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Do I need a riving Knife

Started by timbatrader, November 16, 2010, 11:09:34 PM

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timbatrader

Hi all I am new to portable milling Have just bought a second hand Peterson Skillmill Their baby swingsaw mill The guy I bought it off had never used it he traded it for his boat then sold it for cash. When I put it together lots of bolts etc missing most sorted but it still has the riving knife missing . the mill works fine without it I am wondering do I need to order a new one ? Did the first owner remove it for a reason ? I reckon If I ask Peterson they will be obliged to say it is needed for safety But I would like to here from other swingsaw users specialy Skillmill use's if they still have riving knifes on there saws

ErikC

 It will work without the knife, but not as well. The cut will be slower, and the blade may overheat from the extra friction. It's pretty simple to mount, so figuring it out should be easy, I would get it on there if I was you.
Peterson 8" with 33' tracks, JCB 1550 4x4 loader backhoe, several stihl chainsaws

weisyboy

it will cut without it, but not well and not safely.

the blade will heat and jam, and leave marks in your timber. grab and throw saw back or stall motor.
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r.man

For those of us who don't know swingsaws what is a riving knife and what does it do? Always good to learn something new.
Life is too short or my list is too long, not sure which. Dec 2014

okie

Quote from: r.man on November 17, 2010, 09:52:04 AM
For those of us who don't know swingsaws what is a riving knife and what does it do? Always good to learn something new.
It is a curved piece of metal slightly thicker than the blade that trails behind the blade closely in the cut, it keeps pressure off the blade.
Striving to create a self sustaining homestead and lifestyle for my family and myself.

beenthere

But thinner than the kerf?   ..or not?
south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

ErikC


On my saw it is thinner than the blade, just about 1/8" I think. It is sickle shaped, and mounts behind the blade a couple of inches. Someone may have a photo, I don't in my gallery. If you need it for the project I will put a couple up for you.
Peterson 8" with 33' tracks, JCB 1550 4x4 loader backhoe, several stihl chainsaws

Burlkraft

https://forestryforum.com/media/sharpening_peterson_redwood.wmv

Here's a link to a video shot at the redwood saw we had and there is a shot of Chris sharpening my blade

You can see the knife there

   
   And here is a pretty good picture  ;D
      
   https://forestryforum.com/redwood2/images/DSC04070.jpg
Why not just 1 pain free day?

Nate Surveyor

(assuming that you now have a riving knife)
I don't know if this is very important on the little skilmill, but it does affect the amount of pressure needed to push the mill through the log.
IF you hit a wad of sap,  (Southern Yellow Pine sap) the riving knife will not slide easy. Clean and spray it with silicone spray.

Just a bit easier to use now!

N
I know less than I used to.

Captain

I'm going to differ in opinion than most of the previous posts....

The riving knife is there to make sure the just cut piece does not pinch the blade when exiting the cut.  For that reason alone I would put one on.  It also helps keep the blade from being pinched when a tensioned piece of wood is being cut.

It will cut fine without it in "normal" cutting, especially on the skillmill where your peices will be smaller and not tend to pinch the blade as much.

Captain

terrifictimbersllc

This is also called a splitter on a table saw, where it keeps the work from pinching the back of the blade and being thrown forward.  Am guessing on a swing mill it could be the saw that is thrown if the blade is pinched.
DJ Hoover, Terrific Timbers LLC,  Mystic CT Woodmizer Million Board Foot Club member. 2019 LT70 Super Wide 55 Yanmar,  LogRite fetching arch, WM BMS250 sharpener/BMT250 setter.  2001 F350 7.3L PSD 6 spd manual ZF 4x4 Crew Cab Long Bed

ErikC

 The saw head won't get thrown around if it binds. That is the main reason why the directions are specific that moving the carriage forward MUST be a horizontal cut, if cutting contrary to the design then the blade can pull the saw away. If my saw binds severely the belts just slip, or the engine may stall if you have a lighter hp motor.
Peterson 8" with 33' tracks, JCB 1550 4x4 loader backhoe, several stihl chainsaws

captain_crunch

Don't know Squat about a band mill but a circle saw without a (sail) or splitter is suside if there is any bind in log. Mine is only 6 in beond blade and have seen times when I had to grab falling wedge to hold cut open to get it to splitter :o :o
M-14 Belsaw circle mill,HD-11 Log Loader,TD-14 Crawler,TD-9 Crawler and Ford 2910 Loader Tractor

weisyboy

Quote from: ErikC on November 17, 2010, 11:26:35 PM
The saw head won't get thrown around if it binds. That is the main reason why the directions are specific that moving the carriage forward MUST be a horizontal cut, if cutting contrary to the design then the blade can pull the saw away. If my saw binds severely the belts just slip, or the engine may stall if you have a lighter hp motor.

i disagree, i have had the mil throw back towards me and almost knock me over, i have had small logs get thrown out the front of the mill also, this was even with the knife on, caused by them pinching on the saw.

if you splip your belts your not gettin the full potetial outa your motor.

the riving knife should be slightly smaller than your saw kerf, only be a fly [I have typed a profane word that is automatically changed by the forum censored words program I should know better] thow.
god bless america god save the queen god defend new zealand and thank christ for Australia
www.weisssawmilling.com.au
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weisyboy

god bless america god save the queen god defend new zealand and thank christ for Australia
www.weisssawmilling.com.au
http://www.youtube.com/user/weisyboy?feature=mhee
http://www.facebook.com/profile.php?id=100000696669814&sk=photos

terrifictimbersllc

DJ Hoover, Terrific Timbers LLC,  Mystic CT Woodmizer Million Board Foot Club member. 2019 LT70 Super Wide 55 Yanmar,  LogRite fetching arch, WM BMS250 sharpener/BMT250 setter.  2001 F350 7.3L PSD 6 spd manual ZF 4x4 Crew Cab Long Bed

