Roller or sprocket nose Distance

[BobL]

I'm modifying my small alaskan mill to handle a sprocket or roller nose bar (currently I use a hardnose bar and the mill uses a single sided clamp but this would not work for a sprocket or roller nose bar).

I've made the clamp and now I want to add a nose guard. What I need to know is a typical distance X on the diagram.

My small mill has a spread of between 16 and 24" so my guess is I would need to know "x" for up to about a 28" bar.

Thanks

 

[aquan8tor]

I'd give about 3.5-4" for the sprocket to completely clear the clamping mechanism, otherwise you'll pinch the sprocket, as the bar isn't solid at the nose. I encountered this the other day & snapped my lopro chain AGAIN. I was trying to get the very max out of a 20" bar for a cherry log the neighbor had taken down after it got struck by lightning (sorry no pics-digital camera is broken--can't afford a new one b/c I keep spending money on tools )
Sorry to thread hijack. I'd give 4", knowing you may be able to get by with 3", plus at least 1" for clearance between the chain & the guard-----5" total should get you by.



Nate

 

[BobL]

I'd give about 3.5-4" for the sprocket to completely clear the clamping mechanism, otherwise you'll pinch the sprocket, as the bar isn't solid at the nose. I encountered this the other day & snapped my lopro chain AGAIN. I was trying to get the very max out of a 20" bar for a cherry log the neighbor had taken down after it got struck by lightning (sorry no pics-digital camera is broken--can't afford a new one b/c I keep spending money on tools )
Sorry to thread hijack. I'd give 4", knowing you may be able to get by with 3", plus at least 1" for clearance between the chain & the guard-----5" total should get you by.

Thanks Nate. Of course I could make it ridiculously long but I just want to clear the roller/sprocket. All my bars are solids but I was thinking it would make the little mill more versatile especially as I was thinking of going down south to a mates property this summer and I know all his saws have sprocket noses.

 

[CaseyForrest]

I was always able to clamp a sprocket nose bar right in the center of the sprocket. Using a GB mill the front clamp was just a bolt that pinched the bar. Never had an issue pinching the bearing unless I didnt get it dead center. And after a few times the paint wore off where the bolt needed to be so placement was very easy.

 

[woodshop]

I have mine 1/4 inch from the sprocket circumference. I have tried and it will not pinch the sprocket on my Windsor 36" bar even if the clamp is directly next to the circumference, but I give myself a quarter inch just for peace of mind.

 

[aquan8tor]

I think mine was about 1/4" the other way---on top of the sprocket, on a tsumura carlton bar. I didn't realize it was pinching it, and the extra friction heat was too much for that little chain. I haven't used any but the windsor hard tips before, but my next bar will be one of their speed tips.

 

[BobL]

I have mine 1/4 inch from the sprocket circumference. I have tried and it will not pinch the sprocket on my Windsor 36" bar even if the clamp is directly next to the circumference, but I give myself a quarter inch just for peace of mind.

So what's "X" on your setup?
Thanks

 

[woodshop]

So what's "X" on your setup?
Thanks

I just measured it, and I get exactly 2 1/2 inches (62 mm) from the outer end of the csm clamp where it clamps, to the end of the 36 inch Windsor speed tip, not including the sprocket teeth that stick out a little past the end, nor am I including the chain. To get X in your diagram, I guess you would have to add however much the height of the chain is, about 1/4 inch, but that would vary with the kind of chain. I have 3/8 (.375) round ground chisel skip on there now.

The very first time I clamped my bar in my Granberg and tightened it down, the chain would not even budge because the clamp was pinching that sprocket so tight. Rookie blunder... took me a few minutes to even figure out what was happening.

 

[BobL]

I just measured it, and I get exactly 2 1/2 inches (62 mm) from the outer end of the csm clamp where it clamps, to the end of the 36 inch Windsor speed tip, not including the sprocket teeth that stick out a little past the end, nor am I including the chain. To get X in your diagram, I guess you would have to add however much the height of the chain is, about 1/4 inch, but that would vary with the kind of chain. I have 3/8 (.375) round ground chisel skip on there now.

The very first time I clamped my bar in my Granberg and tightened it down, the chain would not even budge because the clamp was pinching that sprocket so tight. Rookie blunder... took me a few minutes to even figure out what was happening.

Thanks Woodshop for the prompt reply. I will make the guard 4" from the clamp. I've also worked out a way not to weld the guard onto the clamp so I can make a bigger or smaller guard for a specific bar if required.

