Band saw question

muddstopper · May 8, 2014

I recently traded for a older model Carolina bandsaw. It will cut 14x8 and uses 1in wide blades. I dont have much in it as i took it in on a trade, but I am having a problem with it cutting Sq. Cutting flat plate, laid flat, it does a good job, but widest thing I have cut has been 8in. I can take that same 8in piece of plate and lay it on edge and the saw will cut straight until it gets down to about the last inch, the cut seems to curl outward from the cut path. I am thinking it has to do with the hydraulic feed cylinder letting the blade fall faster as the saw gets lower in the cut. The little cylinder is pretty finicky about adjusting cut speed and the cut starts out pretty slow and rate of fall seems to increase the lower the blade gets toward the table. I guess i just need suggestions on how to work around or adjust the rate of cut to keep it more uniform thru out the entire cut. Also, the blade is a 14tpi and the machine came with 2 more new blades of the same tooth count. It seems to cut pretty slow, 8 min thru a 8in x1/2 in plate laid flat. Just wondering if I need to increase the blade speed, the machine has step pullies for a 3 speed, or if maybe trying a 10 or 12tpi blade.

CalG · May 8, 2014

Rule of thumb, 3 teeth in the work, so your 8 inch cut laid flat would use a much coarser toothed blade.

With that, There should be a counter balance SPRING that evens out the feed rate.

If there is not one so fitted, FIT ONE! I can't help with spring rates and leverage ratios, but have a look at some other saws and see how they go.

I've got a Famco (Armstrong- Blum) 6x12. Even with the spring, the feed pressure seems to change through the cut. But ...With a good blade, IT cuts pretty darn square.

muddstopper · May 9, 2014

Factory spring is in place. I havent tried adjusting tension, I'll give that a try and see how it works. Probably also put on one of the new blades and see if that helps, but the blade on it looks almost new. So far, I have just been cutting some scrap just to see how well it works. Machine cuts reasonably sq, its just that bird tail it leaves on tall cuts. Saw starts straight, but when it gets closer to the bottom of the cut, (about 6inches down in a 8 in cut) it just starts curving outward, leaving a bird tail. Since I probably wont be cutting that much flat stock turned up on edge, it probably wont be that big a problem, but I do worry about box tubing cuts. 3 1/2 sq tube and 2in round tube and round bar it seems sq, dont know how it will work out on larger tube.

stuckmotor · May 9, 2014

The Yahoo "4X6 Bandsaw Group" is a great resource for things like that. Many of the owners have made their own hydraulic feeds. I believe I've even seen the Carolina saw mentioned over there.

yomax4 · May 9, 2014

May be the set in the teeth on the blade. It may seem to cut straight at 1st but as it cuts it will really go off square. New blade will probably do it. Sadly with the price of blades, You may have to replace this one. blade tension can cause this too if it's too loose.

muddstopper · May 9, 2014

I think it has more to do with the changing feed rate than anything. I sprayed the spring tension screw with pbnutbaster this morning. I will try adding some tension to the spring and see how that works out and then try a new blade. From what I have read, Carolina saws dont have that good a reputation. Folks either love em or hate em. I probably wouldnt have bought it, but It was threw in on a trade and I dont really have anything in it, so its worth tinkering with. It did come with 2 new blades and thats about $100.

jwmorris · May 10, 2014

This can be time consuming work but never start with an old blade or one that is not broken in.

muddstopper · May 10, 2014

jwmorris said:
This can be time consuming work but never start with an old blade or one that is not broken in.

Never heard of breaking in a new blade, please explain

Arc weld · May 10, 2014

Very important to break in a new blade. If you don't your blade will wear out in less than half the time and you could break teeth. Basically you run the feed rate about half for the first 10 or 15 minutes of cutting. I'm sure a site like Lenox, Wikus or MK Morse could explain the break in procedure in better detail. Better bandsaw blades can make a big difference. If you break a good blade, don't throw it out. If there is a blade distributor in your area, they can weld it back together in about 5 minutes. If you buy your blades from a place with a blade welder, they usually won't charge to weld a broken blade. The reason there aren't a lot of blade welding shops around is because the good blade welders cost upwards of $250,000. Ideal blade welders are top of line. I was using one for a few month's a couple years ago. They are water cooled. The place I worked was too cheap to leave the thermostat up at night so rigged up a 1500 watt circulating heater from a vehicle to warm the coolant for the blade welder. Seems to me the 1500 watt heater defeats the purpose of trying to save money by turning the thermostat down? :confused3: The furnace would run steady for a couple hours getting the place back up to normal room temp. too.

bumperm · May 10, 2014

Also, if like most metal cutting band saws, there will be either ball bearing or hardened metal guides on each side of the blade, both above and below the cut. There are two adjustments for these guides. The fore and aft (relative to the blade), should be adjusted up close to the teeth, but not overlapping them. The guides should also be adjusted so as not to deflect the blade, but be right up snug against it on each side*.

If the guides are not snug and true, the blade will wander.

*Blades are welded and then the weld ground so it's not proud of the blade. Good idea to check the weld before installing the blade - if the weld is not flush it will hang up in the guides (and also sometimes in the cut).

bumper