When I moved to my new shop, one of the first investments was in a Pro Bandsaw, unless to have won the lottery you can forget named Brands here in Colombia, as they have to be imported, and the import duty can be 200% or more, more than the cost of the tool, so I bought a commercial bandsaw from a local manufacturer.
From the word go the problem with drift was horrendous, I tried everything to resolve it, but nothing worked, leaving only one option, and that was to contact the manufacturer, because there was only a top blade guide on the saw, no lower one.
They replied that none of their saws have a lower guide, but if I wanted to take it back, they would fit one for me...at a price!!
I thought about it long and hard and decided to try to make my own guide.Originally I planned to make it out of hardwood, but then changed my mind and went with a metal strap
with the aid of my bench vise and some brute force, I got what I wanted.
I then turned out my Oddments bin and found the rest of the bits I needed, 2 x 5/16" bearings, 2 x 5/16" bolts and locking nuts, also 4 x washers. I then drilled the new guide to attach it to the saw frame, and cut one hole in the section for the bearings, having got that hole, I then cut a slot so the bearing could be adjusted, I did this using my grinder with a cutting disc, I was a bit apprehensive of this, because, muck it up and I was back to square one. but it went fine. and the bearing sat in place.
That done I attached my new guide to the saw, and gave it a trial
It may not be the right size, and how long it will last, I don't know, but for now the difference is amazing, there is very little drift.