Understanding Sawmill Guides and Adjustments

Practical Tips On Understanding Bandsaw Blade Guides And Adjustments

As we work and talk with sawyers around the country we find many things that need to be discussed and explained to help their portable sawmills run fast and accurate. One thing that ranks near the top of this list is to understand bandsaw blade guides and make proper adjustments.

If your guides are not in tip-top condition then they cannot do the job that they are designed to do.

There are just a few types of guides that are common in the thin kerf industry. I want to mention each of them and tell you what our experience has been.

1. “Greaseable Bandsaw Blade Roller guides”
This type guide is our preference and is the kind we make and use. After trying several different types we have come to determine that bandsaw blade roller guides are the best.

It has a hard outer shell that rolls against the bandsaw blade. Inside it has two bearings with a 1/2” inside diameter hole so that it can go on a 1/2” arbor shaft. We make our roller guides so that they can be greased and we suggest that you grease them twice a day.

There are some bandsaw blade guides on the market much like the ones that we make but they are not greaseable. Watch out for these! We have customers on a fairly regular basis that say they get much longer life out of roller guides that can be greased.

This is very important because when bearings go out in a roller guide, it locks up. In about 30 seconds, with the blade rubbing in one spot, it will cause a flat side to develop on the roller and then the roller is no good.

When greasing bandsaw blade roller guides we suggest that you grease in the middle of the day and then at the end of the day. It is especially important to grease at the end of the day because after the rollers run for a while they are hot. Then when you get through cutting and they cool down they can actually draw the lubricant you are using into the bearing. This is usually water or diesel fuel. As it sits there all night, over the weekend, or longer it causes either a pitting of rust on the ball in the bearing or dilutes the grease therefore it’s not properly lubricated for your next run.

Another thing that we do to make sure we offer you the best roller guide is that we take special care and grind each one to perfection. The advantage of grinding is that it makes sure no vibration will be coming from the roller guide and transferring into the blade. We have found when rollers are out of round (even 5 to 10 thousandths) it can cause premature blade breakage.

First they cause a vibration, which is one major culprit that can be involved in blade breakage. Another thing that’s very critical about the roller being out of round is it can actually “hammer” a curve into the bandsaw blade. If you’ve read the previous article that Tim wrote about curvature in a bandsaw blade you know and have probably experienced curvature and what a problem it can be.

One more thing about this type roller guide, it has a flange on the back of it that is part of the hardened shell. It all turns together and therefore it can’t get a grove worn into it. There are some guide systems that use a back up bearing. This is a problem because the blade runs in one spot against the bearing and wears a grove into it.

2. Another type roller guide that is available is the “bearing type with no hard shell covering.”
It usually has two bearings that act as the roller guide and then a back up bearing that turns with the blade as you cut. There are a couple of problems with this type system. Usually the bearings aren’t greaseable and therefore don’t last as long as they should. The other thing as I have already mentioned above, is that, the back up bearing will get a groove cut in it and this causes damage to the blade which causes early breakage.

3. A third type guide is the “sandwich type” guide.
It actually holds the bandsaw blade to guide it. This type guide is most often used on resaws and there is a place for this type of guide. A lot of times on a resaw the most important thing that an individual wants is production more than long blade life.

Also they are usually cutting only 6" to 8". In this application the sandwich type guide can be a good choice. However, on the sawmill where you are cutting logs you need wider cuts and longer blade life. Sandwich type guides are not the best choice. We have found that the roller guides work the best. With all this said we still find in a lot of applications that roller guides still work better, especially if you are running 1 or 2 resaws and are not pushing for the absolute highest production. You will also like them more if you want to get the longest blade life.

4. “BC Retrofit Roller Guide”
The last type bandsaw blade guide that we will discuss is a hybrid that we have come up with. It combines the best of both worlds. We have combined the roller guide with what we call a bottom control guide. This is the same roller we first talked about but it has a carbide guide underneath the blade so that if the blade tries to take a dive or deviate from the cut it will catch it.

