Bar attachment - will this work

[Bongodrummer]

Hi Guys,
First post, so let me start with a big thank you :msp_biggrin: for all the great info on here.
I am building a CS mill, and have a question about how the nose attaches. I was planning to have a bolt through the middle of the roller nose (Stihl Rollomatic ES 30"). So from what I can gather, I want to drill in the middle of the rivets at the nose, like so.

View attachment 275135

Anyway, the question is can I stick a bolt through that hole and into this...

View attachment 275134

without pinching the sprocket?

It is just a pipe with a lump on the end that I have faced square and tapped to accept an M8 tread. My thinking is it would stabilise the bar (side to side)? ...

I have consulted this diagrams and info here http://www.arboristsite.com/milling-saw-mills/93458-2.htm , but am still not 100% sure. If I put pressure on the rivets, even if I only have a small bolt on the bottom side, will the sprocket seize up?

 

[mtngun]

Anyway, the question is can I stick a bolt through that hole and into this
without pinching the sprocket? If I put pressure on the rivets, even if I only have a small bolt on the bottom side, will the sprocket seize up?

The static part of the sprocket bearing is 1" diameter. As long as you stay inside that 1" circle, you won't be pinching anything that moves.

To be sure, try spinning the sprocket with your fingers after bolting the bar to your mill.

 

[Bongodrummer]

The static part of the sprocket bearing is 1" diameter.

Thanks! just the kind of info I was looking for, and without disecting anything :msp_wink:

Ill let you know how it goes...

 

[WidowMaker1]

when drilling threw the Bar, best to drill threw into another Bar or some steel rather than drill threw into wood. I just put a old bar under the bar im drilling and press them down tight together. keeps the metal of the bar your drilling from hardening from the air on the underside when punching threw.

actually when drilling threw the sprocket I use a small round shaped piece of steel, under the Bar... which fits within the inside of the rivits fitting up to the bar tightly so there's no air gap between the bar and steel i'm drilling threw into

 

[Bongodrummer]

actually when drilling threw the sprocket I use a small round shaped piece of steel, under the Bar... which fits within the inside of the rivits fitting up to the bar tightly so there's no air gap between the bar and steel i'm drilling threw into

Sounds like a good plan, thanks :msp_thumbup: Will continue work on it on Monday...

 

[Bongodrummer]

Ok so that weekend stretched to a couple of months as other stuff came up

Anyway the story so far... I wasn't getting through that guide bar with a new HSS no matter the slow speed, coolant and steel backing I was using... Got an 8mm carbide bit :msp_w00t: Was actually a bit shocked at how easily it went through - like a sharp HSS through mild steel!

View attachment 291251

So after that I started to weld some scrap metal I found in the street :msp_wink: (stainless as far as I can tell) - looked to be some old shop display stand or something... Anyway

View attachment 291253

I haven't welded much stainless before, and this was my first experiences of thin stainless. Its fair to say it warped a lot :redface:

Still, I carried on, hoping it wouldn't be too crucial... Here's the crude height adjusting clamp.

View attachment 291255

And an old rollerblade wheel...

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No handle yet but very impatient to try it out while it wasn't raining (and just to see if it was going to work in any way shape or form), so outside we go!

 

[Bongodrummer]

Here's the setup, using my dads ladder (he doesn't know I have screwed some 2x4 onto it yet.. could be interesting - if it works and makes boards he wont mind

View attachment 291258

Yep I know, terrible on knees form, but I wanted to see if this was going to work, and didnt have much time...

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And the first cut was fantastic With a new stihl rip chain on a 30" bar, it was pretty much self feeding, and at a reasonable rate through the Ash log... And the finish was much better than expected too :msp_smile:
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Then it was a big fiddle to re-adjust the height.. It took a trip back to the shop to grind a few mm off the U-bolt which was snagging on the saw's powerhead.

And then problems started :bang: Without the ladder and the height re-set it just didn't want to cut all of a sudden. Tryed sharpening it, jigging about - looked and smelt like the chain was overheating... First thought it had stopped getting chain oil, checked that.. Not the problem.
After a good bit of fiddling, plenty of agitated diagnosis, we are fairly sure we have narrowed the problem down to the mill frame. It wasn't accurate enough and was trying to make the chain cut slightly sideways..

So anyway, when it did work I liked what I saw(ed), but I think I may already be on the brink of making a CSM Mk2... At least all the bits on this one were free scraps...

