router bit speed

[Sawatzky]

I have read a lot about speed settings and varible speed. I just got a PC 690, single speed. I ordered some Freud bits for it, all of which are 1 1/2 inches wide. The manual for the router says not to exceed 2 1/8 inches, so can I run these bits without any problems at full speed? Also, can I run a 1 5/8 rail and stile bit on this router? That is about the maximum width I will ever use. I just want to make sure these size bits can run at full speed. Thanks.

[monte]

Here is a link to a speed chart for router bits. I would stay within these guidelines.
http://www.newwoodworker.com/ref/rtrbtspds.html
Tom also has a lot of other information on his website.

[LarryG]

Those bits are all too big too safely run wide open, IMO. The 690 is a fine router but you might want to exchange it for a VS model, if you still can, or if not get an aftermarket speed control for it.

[Sawatzky]

Does an external router speed controller do the same thing as an internal one? Will I have loss of power, and how will I know what RPM I am setting it at?

[Wood_workur]

You know what rpm setting you are at with a little math. If you know your router spins at 23k, and the variable speed is from 0 to 100%, then 1/2 is equal to 12.5k, and 3/4 is equal to 17250. It is similar to an internal var. speed controller, the only difference being it can damage the router with extended use, so use only when you need it.

You could have a losss of power because on internal var. speed controllers (the good ones), the motor is kep at that speed under load, but with a external var. speed the motor is supplied with the same amount of electricty no matter what.

[tribalwind]

quote:Originally posted by Sawatzky

Does an external router speed controller do the same thing as an internal one? Will I have loss of power, and how will I know what RPM I am setting it at?

i'd love to know the answer to this as well...
i take issue with not being able to use an add-on speed control with my m12v router when mounted in the table..

[Sawatzky]

Just curious, why is a variable speed control unit bad for a router?

[tribalwind]

quote:Originally posted by Sawatzky

Just curious, why is a variable speed control unit bad for a router?

they it's bad to use with routers that are already VS...
can burn it out somehow,

[vaking]

When external speed controller works - it works without loss of power. It is similar to a dimmer switch on a lamp curcuit. The unfortunate part is that it works on simple routers only. Simple routers are those without built-in sophisticated electronics curcuits. Most modern routers now have features like soft start, speed stabilization, etc. Those features require built-in electronics and they will interfere with external speed control. Older routers were simpler and external speed controls work fine on those. PC 690 is an old model, external speed control might work on it. Most likely people here already know answer to that - it is a popular router. In my shop external speed control works on Rotozip (my trim router) but does not work Hitachi KM12SC because the latter has soft start and speed stabiliizer. I also have M12V in a table but M12V has an internal speed control, I don't see the point of even trying external control with it.

[tribalwind]

thanks alex for ellaborating on this
re: external with the m12v, its just easier to reach a control mounted to the side of the table next to external power-switch,rather than reaching inside the table..maybe i just need to redesign my table to accomodate the router..

[rfisher7381]

Does anyone use any type of photo tachometer or other method to measure the speed of their router bit? Anyone see any need for this? I guess I haven't worried to much but then I read in the forums about maximum speed for bits and I don't want to exceed that. I have a Hitachi M12v router but I don't know what the dial readout translates into router rpm's. Thanks.

[JimD]

I have a PC690 with variable speed and one without as well as a Ryobi 500 without variable speed. I use an add-on controller with the single speed 690 and the Ryobi but only when using bits bigger than the cope and stick bits. I run those full speed and it has never given me a problem. I typically used a stacked cutter so it is pretty tall. If you want to be plenty safe I would get an variable speed controller and try it and see if you like it. I've had good luck without one until I get to the panel raising bits and the like.

I don't worry about exactly how fast the bit is going. When you put in one of the 3 inch plus panel raising bits just slow it down to the point where you don't want to leave the room. More seriously, I turn it down to where the bit doesn't turn, start up there, and increase speed to the point where it is obviously moving pretty good but at much less than full speed. The scale on the controller would say around half speed. That also seems roughtly consistent with the charts.

My personal rule is anything much over 1 1/2 inches diameter with height also factored in (taller is riskier to run flat out) you start thinking about a speed control. Weight is another factor - something like a crown moulding bit that is heavy is riskier to run fast than a cope and stick bit that is not removing material it's entire length and is therefore lighter.


Jim