 

[Railomatic]

Did you know that you can drill the centre of a roller nose sprocket, we do this on all our bars, there is sufficient centre thickness on most bars to do this, without any ill effects to the bearing, this give you another three inches of cutting width.

Davy.

 

[MikeInParadise]

On my Alaskan mill that distance is 4 5/8".

Excuse the blurry pic but the mill is up on a shelf and I just pointed the camera and clicked without being able to see...

 

[BobL]

On my Alaskan mill that distance is 4 5/8".

Excuse the blurry pic but the mill is up on a shelf and I just pointed the camera and clicked without being able to see...

Thanks Mike. No worries about the blurry pic. I've allowed 4" and that looks fine.

Thanks Railo, I know about the drilling but reason I'm not is because some saws I may use in this small mill do not belong to me.

 

[BobL]

OK - here is the full story from the begining.

On this small (16 - 24") CS mill.

The outboard or nose clamp looks like this.

It works very well, its quite a bit safer than a conventional outboard bar clamp, but is not suitable for roller or sprocket noses.

I'm keeping the current vertical and clamp but I've made it interchangeable with this vertical and clamp. I don't have any sprocket or roller nose bars so I'm showing it here with a 20" hardnose.

The transparent cover is 1mm thick polycarbonate.

Underneath it looks like this.

I've kept the underneath clear so I can add an aux oiler an d maybe water cooling.

The extra bar on the end is a handle.

The clamp is made from 0.062" thick 3/4" SHS.
The nose guard is made from 0.047" thick 3/4" SHS - twas a PITA to weld with a stick welder. The Nose guard can be removed for whatever reason.

BTW (for woodshops benefit) today I also
- put up the shade sails (annual chore before summer sets in)
- fixed a porch light
- swept up the back yard brick paving
- pruned/slashed a vine taking over the japanese bamboo
- did the washing
- and had a nap.

Cheers

 

[woodshop]

Nice... I like the plastic over the business end of the bar in front of the hand hold. I could see somebody grabbing the handle and reaching a bit too far and before they know it their fingers are hamburger.
Bob you should go into business as an engineering consultant... um, maybe you are now.

 

[BobL]

Nice... I like the plastic over the business end of the bar in front of the hand hold. I could see somebody grabbing the handle and reaching a bit too far and before they know it their fingers are hamburger.
Bob you should go into business as an engineering consultant... um, maybe you are now.

Thanks WS.

RE:I could see somebody grabbing the handle and reaching a bit too far and before they know it their fingers are hamburger.

I also feared might be the case but the polyc comes down in front of the handle by some 2" and you'd had to have hands like king kong's to reach that far. Might just put a shortreturn on the polyc to rule out a king kong event.

RE: engineering consultant
No thanks - with my luck i'd be consulting on a leaking toilet!

 

[woodshop]

Thanks WS.

RE:I could see somebody grabbing the handle and reaching a bit too far and before they know it their fingers are hamburger.

I also feared might be the case but the polyc comes down in front of the handle by some 2" and you'd had to have hands like king kong's to reach that far. Might just put a shortreturn on the polyc to rule out a king kong event.

RE: engineering consultant
No thanks - with my luck i'd be consulting on a leaking toilet!

Problem I could see enclosing that end any more though would be having to clean it out. I think it would load up pretty thick in that case. On my csm the area at the end of that nose gets full of oily sawdust "cake" to the point where I have to scrape it out every once in a while. Of course I have my oiler cranked up full on the saw all the time when milling. On my Husky 395 it not only seems to keep the 36" bar oiled, but often I can see excess oil being spit out the end. Thus the accumulation. Maybe you for whatever reason don't have that much of a problem there.

 

[BobL]

Problem I could see enclosing that end any more though would be having to clean it out. I think it would load up pretty thick in that case. On my csm the area at the end of that nose gets full of oily sawdust "cake" to the point where I have to scrape it out every once in a while. Of course I have my oiler cranked up full on the saw all the time when milling. On my Husky 395 it not only seems to keep the 36" bar oiled, but often I can see excess oil being spit out the end. Thus the accumulation. Maybe you for whatever reason don't have that much of a problem there.

Yes I could see that as a problem but a compressor can easily blow it out at the end of a milling day. Of course you need access to a compressir but the yard where I mill has a big compressor and I also have one in my shed. Using the water chain cleaning idea also helps. Although it sprays wet/damp sawdust around, accumulation in one spot is a bit less that that from oily sawdust.