Router Help.

[ozzpoz]

I'm looking into doing some template routing, I'll be using a router table and I'm a bit confused with which bit to get. Straight, up cut , down cut , spiral , compression.
Should I have bearing on top or the bottom. Does the template go on top or bottom.

I've seen this one on Amazon that seems to be a combination or everything. Probably not best quality but once I know what I'm doing and if it's something I do more of I can get better. ( Sorry if not allowed links )

Just need a head up which type to use.
Thanks.

https://amzn.eu/d/aFqA484

 

[Gordon Tarling]

Well, the bearing has to run against the template, so that solves that question. Template top or bottom? I guess that largely depends on how you're able to attach the template to the workpiece. I've always worked on the principle that the side the cutter is cutting away from should be the 'good' side, so choose according to that. I've not yet tried the up and down type of cutter, perhaps someone else has experience?

 

[Sideways]

Me, I'd default to putting the template on top so the router base scrapes over that, not the workpiece, and you can see where you are going.
Template on top and you don't necessarily need a bearing guided cutter, you can use a guide bush. The tempate is just made undersize by an allowance equal to the difference in size between the bush and the chosen cutter. You may not want to do this for a complex shape but if the template is simple and primarily to prevent any chance of a mistake that could happen when hand routing, it's not a big deal.

Either way, having the template close to the router is a little more stable, so template on top if you are handholding the router above and template on the bottom if you are template routing on a router table.

Upcut bits clear the chips from a narrow slot best but don't leave the best edge of whichever surface is upper. They are good for the lower face if you are cutting right through the board.

Downcut bits give the better edge but don't clear chips well in narrow slots.

A standard straight cut bit will be cheapest / easiest / default unless you are buying one of the two above for a reason, and that reason will often be to use on laminated sheets.

I find larger diameter bits cut better than narrow ones, so wherever I can I like a larger diameter cutter. 16-20mm is my most used on a 1/4" router. Likewise, shorter cutters are stiffer so avoid using long ones unless you absolutely have to.