So bought a chinese saw (holz g070)

[J D]

Looks like CAD is establishing itself nicely
You can usually drill the bars with a well sharpened bit running slowly in a press... use cutting compound & go slow, if you press on a dull bit the heat will further harden the bar

 

[sliceoflife]

Tried that, but my (brand new) titanium bits weren't doing much of anything even going at a snails pace with loads of cutting oil and I didn't have anything that small in cobalt. Diamonds got through but damn it took its toll on the nickle plating that held them. If I planned on doing it more than once I'd buy the cobalt bits I need, but since it's just the one and I'm a hairs breadth away from through; I just bought another diamond set (they're cheap).

And yeah, I probably should just follow through on what I'm thinking of doing (mod the g070 to a 090) and keep it and the Super XL (for bucking) then I'd be set. Going to take the echo out after work and see how it runs with the modded muffler, and test the 775d to see if it needs anything. But assuming they're both running well; then I just need to finish the bar mod; pick up a chain for the mac bar and get the Super fixed up and I'll be set up for at least a bit.

 

[sliceoflife]

New bits arrived and first bit disintegrated in about 2 minutes of doing very little... but second bit finished the cut beautifully in less than two seconds... so now I just have to make sure I clean all the diamond particles off the bar so they don't get under the chain and mangle it... and then fit the bar in place and make sure I made the cut at the right position and I can use this 36" bar on either my echo 900 or the 775d.


775d got its own thread, spent the morning before work and my lunch hr tinkering with it. It stalls when rotated when cold... but after I put the chain on it and did a cut I discovered that it doesn't stall when it's warmed up... so I'm eager to use it a bit.

So now I've got the 775d and the cs900 to play with, and a carb rebuild on deck for the super xl. And when I have time, some more milling for my g070.

 

[fields_mj]

FWIW, a cheap option for drilling ONE hole through a piece of hardened steel is to use a concrete bit. You'll destroy the bit, but it will cut a hole. Personally, I keep a couple of cobalt and carbide bits in my tool box but I've done a fair amount of metal work (machining) in the past.

 

[sliceoflife]

Thanks for the recommendation. I may be drilling a bar soon for an aux oiler input, so I'll keep it in mind.

So updates... dropped the cs900 evl muffler off with my friend's son so he can weld it if he gets the chance... but have the saw running with hackjob muffler currently. Running about the same as before the swap after some tuning. Comparing it to the 775d (3 more cc) with a 27inch bar on the echo and a 36 inch on the 775d... the echo feels quite underpowered (Despite having a lot more compression based on the effort required to pull)... thinking that the chain still may be a problem... will work on it some more and see if it helps... hesitate to buy a new chain because the bar is likely going to be replaced soon.


Once I get a new bar and chain on it and put the original muffler back on, if it's not performing more in line with what I'm expecting, may get rid of it to an echo collector. Seems some guys love these things, but frankly, I'm already much more impressed with the 775d and it's 60 years old.


775d is fun. 36" full chisel chain, it mowed through some 24" diameter maple logs... cut off three cookies in seconds. Bar oil tank seems to have a pretty bad leak though.

Still very busy with work so may not get my g070 or the super xl back in action until the end of the month.

 

[sliceoflife]

So I keep going back to filing the chain seen here: https://www.arboristsite.com/threads/so-bought-a-chinese-saw-holz-g070.364894/post-7998323 on the echo, gutting the teeth out a little more and then trying another slab and it always feels like it's improved a touch over the last time, but it's still milling at less than half the rate of my g070. I've tuned it up and I feel like I've got the saw running as good as I can... at this point I can only think the chain is just not very effective.

It may be all in my head... but it seems to me like it cuts reasonably fast at the start of the log... but after 1-2 ft of milling, it slows down a ton... almost like the chain lost hardening at some point and is rapidly dulling in the log.... but the teeth still feel sharp to the touch even when I finish the slab... so that doesn't make sense. My guess would be the angle of approach I can take at the start of a slab just lets the saw feed itself better.

I'm wondering if maybe I'm not using the depth gauge tool correctly, because it is looking like the depth gauges are too low if anything; but based on what I've read online, the behavior I'm seeing is more like the depth gauges are too high. (It's not bogging down at all; it's just cutting really, really slow). I've looked at tons of videos and I'm doing what I'm seeing in the videos; but the rakers are nowhere near sticking proud in the checking tool... in most cases they're a mm or two below it.


