circle saw blade heating up

mdrhom1 · October 14, 2013, 09:13:41 PM

been a while since my last post been trying to get property fenced in and i finally got it done . i set my sights to get some trees sawed so i fired up the old turner mill and started with a few big oaks about 20 inch dia i made about 6 cuts 2 x 12 and saw started cupping and was hot so i stopped and let it cool .does any one have any suggestions, will dull bits cause heating and cupping.
also not sure what bits to buy or where. my shanks have 3x9 on them all but 2 and they have 3x10 on them i need to order bits , tool to change bits swage tool and files but not sure where or what to buy also whether or not to get a file guide or just sharpen by hand thanks guys

postville · October 14, 2013, 09:39:23 PM

Not enough set, track crooked, dull teeth, guides not set right......
Everything has to be right. Also look at the sawdust- is it fine or chips? You want chips that will stay in the gullet.

dgdrls · October 14, 2013, 09:47:47 PM

there is a variety of reasons a blade will heat,
sounds like its getting hot on the rim??

If you can, find a copy of Stan Lundstrum's guide "Circular Sawmills and their Efficient Operation"
Its typically available on Line as a PDF, however the Gov't shutdown may cause you some grief
if you link the Forest service website.

Possum Creek · October 14, 2013, 09:54:56 PM

I would change the teeth first and see if it helps before I made any other adjustments they are not hard to get and dull teeth can cause lots of problems. PC

lyle niemi · October 14, 2013, 10:07:04 PM

sharpen your teeth to start with then go from there

mdrhom1 · October 14, 2013, 10:21:37 PM

thanks guy the saw is throwing dust instead of chips so i thought maybe dull. i will try hand filing tomorrow, but i still need to find bits , saw tool , swage tool and maybe a file guide or a sharpener but really dont know what to get thanks again. also i tryed sawing again today and it started heating up at the collars after only 2 cuts but i still think dull

lyle niemi · October 14, 2013, 10:27:50 PM

Quote from: mdrhom1 on October 14, 2013, 10:21:37 PM
thanks guy the saw is throwing dust instead of chips so i thought maybe dull. i will try hand filing tomorrow, but i still need to find bits , saw tool , swage tool and maybe a file guide or a sharpener but really dont know what to get thanks again. also i tryed sawing again today and it started heating up at the collars after only 2 cuts but i still think dull

If you heated the blade to much it might need rehammering

Ron Wenrich · October 15, 2013, 05:44:05 AM

Most problems arise from the teeth. If they're dull, it will heat the blade because most guys don't adjust their feed rates as their saws dull. Pushing harder than your saw can handle it will heat the blade. If you're asking about dull teeth, chances are its past the point of needing sharpened.

Menominee Saw is a sponsor here on the forum. Click on their button on the left hand side. Talk to them, and they'll be able to send you teeth, files and about anything else you need.

Make sure you have your saw sharpened correctly. Just sitting behind the saw and putting an edge on it isn't enough. The teeth have to be straight, the corners need to be sharp, and the angle needs to be right. Too often hand filers will allow the angle to get to be too blunt. It will cause your saw to not cut and to heat up, even though the saw is sharp. When in doubt, toss the teeth and put in new ones.

Lundstrum's book: http://www.woodweb.com/knowledge_base_images/zp/circsaw.pdf

dblair · October 15, 2013, 08:35:33 AM

don't want those guides to touch the blade , just about a 1/64 clearance when running would do it .

mdrhom1 · October 18, 2013, 08:46:24 PM

thanks guys i swaged the bits and hand filed made several cuts and cool as can be . i still have to decide on bits the saw has standall in it now but eveyrbody say they dont like them. i got lucky a sawmiller near by gave me a swage tool and a shank tool he also dont like standall. now just need a sharpener another decision to make they are pricey , i have been a machinist for more years than i can remember and know that after a while the cutting angle will change theres just no way to be consistant by hand .

beenthere · October 18, 2013, 08:58:31 PM

mdr
Being a machinist, maybe whip something together that would guide a file at the right angle straight across the tooth. That is a trade that would be a great one to have under one's belt.

lyle niemi · October 18, 2013, 09:03:09 PM

Quote from: mdrhom1 on October 18, 2013, 08:46:24 PM
thanks guys i swaged the bits and hand filed made several cuts and cool as can be . i still have to decide on bits the saw has standall in it now but eveyrbody say they dont like them. i got lucky a sawmiller near by gave me a swage tool and a shank tool he also dont like standall. now just need a sharpener another decision to make they are pricey , i have been a machinist for more years than i can remember and know that after a while the cutting angle will change theres just no way to be consistant by hand .

