[Digit]

I was about to say exactly the same as Jason. But how large are the parts on second thoughts?

Roy.

 

[rjb]

Thanks for all replies. I have used a 45 degree bearing guided cutter, but so far haven't been able to find a 67.5 degree one with 1/4" shank and this is the largest size my CNC and router table can take. For this reason I was thinking about making some kind of jig to present the workpiece to a straight trimmer at the appropriate angle, but I'm not sure if this would be very easy or practical and your suggestion of using the appropriate cutters does sound like a far better approach. The question now is does anyone know where I can buy a 67.5 degree cutter with 1/4" shank or do I need to buy a router with 1/2" collet?

Thanks,

Richard.

 

[JonnyD]

trend do one http://www.trend-uk.com/en/UK/product/1 ... utter.html

cheers

jon

 

[rjb]

Thanks very much for that.

Richard.

 

[wizer]

I'd be surprised if Titman Tip Tools didn't do one. I assume you can't find one on Wealden's website? Might be worth a call. They are very good and easy to talk to IME

 

[ondablade]

I don't know how accurate this device for setting stock mitre gauges is, and it would for sure depend on how good the fit of gauge bar is in both the slot in your saw table, and in the device.

Given the fairly close spacing of the dowel pins it seems like it could work well on smaller mitres not requiring extreme accuracy:

It gets good press in the US, and is not expensive: http://miterset.home.comcast.net/~miterset/index.html#