[Glidergider]

I've got a newbe question for you. What are the traits of Climb vs Conventional cutting? These are options on my CNC CAM program.

Which gives me the smoothest edge, and why would I choose the other method?

[ger21]

When cutting wood, conventional cutting will almost always give a better cut. The only time I climb cut is when the cutter breaks the edge of the workpiece, and tearout is a problem.

[Al_The_Man]

Another thing to consider when climb milling, problems arise if backlash is present as the cutter tends to pull the table into the tool.
Al.

[Glidergider]

Thanks guys for helping this rookie out with the details of cutter rotation.

[Adam M.]

I am going to disagree with Ger a litle bit. Climbcutting is great on the long grain, especially where chipout presents a problem, but leaves endgrain feeling a bit fuzzy. When running moldings and doors components through the shaper, I always climb cut. But, it is not as efficient as feeding into the wood. If doing surface type machining on a CNC, as a rule of thumb, always feed into the work piece.

[RoboArmBuilder]

What exactly is climb cutting?

I've got so much to learn!

Dan

[HuFlungDung]

Climb cutting is when the tool wants to grab the work and huck it across the shop. You know, the warning on the radial arm saw that says "Do not rip from this end"? That's the end we cut from when climb cutting. All onlookers are advised to 'climb to safety'

[bp092]

I am going to disagree with Ger a litle bit. Climbcutting is great on the long grain, especially where chipout presents a problem, but leaves endgrain feeling a bit fuzzy. When running moldings and doors components through the shaper, I always climb cut. But, it is not as efficient as feeding into the wood. If doing surface type machining on a CNC, as a rule of thumb, always feed into the work piece.

You climb cut on a shaper? Are you crazy? Only time I would ever climb cut is with a router, manually and sometimes I do it to relieve the exposed edges of frames, glass doors etc. I take about an 1/8th to a 1/4" inch off climb cut, then run conventionally (left to right) for the rest of the meat. And I only do this with woods that chip out, like oak for example. I've heard of a lot of people losing fingers climb cutting on shapers before. I wouldn't ever do it, not even with a power feed.

[Adam M.]

Whoa, hold on. I have a pretty sizable shaper and power feed. My fingers don't get within 3 feet of the cutter. As most professional woodworkers will tell you, there is nothing wrong or inherently dangerous about climb cutting on a shaper with a power feed. I don't understand what you think is so dangerous.

[bp092]

Whoa, hold on. I have a pretty sizable shaper and power feed. My fingers don't get within 3 feet of the cutter. As most professional woodworkers will tell you, there is nothing wrong or inherently dangerous about climb cutting on a shaper with a power feed. I don't understand what you think is so dangerous.

Because I've seen people lose fingers doing it. It's perfectly fine to do, and it works. But if you aren't paying attention and using really sharp cuttings and your power feed can't handle the feed climb cutting will push at times, then you can really get yourself or someone else hurt. In a controlled situation it's fine. But you won't catch me doing it. And I don't think its really all that necessary if you have a good set of cutters to get a nice finish cut.

[Adam M.]

I really don't want to beat a dead horse here. I know what you are saying about not paying attention, but I wanted to respond to your point about a good set of cutters making climb cutting needless. There are some woods that, no matter how sharp your cutters, chip out. When running door frame material, I climb cut everything so as not to worry about chipping. Mahogany and maple are two good examples of wood that can chip, no matter how careful you are. That's all I wanted to say. You would never catch me climb cutting anything where there is a significant amount of material being removed.

[ImanCarrot]

Deleted by myself- explained Climb and Conventional metal machining in a wood forum. My bad! soz... can only blame lack of caffine and nicotine!

Iain.

[Oldmanandhistoy]

A lot of years ago now while working for a furniture manufacturer I was a bystander to a double injury. A new employee decided he would hand feed some timber the wrong way (climb cutting) on an overhead industrial router. Within the blink of an eye he severally damaged three fingers and the timber travelling at high speed broke the arm of someone working close by. He was very quickly down graded to a labour.

