How long does it take you to mill a slab (cutting time)

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Rico_Pendejo

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I’m curious how long it takes everyone to mill a slab. I was milling some white oak the other day, 30” wide on one end, most was between 20-24”, and 9’ long. The first few cuts seemed really slow (30 minutes or so), so I kept filing the rakers down a bit at a time, and managed to get it down to about 15 minutes.

I’m using a 395xp with a 36” bar. It feels like it’s cutting well, but I don’t have a good reference for what well is.
 
That seems very slow. I use a stock 395XP with a 36" bar as well. I can make the same cut in oak or pecan in less than 5 minutes. I use woodland Pro 33rp chain. Sounds like you might have a chain problem.
 
10-15 minutes depending on the grain also. With a 36" bar on a 7910. I use a Oregon ripping chain.
I do not think it differs the speed much. But it is mainly for the finish.

Just the thought a bandmill would do it in minutes and doesn't need to take 5mm but just 1,1mm per cut, makes it feel much longer.


Verstuurd vanaf mijn SM-G955F met Tapatalk
 
I’m curious how long it takes everyone to mill a slab. I was milling some white oak the other day, 30” wide on one end, most was between 20-24”, and 9’ long. The first few cuts seemed really slow (30 minutes or so), so I kept filing the rakers down a bit at a time, and managed to get it down to about 15 minutes..

It sounds like you need to find out about progressive raker setting, look through the Milling 101 sticky.
 
It sounds like you need to find out about progressive raker setting, look through the Milling 101 sticky.

I've been lurking for the past few months reading through the Milling 101 sticky, its been a great help. I measured the angle on my rakers and its 7.5 degrees. How much does the shape of the raker have to do with it? Ive just been filing them down so they are flat on top, does having a 'shark fin' shape help?

IMG_1180.jpg IMG_1176.jpg
 
Just in case newbies are reading this, the "Raker angle" I'm referring to in this post is not the angle on the top of the raker. It's the angle between the cutter tip and the first point of contact the raker is likely to make with the wood relative to the top of the bar. Its the angle in red in the second photo.

It looks like you have plenty of raker angle.

This one has a raker angle of 8.1º (angle of red line to the bar top) but raker has a flat top so raker and cutter won't penetrate as far as the angle would suggest.
Chaina.jpg
This one has a raker angle of 8.6º and looks like it has a little bit of rounding on the top of the raker ,so based on both the angle and rounding it should penetrate further.
What concerns me a little is the tips/edges of some of the cutters look slight rounded - see red arrow. It could be just the angle of the photo or the presence of a bit of dirt but these must be have no rounding.
Can you post some photos of the tops of the cutters.
Chainb.jpg
Your top plate cutting angles look OK but for your saw in the size of wood you are cutting you can probably reduce that angle a bit and it should help the saw self feed.

There is some degree of trade off between top players
- top plate cutting angle
- raker angle
- raker top shape
However, if the raker has any sort of a flat top - even if the raker top is sloped - it will penetrate less into the wood which in turn will not allow the cutter to grab as much wood as it could.

Below are two cutters, the top one is Will Malloff's - note the small/narrow size of the raker and how well rounded it is - he is of course using an 090
The other one is mine - my chain has a wider raker but I compensate for this by, as you say, "shark finning" it
Also note my lower raker angle but I'm cutting wider hard wood and even the 880 will not tolerate too high a raker angle
MalloffBobLchain.jpg
Assuming the cutters are OK one way to determine what raker angles suit your wood/saw/cut width is to systemically increase the raker angle by taking a couple of swipes off the rakers and try milling. Repeat this until the chain starts to grab and bog the saw down and at that point you will have gone too far. Now reduce the raker angle by taking some swipes off the cutters. Then measure the raker angle and that's it. Expect a lot of vibe and more chain wear and tear so you will need to make sure you keep the oil up to the chain - under these conditions I'd use an Aux oiler even in narrow cuts.

You need to be aware that if you move to wider cuts then the chain may start to grab again.
 
Just in case newbies are reading this, the "Raker angle" I'm referring to in this post is not the angle on the top of the raker. It's the angle between the cutter tip and the first point of contact the raker is likely to make with the wood relative to the top of the bar. Its the angle in red in the second photo.

