Thread: Chainsawmill running really hot :-(

well done on your risk assessment

I think a lot of us should look at that before and after we use our mills and chainsaws

it has been a while since I heard a lot of those facts

especially sun stroke to often we don't think about that

and always remember your back

p.s. we do the same thing so often we should do something different every now and then.
ie. move different parts of our body's, don't fall victim to the old loggers syndrome

thanks for the wisdom MR BobL

CHEERS Rob

Finally I've got the pics of the mods I made last week to my mill. They may not seem like much but there was a lot of, put the saw on the mill, take the saw off the mill, file that, adjust this and repeat, repeat, repeat.

I put on of the dog spikes back on to the saw body and modified so that I can use it to stabilise the power head. This removes all the lateral movement that comes from the interaction between the saw mount and the saw.

Attachment 124084
Attachment 124087

Also modified the saw mounting points into key hole shapes so that I can slip the saw on and off. I'm not happy with this becuse the nuts still get caught on the saw mount when I'm trying to take it off. I think that I will have to add a piece of wood that goes inside the saw mount to stop the head of the bolts catching on the edge of the keyhole shaped hole when I want to remove the saw.

Attachment 124085

Also note the bolt head on top of the saw mount. This is a setscrew that has a nut behind the bolt head to secure it to the top of the saw mount and then two nuts either side of the bottom of the saw mount. This acts as a pillar within the saw mount further stabilising the saw mount. If I could weld a better solution would probably be two pieces of 50mm RHS welded together side by side. Since I havn't learnt any welding skills yet this will do.

To stop the threaded rod on the power head side from flexing towards the log when cutting I added another strut to the carriage.

Attachment 124083

What was happening was that the saw would pull itself towards the log and then the elasticty of the rod would pull the saw back, then the saw would pull itself towards the log.... you get the idea. I had been stopping this by holding the saw more securely but this is better. I'm pretty confident that this mod will work since I clamped a piece of wood in place last time I was milling to test it.

Finally I modified the tip mount so that I can just slip the tip into the mount and then tighten it up.Attachment 124086

I've also got rid of the metal washers and replaced them with a single wooden washer to give more lateral stability to the tip.

Hope that is all as clear as mud.

Still to do:

Improve winch;
Remote throttle;
Add measuring guague of some sort.;
Make saw slip off saw mount more easily; and
Find more things to fix.

Some good mods there weaver

I assume you want to be able to easily remove your saw from the mill to use it for regular cutting? I was in the same position for a while and it drove me nuts. It sounds like a lot of your problems could be eased by dedicating the 075 to the mill and saving pennies to get another saw?

Originally Posted by weaver

.
.
What was happening was that the saw would pull itself towards the log and then the elasticty of the rod would pull the saw back, then the saw would pull itself towards the log.... you get the idea. I had been stopping this by holding the saw more securely but this is better. I'm pretty confident that this mod will work since I clamped a piece of wood in place last time I was milling to test it.

This is a perennial problem with carriage and alaskan mills especially those low mass or with flexible structures. On an alaskan, wheels effectively remove this problem but it's more difficult to do this on a carriage. One way might be to just add heavy weights to the carriage. One guy I know added a big cookie to the top of the carriage but I note you have your adjuster chain on the top of your carriage. Some suitably applied chunky occy straps might help dampen things down as well. On my mill I have an occy strap between the uprights and it stops the inboard one from smacking me in the teeth

Originally Posted by BobL

Some good mods there weaver

I assume you want to be able to easily remove your saw from the mill to use it for regular cutting? I was in the same position for a while and it drove me nuts. It sounds like a lot of your problems could be eased by dedicating the 075 to the mill and saving pennies to get another saw?

Thanks. No it is more so that I can change chains easily. On pine it is not a problem but I've got logs of wattle, blackwood, messmate and box lined up.

Originally Posted by BobL

This is a perennial problem with carriage and alaskan mills especially those low mass or with flexible structures. On an alaskan, wheels effectively remove this problem but it's more difficult to do this on a carriage. One way might be to just add heavy weights to the carriage. One guy I know added a big cookie to the top of the carriage but I note you have your adjuster chain on the top of your carriage.

Not sure I understand what you mean by the cookie but I'm pretty sure that piece of wood that I have added has fixed that problem. The flex was in the threaded rod not the carriage it self and with the new strut on the carriage the upright of the saw mount prevents the saw from moving towards the log. Since the rod cant flex very much (only 1-2mm) it dosn't get enough elastic strength to bring the saw back. At idle there is a gap of 1-2mm between the saw mount and the strut. Under power the saw mount upright rests against the strut. Basically stops the oscillation before it can begin.

Originally Posted by weaver

Thanks. No it is more so that I can change chains easily. On pine it is not a problem but I've got logs of wattle, blackwood, messmate and box lined up.

I see. There are relatively simple designs for carriage CS mills that permit the chain to be swapped without removing the saw from the mill, but unfortunately they do require doing away with your clutch cover and chain brake Even though I touch up chains while it is on the mill, being able to remove the chain while the powerhead and bar are on the mill was a top priority for my mill design and it has been well worth it.

Not sure I understand what you mean by the cookie

It's a stumpy log, wider than it is tall. It just adds weight to the carriage.

I got the mill going this morning and cut six slabs about 400-450mm here are the results, well the consequences anyway.

Chain from both sides:
Attachment 124201
Attachment 124202

Collection of sawdust on nose of the bar:

Attachment 124203

Collection of sawdust near powerhead

Attachment 124204

Wear on bar from power head end to nose.