 

[redoakneck]

I had a roller blade wheel on mine and it melted pretty quick from exhaust hitting it. If you are smelling something you might check that plastic wheel. I found a metal pulley and it works like the wheel just fine.

 

[JHctRednek]

I would try a new chain before I blamed the mill frame, it looks pretty good.
I know that my CSM binds up and wont cut for crap when the chain gets dull, try a regular cross cut chain if you dont have another ripping chain just make sure its "out of the box new" kinda sharp.
Also my experience (which is limited compared to others here) if the nose of the bar is throwing saw dust and you have installed wedges then the bar is tweeked in the frame.

Best of luck

 

[BobL]

After a good bit of fiddling, plenty of agitated diagnosis, we are fairly sure we have narrowed the problem down to the mill frame. It wasn't accurate enough and was trying to make the chain cut slightly sideways.

The bar and the mill frame base must be coplanar or the bar will either dive or try to climb up out of the cut. Even if it is slightly out it may cut for a while but it will wear the bar and chain enough so that eventually the chain will start preferentially cutting on one side and jamb the bar. So not only do you have to fix the mill, check the B&C and dress the bar if needed.

I see you are using one U bolt against what looks like a 1" SHS? I doubt it happened in this case but over time the fact that you need to change the bar height the loosening and tightening of these bolts plus saw vibe at those points could wear the contacts enough to cause that problem in the long run. I would suggest welding a 1/4" thick plate at least 2" wide and tall to the mill frame for the pipe upright to be bolted to and ride against.

 

[discounthunter]

nice work. looks good. i dont think that metal is stainless,but just chromed . its also probably thin.its most likely flexing and possibly warping.

but,defineatly i good starting point.and its producing good results.i would go with something beefier,will add some weight ,but that can help sometimes with a good downward cut.


also,not a fan of wheels.tried several types/sizes,stuck with a modified skid plate.

 

[Bongodrummer]

Hi guys thanks for all the responses!

The bar and the mill frame base must be coplanar or the bar will either dive or try to climb up out of the cut...

I see you are using one U bolt against what looks like a 1" SHS? I doubt it happened in this case but over time the fact that you need to change the bar height the loosening and tightening of these bolts plus saw vibe at those points could wear the contacts enough to cause that problem in the long run. I would suggest welding a 1/4" thick plate at least 2" wide and tall to the mill frame for the pipe upright to be bolted to and ride against.

Hay Bob, first let me thank you for all the good info you provide regarding CSMs on here- sooooo useful!
I think that is exactly what is happening - not coplanar bar diving jazz :msp_mad: Further evidence for this was that one side of the wood was blackening up/burn marks on it - as if just being rubbed by the side of the chain, while the other surface was a nice cut...

There are a few ways that I could try and tweak this - like improving the clamp method, especially at the bar nose, where it is just u-bolted straight to the frame.
As it is though the frame is not flat - when I got it back to the shop that evening and put a flat edge to it I can see about 3mm deviation across its width. So I'll put that down to some good old fashion incompetent welding, and abandon it I think...
What's SHS :msp_confused:

@discounthunter: I originally thought it was chromed MS for sure, but after grinding through it, observing the sparks, and leaving bits out in the wet with no rust, I had to reconsider... Seemed to weld ok with stainless wire anyway, minus the warpage that is... Surprisingly there is very little flex in the frame itself, and it is quite a bit heavier than it looks! Its about 1.5 - 2mm thick wall.

@JHctRednek I did think of trying a standard chain, I thought that may have a little more tolerance to the 'diving into the cut' effect... But I din't have one handy, and figured it would be best to address the cause of the problem.

@redoakneck The wheel seems fine thus far, will have to monitor that, thanks for the heads up - it was defiantly burning cooking oil type smell I was getting, from the overheating chain/GB I presume...

 

[BobL]

Hay Bob, first let me thank you for all the good info you provide regarding CSMs on here- sooooo useful!

No worries.

I think that is exactly what is happening - not coplanar bar diving jazz :msp_mad: Further evidence for this was that one side of the wood was blackening up/burn marks on it - as if just being rubbed by the side of the chain, while the other surface was a nice cut... There are a few ways that I could try and tweak this - like improving the clamp method, especially at the bar nose, where it is just u-bolted straight to the frame. As it is though the frame is not flat - when I got it back to the shop that evening and put a flat edge to it I can see about 3mm deviation across its width.

That will do it!

So I'll put that down to some good old fashion incompetent welding, and abandon it I think...
What's SHS :msp_confused:

Square Hollow Steel.