October 2005

Custom Band Mill Service Mill Alignment Procedures

In the Prairie Provinces, green ash grows on riverbanks and lakeshores in association with cottonwood, Manitoba maple, American elm, bur oak, and on occasion basswood. It is often planted in shelterbelts both within and outside of its natural range due to its relatively fast growth and wide tolerance to flooding, drought, alkalinity and extreme climatic conditions.

Background

• Most band mill alignment problems are caused by a number of factors. While each factor may contribute minimally to misalignment, several factors may combine to significantly reduce the quantity and quality of mill production, as well as to make alignment extremely difficult.

Basic Mill and Saw Blade Tips

• Keep mills as original as possible. Avoid the temptation to modify or retro-fit. Minor design changes can significantly complicate mill alignment, as well as negate warranties.

• Set up band mills on "level" ground. Do not use jacks to level the bed and/or to raise wheels off the ground. Log weight and branch stubs can cause flexing of the deck. This causes head and deck misalignment.

• Minimize transporting portable mill, especially on rough roads. When transporting lock down the head.

• Always put the key in your pocket when away from the controls.

• Never operate the mill without guards.

• Check for tools, logs and other obstacles before starting saw.

• Always remove tension from the blade when not in use.

• Apply a thin coat of transmission fluid to each blade. Hang uncoiled blades on a wall. Tag every blade and record each time they are sharpened and set.

• Change blades when dull, approximately every hour.

• Keep a log book and record all mill service and alignment work, as well as log and lumber production.

Ribbon Blade Test

• Set aside a new, sharpened and set "ribbon" blade. Use only to determine if you have a blade or alignment problem.

• Make one cut each with the "ribbon" and production blades

• If there is a difference in the quality of cut, there is a blade problem. ACTION: Sharpen and set production blades.

• If there is no difference in the quality of the cut, there is an alignment problem. ACTION: Align the mill

Mill Alignment Tips

• Always align the mill head at the same location on the deck - ie: the Number 1 Rail or Home location.

• Always make small changes or fine adjustments and check the results.

General Mill Alignment Sequence

(Mill alignment differs for each brand of mill)

1. Confirm that the mill is in good mechanical condition, ie: wheels, bearings, belts, etc.

2. Compare the "ribbon" blade lumber to production blade lumber.

3. Install the "ribbon" blade. Move the head to the "Home" or "Number 1 Rail".

4. Back off blade restrictor system, guides and tension.

5. Align wheels horizontally using a string.

6. Align wheels vertically with a plumb line, then recheck horizontal alignment.

7. Check wheel bands, position blade and roughly set tension. Wheel bands should be "loose".

8. Replace guards, start mill and run band wheels at operating R.P.M. Adjust tension using the flutter test - ie: loosen tension until blade flutters, then tighten just enough to eliminate flutter.

9. Stop saw and check blade tracking. If blade is straight and running true, go to Step 10. If blade is not running true, go back to Step 5.

10. Adjust tracking, so the blade runs parallel to the bed. Lower the head and use a gapping tool (a socket or combination wrench) to level the head to the bed.

11. Bring blade guide system back into play. Adjust deflection to both guides before tightening.

12. Use a straight edge to set an equal angle of lead for blade guide rollers or blocks. NOTE: Ideally, the blade should not contact rear restrictors. If you choose to allow the blade to contact the restrictors, make sure it contacts the restrictors equally, but does not run against them continuously. Watch blades for mushrooming.

13. Adjust thickness markers, ie: inch and quarter scale.

14. Install a production blade and saw for three hours. Make sure that the blade cuts on the level.

15. After three hours sawing, go to Step 3 and repeat the alignment process.

16. Learn the feel and sound of your mill when it is aligned and sawing with sharpened and set blades. If the feel or sound of the mill changes or if the quality of cut changes from the norm, re-align by making fine adjustments. A mill should only need to be aligned once a year.

The Manitoba Agro Woodlot program is part of the federal-provincial Agricultural Policy Framework (APF).

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