Band saw question

[muddstopper]

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]

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]

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]

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 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]

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]

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

 

[muddstopper]

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]

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]

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

 

[muddstopper]

Learn something new everyday. Did a quick search and found this site, http://www.starrett.com/docs/saw-resources/recommendations.pdf?sfvrsn=2
I plan on doing a little work on the down feed to see if I can get the feed rate more consistant and then I will throw on a new blade and see how she does.

 

[jwmorris]

Here is another one.

http://www.lenoxtools.com/Guides/LENOX Guide to Band Sawing.pdf

If everything is right you can get many thousands of parts cut from a single blade. The flip side is that you can ruin a blade making a single cut.

 

[ericher69]

Call Lenox for advice they are a wealth of knowledge-the tech on the phone would have talked for an hour if I didn't interrupt him. Very interesting topic when you get in to it with someone that knows what they are talking about.

They can guide you through feed pressures, tooth pitch for material, type of blade, blade speed etc etc.

I ordered a custom length 6/8 variable Diemaster II for my vertical saw and a similar shorter band for my 4x6 and could not be more impressed.

What a difference from the cheap 28tpi Chinese bands.

Sent from my iPhone 5s 64Gb using TractorByNet

 

[BXpanded]

There are about 3 things that can cause cut squareness problems. Down feed speed isn't one of them.
It's almost always the blade. Replace the blade and try it.
Next is blade tension. The blade needs to be tighter than you would think. If you can get the manual for your machine, it'll give some guidelines as to how tight.
Next is worn or misadjusted blade guides. The blade should be snug in the guides, no more than .001" clearance. The guides should be aligned and must hold the blade exactly vertical. Again the manual can help. Don't change these unless you actually have a reason to. It can take an hour or two to align them, even if you have some experience. The guides, whether carbide blocks or rollers, should contact the blade on their entire face. If they are worn, replace.
We use 10-14 pitch blades for everything. Larger pitch chatters on thinner materials. Thicker stuff doesn't cut as efficiently as with a larger pitch, but we don't spend time changing blades.

We have an Ellis 2000 that uses a 1" blade. I think it might be larger than your Carolina, but the set up should be similar. It runs about 4 hours per day. The cut is exactly square as long as the blade is good. You cannot tell whether or not the blade is good by looking at it. A blade will usually last for several weeks but one incident of a work piece not clamped tightly, or one piece of steel with a hard spot can ruin the blade instantly. We order 5 blades at a time and re-order as soon as we put the next-to-last new one on the machine. We order them from our welding supply house. They make the blades using Lennox blade stock and are cheaper than ordering pre-made blades.
The spring adjusts the down feed pressure. Using a fish weighing scale, raise the beam some and lower it while watching the scale. Lower the beam slowly with the feed speed completely open. The down pressure shown on the scale should be about 8 pounds just before the blade hits bottom. Again, the manual will probably give the correct reading. Too much down pressure will overstress the blade, too little will cause a slow cut and excess heating of the blade teeth.
The down feed speed doesn't matter much. It pretty much just controls how fast the blade drops to the material. Once the blade hits the material, the feed pressure, material being cut and the blade, control how fast it drops.