HELP! Problems with tear out.

[relic_hunter]

Here’s my problem; I have many of the pieces pictured below to cut. Many of the corners are tearing out making them unusable. If you know how I can eliminate this problem I would greatly appreciate your assistance!

I have used a straight .25 end mill and an up-cut spiral bit. I have tried running at one and two inches per sec. Cut depths of .25 and .125 inches. The slower speeds have helped somewhat but the problem remains. Any Ideas?

http://i211.photobucket.com/albums/bb229/woodworks_az/IMG_6728.jpg

http://i211.photobucket.com/albums/bb229/woodworks_az/IMG_6726.jpg

http://i211.photobucket.com/albums/bb229/woodworks_az/IMG_6729.jpg


http://i211.photobucket.com/albums/bb229/woodworks_az/IMG_6727.jpg

[knight_toolworks]

you want a downcut bit. it's all I use for solid woods. also don't do a climb cut it will cause that problem too.

[ken_rychlik]

Sounds backwards steve. A climb cut should fix it.

Run the profile in Climb and leave a skin on the bottom of about .020
Then run conventional to cut it loose the rest of the way.

[dlcw]

First thought would be to complete the milling operations on the smaller arches first then mill the longer arches.

This is kinda like doing a raised panel door - you first mill across the end grain then mill with the grain. Any chipout is removed when you cut with the grain.

I would also look into a downcut spiral bit for this type of work as it will shear the wood more so then cutting the wood. Should get cleaner milling operations.

[ken_rychlik]

Chuck,

What direction were you running (climb/conv) and did you do the parts in one pass or several?

[relic_hunter]

I was doing a climb cut making three (.25 per pass) passes to a depth of .8125.
Thank you all for your quick response!

[Gary Campbell]

Chuck...
This appears to be a double posting. If you post only once, all the responses will be in a single thread.

[knight_toolworks]

Sounds backwards steve. A climb cut should fix it.

Run the profile in Climb and leave a skin on the bottom of about .020
Then run conventional to cut it loose the rest of the way.

well you can be right and wrong. it depends on the cut and the wood. but when I changed cutting my hand planes to a climb and a regular cut as a cleanup I started getting tearout for the first time since I started using downcuts.
But for the most part downcut bits have eliminated tearout in solid woods for me. I also cut at 1ips and 1/2" cut depth.

[beacon14]

What size blank are you starting with? Don's suggestion is the one I was going to make. If you cut the end grain after the edge grain it will be much more likely to tear out.

You may have to make a custom toolpath that cuts the ends first, then the sides, instead of just doing a profile cut around the perimeter.

[ken_rychlik]

I normally get tearout on conv cuts, and thus the reason for going to climb. I can see where this may not always be the case. I've never built a hand plane.:rolleyes:

It won't hurt to reverse what he is doing and try it.

Also you can go into node editing and make different start points. This would tie into what Don was talking about. Cut the end grain first, no matter your cut direction and it should help. It works on raised panel doors and it can't hurt.

Downcuts have not made much of a difference for me. Sharp straight bits have been treating me well.

[knight_toolworks]

here is what I have cut no tearout. 1ips centurion downcut 8k rpm .5 pass depth. A roughing bit can do a good job but they are very expensive.
http://i154.photobucket.com/albums/s266/knighttoolworks/plane%20kits/razeejackkit.jpg

[ken_rychlik]

Steve, what confuses me is that you are running a cnc to make a plane to get back to the basics of woodworking. :p

Good hold down is important.

Another thought is the type of wood and moisture content could be affecting the end result. A hard wood with to little moisture will spit on you very quickly.

[knight_toolworks]

Steve, what confuses me is that you are running a cnc to make a plane to get back to the basics of woodworking. :p

Good hold down is important.

Another thought is the type of wood and moisture content could be affecting the end result. A hard wood with to little moisture will spit on you very quickly.

got me there. but by the time I worked the bugs out of the process I only sell kits. I didn ot even know I could make a plane on the bot till an engineer told me.