It looks like you have plenty of raker angle.

This one has a raker angle of 8.1º (angle of red line to the bar top) but raker has a flat top so raker and cutter won't penetrate as far as the angle would suggest.
View attachment 733263
This one has a raker angle of 8.6º and looks like it has a little bit of rounding on the top of the raker ,so based on both the angle and rounding it should penetrate further.
What concerns me a little is the tips/edges of some of the cutters look slight rounded - see red arrow. It could be just the angle of the photo or the presence of a bit of dirt but these must be have no rounding.
Can you post some photos of the tops of the cutters.
View attachment 733264
Your top plate cutting angles look OK but for your saw in the size of wood you are cutting you can probably reduce that angle a bit and it should help the saw self feed.

There is some degree of trade off between top players
- top plate cutting angle
- raker angle
- raker top shape
However, if the raker has any sort of a flat top - even if the raker top is sloped - it will penetrate less into the wood which in turn will not allow the cutter to grab as much wood as it could.

Below are two cutters, the top one is Will Malloff's - note the small/narrow size of the raker and how well rounded it is - he is of course using an 090
The other one is mine - my chain has a wider raker but I compensate for this by, as you say, "shark finning" it
Also note my lower raker angle but I'm cutting wider hard wood and even the 880 will not tolerate too high a raker angle
View attachment 733265
Assuming the cutters are OK one way to determine what raker angles suit your wood/saw/cut width is to systemically increase the raker angle by taking a couple of swipes off the rakers and try milling. Repeat this until the chain starts to grab and bog the saw down and at that point you will have gone too far. Now reduce the raker angle by taking some swipes off the cutters. Then measure the raker angle and that's it. Expect a lot of vibe and more chain wear and tear so you will need to make sure you keep the oil up to the chain - under these conditions I'd use an Aux oiler even in narrow cuts.

You need to be aware that if you move to wider cuts then the chain may start to grab again.

Thank you, I’m going to take a minute to digest all this info, in the mean time, I cleaned up my chain a little and attached more pictures. I definitely hit a few nails with this chain (it was brand new about 10 slabs ago) which messed up some of the cutters.
87876F74-C51A-48A1-BC01-055681FD0984.jpeg 919CED45-B244-4C70-93FB-2AAA6E34FB21.jpeg61E15640-048A-415E-A528-47872EF898CB.jpegBDD856AC-B7BD-4388-A117-AA6977694E09.jpeg602FF9E9-4660-4F8F-A61E-FBF9D4E13134.jpeg
 
I can see a lot of problems with your cutter tips and I would never let them get this bad.
How often do you touch up?

To fix them they need to be filed to the point where there are no chips. rounded corners or glinting/shadow edges.
The chisel tips on all three of these cutters are either broken off as in B, or rounded as in A and C
These tips should be needle sharp or at least not visibly missing or rounded.
Chainc.jpg

The main cutting edge of the cutters are too ragged or completely worn away, A is bad, B is marginal, but C is terrible.
C looks like it has been left unsharpened far too long and needs a lot of cutter removed to get back the 10º angle and back to a sharp edge.
The edge should be dead straight and there should be minimal "shadow/glint" showing on the edge.
Most of the cutting is done by the hardened chromed plate part of the top plate - if the wood encounters the softer underlaying steel first the chain will just get blunter and blunter.
Don't rely on feel, sharpen under a bright light or the sun and use your eyes and maybe even a set of head magnifiers to look for cutter edge glint.
I try to file the cutter until I see minimal or no glint.

GlintEdge.jpg

Below is semi chisel and its still shows a hint of glint but this will be much better than the edges on your cutters above,

RipOK.jpg

Even brand new chain has some glint on it and can benefit from a touch up.
New.jpg
 
I can see a lot of problems with your cutter tips and I would never let them get this bad.
How often do you touch up?