To give you an impression of how it acts in the cut... It 4 strokes unless I lean into the mill HARD to force it into the log... and it's tuned almost as High/Lean as it'll go... AND the saw doesn't bog at all even with me leaning in that much. By the end of the slab my arm is tired from pushing the mill along (I will be putting a pulley on it at some point, but currently I push at the handle). It's behaving like the teeth are just barely scraping the surface of log and not really biting anywhere near enough material... or at times just running right across the surface without digging in much at all.

I'd assume the fix for this is to reduce the sharpening angle (move back to 15-20 degrees maybe? Im at 10 now)... or lower the rakers, but like I said, unless Im using the depth gauge tool completely wrong, the rakers are too low if anything.


I've got a replacement bar and chain for it here... so I may just change it out and see if a fresh chain fixes the problem... but I would be curious if anyone has any insight on what could cause it to behave like this.

 

[sliceoflife]

So took the g070 out for a couple slabs... it's like a dream after pushing that Cs900 through the slab... At least 2x as fast... maybe 3x.

When I started it up, it would stall when I gave it some throttle. Turning the H down a tiny bit fixed it and it ran perfect... I assume the governor was tripping and choking out the saw?

 

[sean donato]

Grab a few carbide drill bits for holes in the bar. Don't get too eager to push as they will snap off. Same material as a good concrete bit but are made for drilling hard steels. I typically get them off Amazon. I keep a few different sizes around and they have come in handy many times.
It's a shame the 394xp deal fell apart for you, I have one I picked up years ago for milling. Had a bad top end, converted to a 395xp topend. Good 394xp top ends are hard to come by for reasonable money. Does a very nice job. Have milled 34" oak with it, it's a painfully slow go. Get a hand winch set up, you'll never go back to pushing through a slab again. Cousin got a band saw mill and lives down the street a few miles so I haven't milled since with it. Sucks for felling, the 390xp handles much better....
On the chain note, I never bothered to worry about milling chain or changing off the 25-30* top plate angle. It's called rough cut for a reason, and I like the toothy finish. I did find skip tooth was easier to deal with and lasted about as long as full comp before touch ups. Ymmv depending on brand of chain.
Best of luck with the 900evl, parts suck to find for the models that wernt real popular. Hazard of old saws I guess.
I'm curious if you ever checked the 070 for leaks? Idle should hold pretty steady once it's warmed up, and you shouldn't have to fiddle with the carb too much. Something just seems off there. Govenor issue possibly?

 

[sliceoflife]

As it breaks in more it seems to be improving some... I dont have the equipment to do pressure or vacuum tests, unfortunately.

 

[sean donato]

Just need a cheap mity vac off Amazon and some block off plates. Easy enough to make. With the stuff your playing with your going to need to be able to test them out properly. Saves a lot of hassle in the long run. The mity vac knock offs are very economical.

 

[J D]

So I keep going back to filing the chain seen here: https://www.arboristsite.com/threads/so-bought-a-chinese-saw-holz-g070.364894/post-7998323 on the echo, gutting the teeth out a little more and then trying another slab and it always feels like it's improved a touch over the last time, but it's still milling at less than half the rate of my g070. I've tuned it up and I feel like I've got the saw running as good as I can... at this point I can only think the chain is just not very effective.

It may be all in my head... but it seems to me like it cuts reasonably fast at the start of the log... but after 1-2 ft of milling, it slows down a ton... almost like the chain lost hardening at some point and is rapidly dulling in the log.... but the teeth still feel sharp to the touch even when I finish the slab... so that doesn't make sense. My guess would be the angle of approach I can take at the start of a slab just lets the saw feed itself better.

I'm wondering if maybe I'm not using the depth gauge tool correctly, because it is looking like the depth gauges are too low if anything; but based on what I've read online, the behavior I'm seeing is more like the depth gauges are too high. (It's not bogging down at all; it's just cutting really, really slow). I've looked at tons of videos and I'm doing what I'm seeing in the videos; but the rakers are nowhere near sticking proud in the checking tool... in most cases they're a mm or two below it.


