Router Speeds

[DW]

I have a Ryobi 1 3/4 hp variable speed plunge router mounted on my BT3100 and have been having a problem with the work piece "skipping" forward while making a pass. Can the speed of the router effect this? What speeds are suggested for what type of bits? Wood hardness? Depth of cut?
In short, why is the router variable speed?

Thanks for all the great ideas found here,

Dave

[RodKirby]

Facing the fence, move the work piece from right to left. It sounds like you're going left to right (the wrong way).
This talks about speeds and a whole lot more...

http://www.newwoodworker.com/rtrbitspds.html

[DW]

Rod,
The wrong way idea was one of the first I explored. Oddly enough the problem was less severe going from left to right.... Go figure.

Thanks for the link, great info.

Dave

[leehljp]

Dave,

You do not, by chance, have the set up with board passing between the router bit and fence do you? If so . . . Very dangerous!

As to speeds, larger diameter bits need to spin at a slower speed, hence the need for variable speed. The outside of a 2 or 2 1/2 inch bit is traveling at a considerably faster speed than say a 1 /2 dado bit or round over type of bit. The excess speed could be dangerous, cause the wood to burn, dull the blade quicker, etc.

A second thought, with the router mounted on the BT, a few people have had problems with their mounted router and minor vibration. There is a small clamp that clamps the table to the rear rail rather than letting the tabs fit into the slot. This is necessary or the table will wander a bit. This minute vibration and table wander can be causing your problem.

[Kristofor]

quote:Originally posted by DW

Rod,
The wrong way idea was one of the first I explored. Oddly enough the problem was less severe going from left to right.... Go figure.

Thanks for the link, great info.

Dave

Is the bit recessed in the fence or out from it? Unless it's out and exposing the "back" of the bit, I'm not sure how it would be pulling more when cutting right to left than when climb cutting.

Do you have any more detail on what "skipping" entails?

The variable speed allows for a roughly constant cutting surface speed between large diameter bits and smaller ones.

Kristofor.

Edit: Timing is everything, stop to take the dog out and look like a goofball echoing the previous poster [)]

[RayintheUK]

quote:Originally posted by DW

.......... have been having a problem with the work piece "skipping" forward while making a pass. Can the speed of the router effect this? What speeds are suggested for what type of bits? Wood hardness? Depth of cut? In short, why is the router variable speed?

Dave,

The symptoms you describe concern me, as it seems - as others have suggested - that you are passing the workpiece between the fence and the bit. This is VERY DANGEROUS and has a high likelihood of jettisoning the workpiece at high speed! It also exposes the entire cutter, with the attendant potential of serious injury. As the cutter will be rotating anti-clockwise when used inverted in a table, that would explain why "the problem was less severe" in your case when passing from left to right, if you are working as described.

I hope the following plan view simple diagrams (not to scale) may make things clearer:



For other routing tips and safety methods, please read this link.

HTH

Ray.

[leapfrog]

Great info Ray, thank you for posting it. Being a newbe myself I'm always looking for tips and safety advice. Could this be posted somewhere on the site so we (I) could have easy acess to it (the article).
Thanks again.

[monte]

Great post Ray!

[LarryG]

The reason the setup in Ray's second illustration is dangerous is because the feed direction is now backwards. The bit's rotation will try to both propel the workpiece forward and pull it away from the fence. When a setup like this is necessary, as it occasionally is, the feed direction must be reversed.

[JimD]

Mark,

I think your main question has been answered but I didn't see a lot on your original question about speeds so I will comment. The only time I slow the speed of my routers down is when using the very largest bits. These have diameters of 3 inches or a bit more (up to 3 1/2). Up to about 2 inches, I leave the speed control alone. With the largest bits, I reduce the speed to about half. This is typically occurring in my router table which has an old single speed Ryobi R-500 with a separate add-on speed control. What I do is set the speed to the minimum (bit doesn't turn) and then increase it to where it sounds right. Not very scientific but it's typically about half the scale so I am assuming that is 1/2 the speed - gross assumption. That also results in acceptable cutting performance. I think the principal of reducing speed over about 2 inch diameter is something to consider and also the thought of going to the minimum speed and increasing as necessary to get reasonable performance. You definitely do not want to spin a 3 1/2 inch bit at 25,000-30,000 rpm. I wouldn't want to be in the same room. It could come apart on it's own and would be very susceptible to damage as you tried to cut.

For most bits, the speed control is not necessary, IMHO. On the ones where it is necessary, however, I think it is vital.

Jim

[DW]

Hank et al,
First, I am not passing the workpiece between the blade and the fence as shown in diagram #2 above.

Second, until now I had not taken the time to look at the direction the router bit spun (the router table side just does not get that much use in my humble attempts to make sawdust) and had assumed the direction of feed was the same as the TS. Looking at the picture above and noticing his arrows were not the same as my arrows led to the simple answer. Feeding the wrong way, operator error as usual. Skipping was caused by the bit pulling the workpiece forward instead of cutting against the direction of feed.

RodKirby,
Thanks for the help, now I've got it. As above, I always just assumed it fed the same direction as the TS.

Hank,
Could you build on the rear clamp you mentioned above. My table has a built-in clamp on the front rail, but nothing on the back. Is your clamp an add-on?

Thanks all for the great info.

Dave

[LarryG]

quote:Originally posted by DW

Now the only question (on this topic) I have left is whether RodKirby made a typo when he said feed Left to Right?

I think you must've read that wrong. He says to feed from right to left, and that feeding left to right is "the wrong way."

Of course, he DOES live in that other hemisphere ...

Seriously: on a table, RIGHT TO LEFT is correct MOST of the time. There are exceptions ... when you're widening a slot, and the second pass is on the side of the slot furtherest away from the fence ... or as I mentioned, those times when it is necessary to run the workpiece between the fence and bit. Otherwise, RIGHT TO LEFT.

[leehljp]

Dave,

I don't use the router on my saw because I have a dedicated router table. The situation with the clamp has been posted a couple of times before; I don't remember when or where it has been posted. I think the clamp came with the accessory kit.
Part number # 4080330 - Accessory Table Clamp

[Pappy]

Dave, here is a picture/diagram of a 'home brew' table clamp. I think I got this from Lee (My appologies to the originator if my memory is wrong.

[Fat Casper]

DW-
Thanks for asking. That's what I love about this place. I'm so new that I haven't gotten to use my router table yet, but I'm a lefty and used to doing things that seem a little odd to me. I saw exactly what you meant by assuming the feed direction was the same as for the saw.

Great question. You helped more than just yourself.