help on sawhead up & down travel

[bruce29]

I am in the process of building a bandmill & am at the point of motorizing the saw head to travel up & down. I plan to use a 12 volt dc motor & chain & sprockets to accomplish this but am concerned about the head drifting down after stopping it in the correct position.Does anyone have any ideas on this problem or know how other mill manufactures accomplish this?

[pineywoods]

Rig the head up-down switch to short directly across the motor when in the neutral position. Serves as an electrical brake. Been used on woodmizers for 30+ years..

[bandmiller2]

Welcome Bruce,I've probibly repeated this five times over the years but an alternative to electric is hydraulic. Drive a small hydraulic pump from the engine on the carriage use it with a hyd. motor and drum to feed, and a hyd.cylinder and wire cables to raise the saw assembly,it works for aerial ladders and bucket trucks.Electrics work but require a good alternator to keep up.

[bruce29]

what type of motor do they use? does this method of electric brake draw alot of current? AS far as using hydraulics ,I am using a seperate power unit for all other sawmill functions(log loader , turner , head travel, clamps, etc,) , but I did not want the extra expense & maintance of a hydraulic hoes carrier & the extra plumbing invoved.

[Magicman]

The shunt on the up/down motor will stop it, but really is not a brake to hold it and prevent creep.  A worm gear is the answer to prevent creep.  You can't turn a worm gear with the driven gear.

[ladylake]

The shunt on the up/down motor will stop it, but really is not a brake to hold it and prevent creep.  A worm gear is the answer to prevent creep.  You can't turn a worm gear with the driven gear.

Right, my B20 has electric up and down driven through a worm gear box, motor and gear box are 1 unit. There is no creep and the alternator on the 27HP Kohler and the Isuzu diesel that I put on keeps up just fine.  Steve