ROller nose

[BobL]

I'm thinking of modding the BIL mill to take a roller nose bar, currently is uses a hard nose. Can anyone tell me of there is enough hard steel in the middle of a GB roller nose to enable a clamp of some sort to grab the bar at that point without jamming the roller? Maybe take a photo of the roller and post it and show me how much space there is. I want to maximize bar cutting length.

Thanks in advance.
Bob

 

[slabmaster]

Bob,I tried what you want to do and it always pinched the rollers.I think if you want the widest board from any given bar,a hard nose is the only way to go.

 

[woodshop]

I too tried every which way I could to attach the end of my mill to get the very last inch of capacity, but every time I got too close to that roller in any direction or distance from the edge, it would bind. My conclusion was that it was a no-go. One of those deals where you just have to play by the rules. In my case if I want the full capacity of my 36 inch Granberg MKII, I'd have to go with a 40 inch bar and have some of it dangerously stick out the end of the mill, or build a longer guard to go around the extra bar sticking out.

 

[BobL]

Thanks guys, What about if the clamp contact point is only 3/8 inch in diameter? Or, would it be possible to drill a 3/8 or even a 1/4 hole though the centre of the roller nose?

 

[guitarborist]

I tried drilling the tip with 3/8 and toasted the roller. 1/4 might work and I have been thinking about going that route myself; however, I would rather let you try first and let us know if it will work befor I destroy another tip.

 

[BobL]

Before I do anything it would be worth knowing the internal construction of a roller nose. Is it a solid disk that rotates inside a circular case or is it an annulus rotating around a fixed circular plate .



If it's a disc I understand I have no chance but if it has a fixed centre then there maybe a chance.

With the BIL mil I don't need to constrain the bar nose in the sideways direction because the mill is fixed to the bar bolts at the inboard end. All the nose clamp does is hold the bar steady in the vertical. I can in theory not even clamp the outboard end and use it like an extended Granberg small long mill but with a longer bar this is not really a good ideafor accurate height adjustment. I could also just leave a tissue paper gap between the bar and nose clamp but that is not a long term solution either because the shake and rattle and wear away the bar and clamp too quickly.

 

[glennschumann]

For what it is worth, I use a 42" roller nose bar on my 36" granberg. I clamp near, but not on the roller area, and the tip comes within an inch of the guard. I do NOT remove the guard, and leave the tip stick out as was suggested... I keep the guard on and let the excess hang out on the power head end. It is only about 2", and given the apparatus and size of the power head, I have little fear about having excess bar length exposed to my body. It also allows the chain brake to work with the mill attached. My thought is to spend the extra $8 on a slightly longer bar if you are buying one, and not worry about the hours of labor to get an extra cm or two out of a shorter roller nose bar. Of course, milling is all about labor, power tools and accomplishment and that is what makes it a hobby. If machining is a hobby of yours, enjoy away!

Roller noses may be constructed differently. If you can get your hands on a busted one to dissect, that would be your best answer. The Oregon ones I have look like the roller is supported on very short needle bearings around an axle. Like your second image, but with roller bearings in the gap. I have rivets holding the sides together, and if you could weld / braze to that area, you may have a chance of connecting directly to the middle of the roller area. Just a thought... dissecting one before you try may be the best education.

 

[DRB]

Thanks guys, What about if the clamp contact point is only 3/8 inch in diameter? Or, would it be possible to drill a 3/8 or even a 1/4 hole though the centre of the roller nose?

I have a 3/8 bolt through the center of the roller tip on my mill. I just drilled through the center of the roller tip. I have an Oregon bar & roller tip. This has worked fine for me.

As far as the construction of the roller tip. There are bearings in there that ride on a solid center. If I remember correctly. I had one split in half once.

Hope this helps

I was going to take some pics but the batteries are dead. Maybe tomorrow.

 

[BobL]

Thanks Glen and DRB, very helpful!

DRB any pics you can post would be useful.