To give you an impression of how it acts in the cut... It 4 strokes unless I lean into the mill HARD to force it into the log... and it's tuned almost as High/Lean as it'll go... AND the saw doesn't bog at all even with me leaning in that much. By the end of the slab my arm is tired from pushing the mill along (I will be putting a pulley on it at some point, but currently I push at the handle). It's behaving like the teeth are just barely scraping the surface of log and not really biting anywhere near enough material... or at times just running right across the surface without digging in much at all.

I'd assume the fix for this is to reduce the sharpening angle (move back to 15-20 degrees maybe? Im at 10 now)... or lower the rakers, but like I said, unless Im using the depth gauge tool completely wrong, the rakers are too low if anything.


I've got a replacement bar and chain for it here... so I may just change it out and see if a fresh chain fixes the problem... but I would be curious if anyone has any insight on what could cause it to behave like this.

Pictures... nice clear close up pictures of the chain looking at the cutters from different angles.
You may be right about the chain hardness, if someone has been overzealous on a bench grinder it can ruin the hardness of the cutters. More often it is a case of the cutters not being fully sharpened... an "almost sharp" chain will dull far quicker than a properly sharpened one

 

[sliceoflife]

Heres pictures. Red isn't rust. It's oxidized/polymerized oil.

 

[sliceoflife]

 

[J D]

Some cutters look to need filing back further (to the red line) to remove the damage completely. Failure to do this will cause the chain to become completely dull again very quickly.

You also need more top plate cutting angle or "hook". Along with correct raker height this will make a big difference in how well the chain feeds when cutting end grain.

 

[J D]

Here's a good example posted by another member not too long ago. It's not ground for milling but still has a good hook & clean chisel edge

 

[sliceoflife]

Thanks... So push it back more, be careful to keep the file straight/angle consistent and get a clean edge line and maybe drop down to 13/64" file* (from 7/32")?


Changing the bar ain't happening just yet... my .058 36" bar that the seller listed based on specs someone had written on the bar in sharpie turned out to be a .050 38" (or at least 119DL not 115DL) bar... so I'll sharpen it up one more time real carefully and see what I get. My luck your advice will fix it right before the replacement chain gets here, but it'll be good to at least understand and see in action what I've been doing wrong.


*Just googled to see if this was a good idea/the correct solution based on your suggestion I needed more hook, and found this quote: "Regardless what type of 72 chain it is, it always takes a 7/32" file, 13/64" file when the cutters are filed below 1/2 cutter length." Makes sense to me... and would explain why I felt like the file was too proud when sharpening... looks well below 1/2 cutter length, right?

 

[sliceoflife]

So it's definitely looking like it was the chain that was the problem. 38 inch bar and chain on there and I didn't want to put it into anything big and put a ton of load on the saw until I ran it and made sure it was okay with pulling that size chain but it ripped through 8 ft of 12-in diameter slab in about a minute..


I did grind back the teeth of the old chain like you recommended, so at some point I'll throw that bar back on there and see if it fixed the problem... but since the new chain got here today I figured I'd just go right to it to make sure it was something I wanted to run on that saw... and it looks good. The mashed up muffler is hanging on for dear life... so I hope the stock muffler gets welded soon and can go back on.

 

[sliceoflife]

Got an aux oiler installed on the 775d's bar so I can mill with it and dont need to worry about the manual oiler leaking now. Hoping to do a slab or two tomorrow.

 

[sliceoflife]

So I swear I couldn't find the part I needed for my echo cs-900evl muffler... but ereplacementparts has it in stock now... no clue how I missed it... so $25 later my replacement is en route.

 

[sliceoflife]

Took the 775d out and did one quick slab.

It works well.. cuts off the slab a little slower than the echo did (same size slab)... and once when I fed it too fast, the chain stopped (clutch slippage I assume?)

I do need to take some slack out of the aux oiler feed tube... bubbles caused pauses in the drip cause it had some loops... and then I need to fine tune the drip valve setting... once I got the bubbles out, it fed a quart of oil in about 30 seconds.

All in all it took some work, but seems like it's a pretty decent 95CC, 36" milling saw. It does still eventually gurgle out if I leave it on its side idling (even hot)... but took 1-2 minutes of no attention, just laying there on idle while I played with the oiler.


Cap leaks gas slowly when laying on its side on idle as well.. so I'll keep my eyes open for a replacement cap/gasket.


Next project is mounting the pulley to the mill.