I've been useing my air die grinder with a 3 inch wheel on it, I can get the angles pretty close. I just bought a jockey grinder but have not used it yet

mdrhom1 · October 18, 2013, 09:20:06 PM

i have been considering making my own sharpener , it would be really nice to duplicate a jocky grinder. at best not including the drill theres about 25.00 or so dollars in material, the price is really high for what you get but then again its not like there selling 1000s a month you know supply and demand theres more supply than demand. i havent thought about an air die grinder i have several are you using an abrasive disk or a thin grinding rock on an arbor thanks guys

ddcuning · October 19, 2013, 08:55:53 PM

Ironically, I was getting on line with regards to the same subject. I have carbide teeth in but this is first sawing we have done with the mill since we completed the restoration. The blade is cupping and getting a hot spot about 4 inches from the mandrel. Seems hard going through the logs for just sawing poplar. I also don't have track sweeps installed yet so I think the carriage rose slightly when sawing. Also I am not reading RPM yet so I am not sure of saw speed. It didn't sound right so I sped the engine up but could not tell a difference since blade was already hot. Could speed and sawdust on track cause heating issues also? I am going to change out to steel teeth for the moment since I can sharpen those.

Dave C

beenthere · October 19, 2013, 09:48:43 PM

Cupping, called dishing I believe, is not good, nor is heat in the center. Be careful running that saw until you figure it out, as sounds like you need to get it to a saw Dr.

Ron Wenrich · October 20, 2013, 06:37:03 AM

RPM is more problematic than sawdust on the track. The sawdust shouldn't have the carriage moving much more than a fraction of an inch, unless its really caked on. It would be more noticeable in long logs than in short ones. Put a tach on the shaft to get a good reading on your RPM output.

What was the RPM that the saw is hammered for? Figure out what engine RPM you need and set it at that. You can run at too fast and that will cause your saw to lay over. Another thing to remember is feed rates. If you are bogging your mill down, your RPM will drop and your saw won't stand straight through the cut. That may cause heat. That loss of RPM could also be due to loose belts.

I never used carbide teeth. I know of a few guys that have and have had good results. But, the upkeep on these are just as important as on steel teeth. If you have a chipped tooth, that could pull your saw off line and open your saw face to where it allows the saw to heat up.

Teeth have always been more of a problem for me than other aspects of the mill. Its the first place I start, and new teeth are often the cure for many problems.

dgdrls · October 20, 2013, 09:14:59 AM

Quote from: ddcuning on October 19, 2013, 08:55:53 PM
Ironically, I was getting on line with regards to the same subject. I have carbide teeth in but this is first sawing we have done with the mill since we completed the restoration. The blade is cupping and getting a hot spot about 4 inches from the mandrel. Seems hard going through the logs for just sawing poplar. I also don't have track sweeps installed yet so I think the carriage rose slightly when sawing. Also I am not reading RPM yet so I am not sure of saw speed. It didn't sound right so I sped the engine up but could not tell a difference since blade was already hot. Could speed and sawdust on track cause heating issues also? I am going to change out to steel teeth for the moment since I can sharpen those.

Dave C

As Ron mentioned confirm RPM and make sure your not losing speed in the cut. I have read you shouldn't drop more than 50 RPM when cutting (others can speak better to this than I)

Check the lead of the blade and the mandrel bearing, hot bearing will radiate heat to the blade.

Let us know,

best
DGDrls

ddcuning · October 20, 2013, 03:33:41 PM

Thanks guys. Probably a combination of RPM and dull teeth. We installed an RPM gauge on the shaft but don't have it working properly yet. I will check bearing temp though.

According to the previous owner the blade was just hammered for 600 RPM just before I bought the saw. I may go ahead and get an engine tachometer so at least I can dial in the proper engine speed. I have seen no drop in RPM so far. Have 190hp pushing 48 teeth. I had always heard the rule of thumb is 3hp per tooth which would imply that I am over powered. We videoed the first sawing and engine seemed to stay same RPM throughout.

I have some trees coming soon so I need to get this resolved.

Dave C

Possum Creek · October 20, 2013, 04:21:24 PM

A man up the road scorched his saw pretty good the other day due to his sharpener angle. His carbide teeth looked sharp but the angle was too steep, he keeps a new tooth close by to look at now to make sure his grinder stays set right.

ddcuning · October 26, 2013, 09:05:45 PM

I ordered the foot receeder rails from D&D Sawmill Parts out of PA and in talking with them they have a book from Simmons that works through how to correct issues with heating blades so I bought one. In addition, I checked the carbide teeth very closely today and they are a mess. This is the first time I have sawed with this blade and I "assumed" the teeth were good. When I looked closely, they are at all angles. Almost look like someone cut them like a chain saw and not a one straight. A majority are angled towards the drive side of the saw blade. This is the direction that it was dishing when it overheated. Someone must have hand filed with a diamond file in the past and didn't pay much attention to detail. I should have checked this closely before sawing. The Jockey Grinder with the diamond wheel comes in on Tuesday so I will sharpen up all of the teeth and get them right for next weekend and see how that goes. I also plan to check the lead and we are getting a handheld tach to dial in the RPM.

Dave C