Cheers

 

[DRB]

Finally got pics

BobL

First pic. is of a bar tip I tried to drill with my way to fast drill press. I was unable to drill all the way through because the metal hardened when it got to hot. I can usually drill through if I keep it cool with lots of oil.

Next pics are of how I have mounted it.

I have had this mill set up this way since I built it a couple of years a ago.

Hope this helps

 

[BobL]

Hope this helps

It sure does, thanks very much.
Two more questions; "What size hole is that, and what brand of bar do you have"?
I have drilled a number of holes successfully in hard nose bars so I know how hard they are and feel confident I can drill another but I just need to know that I can drill one on a roller nose bar. I always start with about a 1/8" drill bit and then go to about 1/4" and then 3/8 which is about the biggest I have drilled in a bar.

I have another problem with my setup in that the mill is firmly attached to the bar bolts on the inboard side of the mill. This means:
- the bar moves out as a I tighten the chain.
- in turn, the outboard clamp does not always clamp in the exact same place on the bar nose.
- adjusting the physical location of the whole outboard clamp every time I tighten the chain would be a PITA.

Nevertheless, If I can drill a hole I have a plan to over come this. Will post once I get the bar, drill the hole and implement the plan.

Thanks to all who have helped.
Cheers

 

[slabmaster]

Bob,Is there some way you can bolt the mill on the bar on the inboard side,that way it won't effect the mounting when the chain is tightened.Mabey drill holes and use spacers if you have to.Sure would be more user friendly that way.

 

[BobL]

Bob,Is there some way you can bolt the mill on the bar on the inboard side,that way it won't effect the mounting when the chain is tightened.Mabey drill holes and use spacers if you have to.Sure would be more user friendly that way.

There are pluses and minuses with the BIL mill design of having the mill mount direct to the bar bolts instead of the bar.

The pluses are
1) Easy to tighten chain as the inboard clamp is not in the way of the adjustment screw.
2) I can swap chains without removing the saw from the mill.
- Loosen 1 bolt on the bar nose clamp.
- Loosen main bar bolts
- Loosen chain adjuster and remove chain
3) The Mill is firmly attached to the power head. This means the bar cannot slip/twist in the mill and contact the bar clamping bolts.
4) And I get 39.5" of cut from a 42" blade.

The minuses are
1) You can't quickly take the saw out of the mill and use it as a straigh CS.
2) I have not yet got it to work with the full extent of a roller or sprocket nose.

But, If I can drill a hole (even a 1/4" hole) in the middle of a roller nose, as per DRB's setup, I should be sweet at least on the roller

 

[DRB]

Bob

I drilled a 3/8" hole and the mill is mounted with a 3/8 bolt. As long as you get the hole centered and it does not start to cut into the rivets that hold the tip together you should be ok.

I have an Oregon bar and tip.

Be sure to post pics of your retrofit.opcorn:

 

[BobL]

Bob Be sure to post pics of your retrofit.opcorn:

Thanks and OK - could be a coupla weeks though till I get my new bars.

 

[BobL]

The new GB 42" sprocket nose and 60" roller nose bars arrived a couple of days ago


and I have been fiddling with BIL mill nose clamp which has up until now been clamping onto a solid nose bar using the all ally clamp. The problem with this clamp is it will just crush a sprocket/roller nose and stop the sprocket/roller from turning.

The old clamp jaw plates are made of 5/16" x 1' x 1" ally plate and welded in place. Step one was to cut through the welds with a Dremel and cutting wheel and remove the old ally jaws.

Next make 2 steel new jaw plates 1" wide by 1.5" long by 1/4" thick

I milled the 1/2" wide slots using my big drill press, a cross slider vice, and carbide cutter.

Driil, tap and screw the steel jaws onto the solid ally bar supports using 3/6" countersunk screws.


The slots in the steel jaw plates are to accommodate the head (in one slot) and nut (in the other slot) of a small (1/4") tensile steel nose bolt that fits in a hole thru the centre of the bar nose. The nose bolt only permits the centre of a roller nose to be gripped by the steel jaw plates attached to the clamp.