ErikC

Quote from: weisyboy on November 18, 2010, 02:48:05 AM
Quote from: ErikC on November 17, 2010, 11:26:35 PM
The saw head won't get thrown around if it binds. That is the main reason why the directions are specific that moving the carriage forward MUST be a horizontal cut, if cutting contrary to the design then the blade can pull the saw away. If my saw binds severely the belts just slip, or the engine may stall if you have a lighter hp motor.

i disagree, i have had the mil throw back towards me and almost knock me over, i have had small logs get thrown out the front of the mill also, this was even with the knife on, caused by them pinching on the saw.

if you splip your belts your not gettin the full potetial outa your motor.


the riving knife should be slightly smaller than your saw kerf, only be a fly [I have typed a profane word that is automatically changed by the forum censored words program I should know better] thow.

The difference may be I have a peterson wpf, and the carriage is heavier than the Lucas. Sometimes it grabs and jerks a couple inches, but that's all.As far as the belt slipping, if they aren't slipping during normal work, but will if the saw binds, something has to give and that's a good place as far as I am concerned.
Peterson 8" with 33' tracks, JCB 1550 4x4 loader backhoe, several stihl chainsaws

woodsteach

My Brand X swing mill does not have one.  Makes double cutting real easy.  ;D

Carry a plastic splitting wedge with you to keep the blade from getting pinched. 

When cutting say 2 x6's have the 6" be the vertical cut and you'll probably never have the blade get pinched.

I second what ErikC said about the belt slipping IF the blade gets pinched.  I'd rather have that happen than WB's saying he's shot out logs and almost been knocked over by his mill!  :o :o   Yep slip the belts and keep extras on hand!  In 6 years of milling I think I've gone through maybe 4 sets of belts at $20.00 per set.

woodsteach
Brand X Swing Mill, JD 317 Skidloader, MS460 & 290, the best family a guy could ever dream of...all provided by God up above.  (with help from our banker ; ) )

ErikC

  Putting a little thought into what Captain and Woodsteach said about it not being that important---- The blade is making a horizontal cut first most of the time, that leaves the entire uncut edge as support. So unless there is enough tension to overcome that, I guess it's not likely to bind, and the knife isn't part of the vertical cutting process anyway. Maybe if a person cuts the horizontal cut last, as some do when working alone, or cuts a lot of really bound up timber, it would be a bigger concern than for others.
Peterson 8" with 33' tracks, JCB 1550 4x4 loader backhoe, several stihl chainsaws

weisyboy

when doing the deep verticle cuts the knife isnt as important especial if you do the Horasontal first, the riving knife dosent get in the way of doubled cutting, i have moded my mill to double cut, and the riving knife stays on.
god bless america god save the queen god defend new zealand and thank christ for Australia
www.weisssawmilling.com.au
http://www.youtube.com/user/weisyboy?feature=mhee
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ErikC

 Right, on the Peterson it never gets in the way of double cuts either.
Peterson 8" with 33' tracks, JCB 1550 4x4 loader backhoe, several stihl chainsaws

timbatrader

Thanks guys for all the advice. I cut a log with a bit of tension in it today. I have worked out I don't need a riving knife I need two. With a skillmill flipsaw when you put the saw vertical or cut on the other side of the log to get a double width board you use the backside of the blade ie other side of the shaft Both sides need a riving knife. The blade was loading up in the cut I slowed the feed then stopped still no revs so reversed but blade still pinched and popped the overload. I got through it latter on by taking very small cuts and pouring on heaps of water ie having the garden hose running on the saw

weisyboy

yep, its got me beat why they never put double rivin knives on the swing mills, it wouldnt be hard and would be much better.

the only one that has is the one known as eco saw or death on rails as i call it.
god bless america god save the queen god defend new zealand and thank christ for Australia
www.weisssawmilling.com.au
http://www.youtube.com/user/weisyboy?feature=mhee
http://www.facebook.com/profile.php?id=100000696669814&sk=photos

Meadows Miller

Gday

I didn't think the skill mill had one did they  ??? Im with Capitan he's spot on with his take on things  ;)  ;D My thought's exactly on the  the Lewi/ecosaws Carl  ;) :D ;D they did do what they where originally intended for but they never  refined the mill any further  ;)

Edit the Lewisaws are also a pita of a mill to operate as you have to either take your timber out from either over or under the rails  :) :) :) ??? ::)

Regards Chris
4TH Generation Timbergetter

weisyboy

lewis saws were good, eco saws where crap. thts why tehy are no longer made or sold in australia.

i know the bloke who ownes the company hes a great bloke, and all that but clueless about sawmilling and maufacturing.

iv never had the pleasure of using the skill mill, one of the few mills around i havent used, that and one of those horizontal bandsaws like the woodmizer. i wouldnt think tehy woudl be alowed to be sold without riving knives, but then none of the mobile saws meet OHS specs in aus, they state that 100% of the blade not in the cut must be covered, that is just not possible on a swing mill or twin blade mill.
god bless america god save the queen god defend new zealand and thank christ for Australia
www.weisssawmilling.com.au
http://www.youtube.com/user/weisyboy?feature=mhee
http://www.facebook.com/profile.php?id=100000696669814&sk=photos

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