Before I fall into the Tim "The Tool Man" Taylor I thought I would ask here.

 

My router has variable speed. Does anyone have a good formula or memory jogger as to when to use which speed?

 

I did a little round over work this past weekend and discovered all the cuts with the grain were smooth and crisp and all the across the grain cuts were burnt.

 

Maybe it's the operator's head-space and timing issue.

Edited November 24, 20178 yr by Ron Dudelston
tags added

Just a quick hit and run comment here ACR, cuz I gotta run, but the larger diameter the router bit, the slower the speed. The smaller diameter router bit, higher speed. For general small bit for profiling etc, you can max out that speed, it's when you start getting into the larger wing cutters for raised paneling and such, you'll have to follow the recommended speed range from the manufacturer of the wing cutter or panel bit.

This is just a generalization of course, others will have a more specific answer I am sure.

By the way, nice signature.

One more thing, feed rate should be moderate and sharp for that end grain, it will burn easily. Specially with certain species of wood, what species of wood were you using?

2 minutes ago, John Morris said:

Specially with certain species of wood, what species of wood were you using?

 

Poplar

 

PS: I were a warrant officer, watch this.

Like John said, bity diameter is pretty crucial but poplar is pretty forgiving.  With poplar, you can keep a pretty high speed unless the bit is huge.

1 minute ago, Ron Dudelston said:

unless the bit is huge.

 

1/8th inch roundover bit.

9 minutes ago, ACR_SCOUT said:

 

1/8th inch roundover bit.

That small of a roundover can take a lot of speed.  With that small of a bit and a high speed, move the rougter along the piece at rate of speed because it might burn.

Just now, Ron Dudelston said:

That small of a roundover can take a lot of speed.  With that small of a bit and a high speed, move the rougter along the piece at rate of speed because it might burn.

 

So, it is operator headspace and timing.

 

I guess it is a technique I'll have to learn through experience.

 

5 minutes ago, ACR_SCOUT said:

 

So, it is operator headspace and timing.

 

I guess it is a technique I'll have to learn through experience.

 

Pretty much.  If you have a piece of scrap you'll get the feel for it in a snap.  I have faith in you!  Luckily, it isn't cherry because it burns easily.

 

Clean ans sharp bit really help.

1 minute ago, lew said:

Clean ans sharp bit really help.

 

Brand spanking new bit, right out of the box, chucked up in a router table.

 

I just gotta figure out the technique.

12 minutes ago, ACR_SCOUT said:

 

Brand spanking new bit, right out of the box, chucked up in a router table.

 

I just gotta figure out the technique.

Well that eliminates that! Faster travel of work should fix the problem. I still haven't figured out how to completely avoid burning on cherry and maple. 

 

One trick you can use is to make the first pass to remove ALMOST all of the material then raise the bit  a fraction and make a skim cut to remove the remainder. The small amount of material removed in the final pass won't build up as much heat and reduces the burning. For removing the burn marks, I've stopped using sandpaper and started using scrapers. Cheaper and a little easier to control how much (and where) material is removed.

The router table is a great tool but, in my experience, hand held would be better for the end grain operation. It may be just my trepidationess but, I tend to go slower on the table. And, burning is likely a function of feed rate. 

As Lew said, the scraper is your friend, too.

Edited December 12, 20169 yr by Gene Howe

Can we assume you are (safely) using a miter fence or backing board to profile the end-grain...?

Also, rout your end grain first, then the long grain. This way if you have tear out at the ends the long grain routing will eliminate the tear out.

On 12/12/2016 at 9:39 AM, lew said:

One trick you can use is to make the first pass to remove ALMOST all of the material then raise the bit  a fraction and make a skim cut to remove the remainder. The small amount of material removed in the final pass won't build up as much heat and reduces the burning.

 

I have heard the exact opposite.   I don't recall if it was from one of the equipment manufacturers (maybe Bosch) or from the owner of a commercial cabinet company that does most everything on CNC machines.   The theory is that smaller chips (dust) don't pull away the heat as well as a larger chip.  

 

That said, I don't know, but I'd change the feed rate.

7 minutes ago, kmealy said:

 

I have heard the exact opposite.   I don't recall if it was from one of the equipment manufacturers (maybe Bosch) or from the owner of a commercial cabinet company that does most everything on CNC machines.   The theory is that smaller chips (dust) don't pull away the heat as well as a larger chip.  

 

That said, I don't know, but I'd change the feed rate.

That is very possible. I picked this tip from the Woodsmith Shop program. May be a function of router speed vs. CNC speeds.

On 12/12/2016 at 1:57 PM, Nickp said:

Can we assume you are (safely) using a miter fence or backing board to profile the end-grain...?

 

You may assume that but I am just using a bearing roundover bit. I don't think I can use a fence with a bearing bit. Maybe I can but just have not figured it out.

On 12/13/2016 at 8:05 AM, John Morris said:

Also, rout your end grain first, then the long grain. This way if you have tear out at the ends the long grain routing will eliminate the tear out.

 

Thanks John, I did figure that one out but I was a little slow on the uptake, it took about 6 tearouts before I figured it out.

13 minutes ago, ACR_SCOUT said:

it took about 6 tearouts before I figured it out.

That's the best way to figure out my friend!