Attachment 124197
Attachment 124198
Attachment 124199
Attachment 124200

Bear in mind that I had just redressed the bar before doing any cutting this morning.

I am surprised that the paint on the bar hasn't smoked itself off if you are getting wear that bad. When you dressed the bar did you run the edge of a square edge file at 45 degrees down the grove to remove any burrs possibly left in the groove? to me if the first pic of the bar wear is the top the way it has worn looks to me that the bar groove is slimmer than the thickness of the drive tangs or there is burring on the edge of the groove which is causing the chain to bite in. Either that or tension is just way too tight. it is a bit hard to see but in the pic showing the build up of sawdust is it the auxilliary oiler running to the bar at the powerhead about 4 inches up the bar? normally that would be at the tip end so that you are oiling the return side of the bar.

Just out of interest what oil are you running?

not running 58 thou chain on a 63 though bar?
This is the wear I have after 4 tanks of fuel on a 20 inch bar which should wear quicker than a bigger bar
https://www.woodworkforums.com/member...bums/bar-wear/

As you can see I haven't even rubbed the machine marks out from new and haven't even taken the paint off the shoulders. There is a little wear on the tip and on the return end of the bar nearest the sprocket.where it goes around the bit of a shoulder but no where near the amount you are showing. And I noticed that this bar has a bit of a bow in it when I took these pics, not something you would expect from a new bar.

Originally Posted by Travis Edwards

I am surprised that the paint on the bar hasn't smoked itself off if you are getting wear that bad. When you dressed the bar did you run the edge of a square edge file at 45 degrees down the grove to remove any burrs possibly left in the groove? to me if the first pic of the bar wear is the top the way it has worn looks to me that the bar groove is slimmer than the thickness of the drive tangs or there is burring on the edge of the groove which is causing the chain to bite in. Either that or tension is just way too tight.

Yep it looks too tight to me.

Just out of interest what oil are you running?

Good Question.
Also is your powerhead oiler turned up to max?

not running 58 thou chain on a 63 though bar?

The CS will cut in a curve until it jams.

Is that a hard nose bar your running? if it is I would say your chain is too tight & your getting excessive wear on the bar. You really need to run a sprocket nose bar or similar to stop wasting power & adding load to the saw that doesn't have to be there. Hard nose bars should be run with a few mm slack from the chain to the bar ( midpoint )
regards inter

What they said about chain tension, oil type and amount of oil used.

But I'm wondering what brand is the bar? Can't see any branding on it and I'm wondering if it's made from inferior materials???

Originally Posted by weaver

I've just found out that you can't post on old threads

One of the last posts on Bobl's thread about his anti bar sag device had a question about whether titanium bars sag. I was going to add to the thread that they do since mine is and it does (I know that there is a word for sentences like that I wish I could remember what it is).

how can you be doing that kind of damage to a roller nose titanium bar???

Originally Posted by BobL

Yep it looks too tight to me.

Well it seemed a bit loose to me. A couple of times the chain seemed to be almost running clear of the bar on the top side. It may just be that I don't have the experience to judge tension on the extra long bars. If that is the case the Calm will set me straight tomorrow when he visits.

Originally Posted by BobL

Good Question.
Also is your powerhead oiler turned up to max?

Yep, but if you look at the pic of the powerhead end on the bar in situ you can see I'm adding extra oil there as well.

Originally Posted by BobL

The CS will cut in a curve until it jams.

While I'm sure it will turn out that I'm doing something simple wrong it is not using the wrong gauge of chain. The recent pics are of a new chain I made up but it is the same guage as the Chain that Sawchain supplied me with the bar.

Originally Posted by weaver

A couple of times the chain seemed to be almost running clear of the bar on the top side.

While it looks scary that is entirely normal and a newbie operator should resist the temptation to over tighten the chain after seeing the chain do that.

At the beginning of a cut the chain gets hot quickly and so expands quickly, much quicker than the bar. On a long bar it is easy to calculate the extent of expansion and demonstrate that the chain can expand so much it can fall off the bar. This is why it is important to start the cut slowly so the bar then gets a chance to heat up and expand and hold the chain on the bar.

If the chain is retensioned after making a short cut so the chain is hot but the bar is still relatively cool, when the bar finally reaches equilibrium temperature it can expand so much that it will tighten and stretch the chain and produce the sort of bar rail wear you are observing.

Originally Posted by BobL

While it looks scary that is entirely normal and a newbie operator should resist the temptation to over tighten the chain after seeing the chain do that.

At the beginning of a cut the chain gets hot quickly and so expands quickly, much quicker than the bar. On a long bar it is easy to calculate the extent of expansion and demonstrate that the chain can expand so much it can fall off the bar. This is why it is important to start the cut slowly so the bar then gets a chance to heat up and expand and hold the chain on the bar.

If the chain is retensioned after making a short cut so the chain is hot but the bar is still relatively cool, when the bar finally reaches equilibrium temperature it can expand so much that it will tighten and stretch the chain and produce the sort of bar rail wear you are observing.

That is good to know but I did not re-tension the until maybe the 5th slab ie definitely after the fourth but it could have been after the 5th.

That would also mean that any mill design would have to allow for that expansion. YOu wouldn't want to spend a stack of time and money building a rock solid fram only to find that when the bar expands things go a wry. How much expansion are we talking in a titanium bar. It would be measured in mm of expansion/mm length of bar/˚C yes?