The beauty of this roller guide system is that the bottom control guide is not touching the blade all the time. It is set up to run 5 to 8 thousandths below the blade. This way you are not causing extra heat and stress to the blade all the time. Only occasionally when you hit a knot or a bad spot will the blade touch the bottom guide. Once the blade is through the bad spot then it doesn’t touch the bottom guide any more. This allows you to saw with confidence at a higher rate of speed knowing that the blade won’t take a dive deep into the log.

Also if your blade is getting dull or you hit something in the log, most often you will be able to ease on through the cut and not get stuck in the middle of a cut. This alone makes these bandsaw blade guides worth the money because of the time saved. To check out our roller guides and accessories be sure to visit our online store. You can click on your "back" browser button to return to this article when done.

Since we have incorporated this special system we find that it satisfies the need of both sawmills and resaws. You have the roller on top of the bandsaw blade that is more forgiving to the blade and the bottom control beneath the blade for just when it is needed. This extends the life of the blade and allows faster feed speeds.

Adjustment of Bandsaw Blade Sandwich Guides

How to adjust the roller guide properly is just as important as which roller guide to use. We don’t sell the regular 'sandwich type' guide (also known as 'Block Guides') but I will give you some pointers on how to adjust it. This will universal and can be applied for guides such as Carter Guides, or the types of guides used on Baker sawmills.

Ultimately you need to follow the manufacture's guide lines. For the sandwich guides to work the blade must be running parallel with the belt or log bed. To do this right the band wheels must be able to be tilted to make the blade run parallel. To check this you need a blade alignment tool that will clamp to the blade. We offer this tool at our online store.

Many people try to use a level to get the blade parallel. This will not work. You can possibly use the straight edge on the level to measure from but you cannot use the bubble.

There are too many factors that will cause it not to be right. The machine may not be perfectly level to begin with. Also if you are trying to go by a bubble you are guessing at how much to adjust. The only accurate way to do this is with a blade alignment tool and measure down to the bed (or belt) on each end of the tool and adjust it until it measures the same on each end.

Now that your blade is parallel with your bed you can bring your sandwich guides back against your blade according to your manufactures specifications. You will also need to be able to make sure that you don’t cause the blade to move out of position when you bring your guides against it.

Adjustment of Bandsaw Blade Roller Guides

The adjustment for the roller type guides is done a little bit different. We like to have the band saw wheel on a horizontal sawmill tilted forward at the top about 1/16 in. Measure to a common place on the frame that holds the band wheel. Make sure the wheel is tilted 1/16” but not over 1/8”. It is best to check your measurement with your blade tensioned up.

First you need to put your blade on and tension it up. Now make sure that the rollers are off of the blade. Then start on the stationary guide side. Bring that roller down to the blade. Once it touches push the roller down another 1/4 of an inch. This is called down pressure. If you have everything running right you might be able to run with just 1/8 inch down pressure.

To begin with I like the 1/4” because it guarantees that I am able to control the blade. Some people like even as much as 3/8” down pressure. After I have down pressure then I put the alignment gauge on the blade at the stationary side. Put something straight on the bed of your sawmill (a square tubing, the straight side of a level, even a cant if it is not bowed) with the blade a few inches above the straight edge, measure down from the front and back end of the blade tool.

The readings need to be the same. If they aren’t, adjust the top or bottom tilt adjuster bolt until the alignment tool is parallel to the log bed. After you get the stationary guide adjusted go to your moveable guide and do the same thing that you just did with the stationary guide.

Before I adjust the tilt and down pressure I like to move the moveable guide to the position where most of the logs are sawn. If there is any variation in the measurement from the blade tool let that be up against the roller guide rather than down. This will guarantee that the blade will have pressure against the roller instead of sawing away from it or consistently pulling against the bottom control guide. Again the goal is to be perfectly parallel but if any variation even 1/64” let that be toward the roller guide.

Maybe this information will be helpful to you. You need always be sure that the guides and their adjustments are correct. When you have this and put on a good sharp blade then you should cut accurate lumber. If you are having problems in this area give our greaseable roller guides a try. The results you get will get you excited!

Let's go make some sawdust,

Co-Owner CooksSaw.com
Leaders in Bandsaw Technology!