I would advise looking to reducing the cutting angle on your tooling where possible to reduce tear out before considering climb cutting. I have done this many time using an oil stone adding a secondary cutting angle. I am a qualified wood machinist by trade and in 25 years have never needed to use climb cutting.

John

P.S.
Please note the picture linked to is related to metal milling machines.

[ImanCarrot]

Old is correct- those pics refer to metal cutting. I'm an idiot and didn't notice this was a wood forum thingy- was just checking "New Posts" while my machine goes through tedious 15 min cycles.

My sincere apologies for any confusion caused. I shall delete the link.

Respect!

Iain.

[Oldmanandhistoy]

Old is correct- those pics refer to metal cutting. I'm an idiot and didn't notice this was a wood forum thingy- was just checking "New Posts" while my machine goes through tedious 15 min cycles.

My sincere apologies for any confusion caused. I shall delete the link.

Respect!

Iain.

The picture is fine for demonstrating the difference in climb/ conventional cutting. I just know climb milling is used to good effect on metal milling machines.

John

[Ed_R]

Imagine looking at a router bit from above as it as it spins clockwise. If you feed the workpiece into teh bit on the RIGHT side, you are conventional cutting, and you'll note you have to push the workpiece into the bit. If you feed the workpiece into the bit on the LEFT side, the bit will grab the workpiece and want to take it from you and hurl it across the room - unless there's something to prevent it, like a strong power feeder.
In CNC terms, the biggest area where climb and conventional cutting make a difference, from my observation, is that the machine ( and the router and the bit and everything else ) flexes in a different direction than it does when you climb-cut. People can talk all they want about how their machine doesn't flex and this and that, but most routers will fall victim to bit deflection in their weakest links- the chucks. You can find some significant deflection differences in the very same cuts by making one of each and physically comparing them.

From what I've seen, it makes less difference in straight cuts than it does in curved ones.

[neilw20]

I've got a newbe question for you. What are the traits of Climb vs Conventional cutting? These are options on my CNC CAM program.

Which gives me the smoothest edge, and why would I choose the other method?

Climb milling works well on most metals. Improves tool life quite a lot too. I have found it works quite poorly on acrylic. I think it depends a lot on the material, and a few test passes will show which works best. On metal it is usually better, but on other materials, the rubbing action of not climb milling helps to burnish the surface. Also depends on how well the swarf is being cleared away from the cutter. Climb milling is futile if there is any free play in the feed system.

[ImanCarrot]

I have found it works quite poorly on acrylic

Spot on, the initial "grab" cut on Climb milling with acrylic actualy melts the surface. It solidifies a fraction of a second later with contaminants from air/ coolant. Oh well.. basicaly crazing cos of thermal shock.

With acrylic and other polymers there is a fine distinction between cutting to deep and too shallow.. luckilly I got it sussed

Nice Optical finish????

[Chuckie]

I've got a newbe question for you. What are the traits of Climb vs Conventional cutting? These are options on my CNC CAM program.

Which gives me the smoothest edge, and why would I choose the other method?

I see you getting a lot of action on the question but here is the rule of thumb. If its Natural, Climb Cut (hard woods. cedar, any type of solid wood) but if it's man made like plywood, fiber board, foam, plastics, then conventional cut. But (there is always one of those) it's only the rule of thumb and not the rule of law. Remember this though wood will most likely bust out and chip if the tool exists the cut. I some times have to lay a piece of scrap wood where the tool comes out in order to prevent that. Wood is fun to cut but it always tests ya.

[Chuckie]

What exactly is climb cutting?

I've got so much to learn!

Dan

Here is your answer Dan.

Looking down at your part on the table if you program the tool to go clockwise around your part you are CLIMB CUTTING.

If you program your Tool to go Counterwise around the part then you are CONVENTIONAL CUTTING.

If you are cutting just the side or the end it doesn't matter. The rule still applies.

Just imagine the Tool going all the way around but just apply it to the side or end.

Too simple HUH ?