Sorry its a bit hard to see the bolt. In this photo I'm practicing on the old hardnose bar.

Her you can see the nose bolt thru the bar nose and how the head sits in the slot.

Why do I need the slot - that's because when I adjust the chain tension the bar needs to be able slide forward because the mill is mounted on the bar bolts (not the bar) at the inboard end.

 

[BobL]

Here you can see the clearance of the bar from the steel jaw plates.
This is still the hardnose bar

The steel jaw plates only grip the central nose bolt which allows the sprocket and roller to only be gripped in the very middle.
The red two ended arrow shows the range of forward and backward movement possible during chain tensioning.
The other big bolt is what pulls the two jaws closed onto the nose bolt

Here is the roller nose bar - plenty of clearance there.

Adjusting the chain involves. Loosening the nose clamp, the bar bolts at the power head, tightening chain and remembering to tight up all the bolts.

Fortunately the GB roller nose came with a hole in the centre of the nose already. I haven't tried the sprocket nose because I have to (VERY CAREFULLY) drill a hole - although the nose is replaceable if it all goes pearshaped.

The Hardnose bar can work with or without a bolt in the middle of the nose. It is actually better not to use the bolt with the hardnose bar because you gain about a 1/2" of cutting length by clamping direct into the bar.

Next I have to modify the aux oiler to suit all the bars.

 

[BobL]

New Aux oiler delivery point for BIL mil

Pics pretty much say it all.

Top view, Brass plate (from and old x-ray machine) attached to the top part of the bar nose clamp.

Other side view. Piece of 3/8" brass ll thread with hole drilled down the middle attached to the brass plate.

You can also see the old thru the bar oiler in this shot.

Tip of delivery line is placed 2 mm from chain.

Adjustment bolt allows oiler to be repositioned by rotation to account for different bar nose location and different radii nose bars so that the delivery point is precisely above the chain/bar line.

Cheers

 

[BobL]

Just want to report I managed to successfully drill 1/4" holes through the centre of two sprocket noses on 24" bars. The bars were well used Stihl bars so it did not matter if they died in the process.

The metal at the centre of the sprocket was somewhat harder than all other holes I have drilled in any Oregon, stihl or GB bar which I have successfully drilled aux oiler holes for in the nose using a new quality HSS drill bit, slow speed and lots of lube.

I used a new sharpened (green wheel) carbide tipped (masonry) bit, 160 rpm, lots of cooling lube press - in a heavy duty drill press, a fair bit of pressure was required. New masonry bits are not very sharp and rely on crushing the masonry so I had to spend some of time grinding off carbide to get an edge and a point.

The hole drilling took some time but it got thru, leaving a big bur on the exit.

Although it looked OK I touched up the carbide bit and on the second bar it got about 1/2 way thru before the carbide tip just crumbled. I think I was probably pushing it too hard. I finished that hole using an old (newly sharpened) masonry bit. This time I paused when the hole just broke thru the bar and turned the bar over to stop the bur forming.

The first bar had a very free (bordering on sloppy) sprocket to begin with and it was equally free after I had drilled the hole, The second one has a smooth but firm sprocket , which was not turning freely after I had finished drilling however after a number of alternate washing with meths and lube it freed up fine. I suspect some of the swarf may have got down into the sprocket.

I now feel confident to drill a hole in my new 42" GB sprocket nose. This nose is replaceable so all is not lost if it jams.

 

[woodshop]

Very interesting Bob... as usual well documented with ample pics so everybody can see what you're talking about. I like how you test the waters on a disposable before tearing into a good bar, smart. You have more patience than I. I also like your newer method of oil delivery. Although I have not had a need for an aux oiler on my csm as my 395XP seems to deliver enough where the chain never really gets dry, if I did add one I'd try and go with your newer method if I could rig up a way to mount it on my Granberg MK III similar to the way you did. I'm sure I could with a little finagling and making a mount for it that could be adjustable as yours is so I could fine tune the delivery point. Great idea. You're fine tuning that thing into a true mechanical work of art.