To fix them they need to be filed to the point where there are no chips. rounded corners or glinting/shadow edges.
The chisel tips on all three of these cutters are either broken off as in B, or rounded as in A and C
These tips should be needle sharp or at least not visibly missing or rounded.
View attachment 733289

The main cutting edge of the cutters are too ragged or completely worn away, A is bad, B is marginal, but C is terrible.
C looks like it has been left unsharpened far too long and needs a lot of cutter removed to get back the 10º angle and back to a sharp edge.
The edge should be dead straight and there should be minimal "shadow/glint" showing on the edge.
Most of the cutting is done by the hardened chromed plate part of the top plate - if the wood encounters the softer underlaying steel first the chain will just get blunter and blunter.
Don't rely on feel, sharpen under a bright light or the sun and use your eyes and maybe even a set of head magnifiers to look for cutter edge glint.
I try to file the cutter until I see minimal or no glint.

View attachment 733290

Below is semi chisel and its still shows a hint of glint but this will be much better than the edges on your cutters above,

View attachment 733291

Even brand new chain has some glint on it and can benefit from a touch up.
View attachment 733292

Thank you again for your time, I think I’m starting to figure this out. I attached a few more pictures after sharpening again this morning.

I raised my file guide in the gullet a little more, and took 20 passes off each cutter, then made the rakers a little more shark fin shaped. There are still a few teeth with chips in them from hitting nails, but I think it’s much better.

It’s pouring rain today, so I can’t work on my big oak, but I have a few 18” wide maple logs in the garage I can test it out on0DD58252-C732-4418-9210-B87F7D70CA97.jpeg8B9DB3D7-4F15-41D5-B1EC-B6D86259D694.jpeg
 
After spending most the day milling and sharpening I’m finally getting close! My Raker angle is still probably a little steep, going through wider logs it’s a little bit ‘grabby’ (and chatters a bit) if the chainspeed falls to far. But on the narrower logs it was screaming through them. Finally getting some nice chips too! Thanks Again BobL, at least I’m on the right track now. Still got a little work to do, but it’s much better than it was before.A4AA55C0-50AD-437A-A525-A457DDA7D80C.jpegDEC4B495-639C-40C6-A96D-EF8CFD64CE05.jpegEB986CB6-2D0B-401B-B39C-90E215765A54.jpeg
 
OK cutters and raker look much better all round. Nice chips too!
I warned you there would be more vibe and chatter and expect more B&C wear and tear.
Are you using an Aux Oiler - if not I would use one and make sure you use plenty of oil.

As for the finish, optimising for cutting speed will invariably compromise the finish especially in narrow width cuts.
Finish also depends on mill rigidity and operator control - mills that bolt to the saws bar bolts, have more than two uprights and wider spaced apart mill rails will generally flex less so generate a better finish than standard Alasakan mills
Operator wise, use a velvet glove approach and try not pushing so hard, the two minutes you save in milling the lab will probably take a lot longer to clean up later on a planer/thicknesser.
Are you using log rails on every cut - if you don't do this then any surface defect from the surface your mill is riding on will be magnified on the following cut.
Are you milling on a slope?
What sort of mill have you go?
 
I havent rigged up an aux oiler yet, been on my list of things to do, maybe I'll rummage around in the basement and see if I can rig something up with some leftover PVC and some random fuel lines I have in the garage.

I am using log rails on every cut, I like having the extra overhang at the beginning and end. Right now its just a frame made of 2x4's that I ran through my planer to get square, I want to pick up some unistrut or something similar, I've already noticed the 2x4 frame warping a tiny bit.

I am milling downhill, I rigged up a setup for lifting logs on and off my trailer which I can also use to set logs on top of other logs to make a nice slope.

I am using the Granberg 778 mill (36" rails), I have a winch on it, but didnt need to use it today.

IMG_0972.jpeg IMG_1135.jpeg
 
Just a comment about winches.
In your setup the tendency is for the winch tension to want to tilt the mill forward.
The rationale that this is OK is that's also the direction/point at which any push on the mill is applied.
I contend that there should be minimal pushing on the mill and instead I apply forward pressure on the saws wrap handle with my knee/thigh/hip which translates to more direct pressure on the bar.
The mill itself is just guided by a hand.

A better arrangement for a winch is as per Will Mallofs setup shown below.
The "pull" direction is direct on the bar and parallel to the cut which will improve the finish
MalloffWinch.jpg
 
I've gotten lazy about my aux oiler. I keep a quart bottle between my rails and every now and then slop some on the tip and return side of the bar. Meanwhile my 660 is set wide open.
 
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