blade guides on a manual mill

[Dan_Shade]

I've mentioned it a few times before, and I keep brainstorming how to improve my blade guides.

Has anybody made a good/accurate/reliable/easy to adjust blade guide for a manual mill that will provide the downward pressure that is needed to keep the waves to a minimum in finicky wood?

I can't figure out how to keep the guide arm from racking and binding up when moving it if it is deflecting the band downward.

[highpockets]

Dan, I am not a sawyer when compared to many of the people on this forum but I have about decided that a band blade is going to walk in some cases regardless of what is done.  I recently built a new blade guide which is included in my photos.  I replaced the guide arm with a piece of 1 1/2 X 1" solid square bar.  I think the new guide did help but I have seen some walk.  I just cut a red oak log that was some 20".  In one place it had an upperward movement across a knot of about 1/16".  The thing was, the right side of the cut was much better than the left side where the knot was.  The cut was a 2 x 15" board.  The  blade actually had some twist in the face of the cut. 

What I think is that the key is a sharp blade, a decent guide and a VERY gentle approach into a knot. I can say that the better the log the better I can saw.  I think it is the nature of the beast.

[Dan_Shade]

I agree with that, but I am under the impression that a good guide can minimize the deflections.

I sawed up a few logs yesterday that had been down for a few years, they were pretty hard, and the knots were giving me fits.

[highpockets]

I do think a good guide will help, but it seems that knots, etc. just gives most folks fits.  I think if you can identify where the knot is prior to cutting, you can be very patient at that point.  I noticed a guy the the other day that had a WM. I noticed that when his saw got to a knot, it would actually stop for a moment and then continue.  He had the feed set that low.  I also noticed that he seemed to handle the knots pretty good.

[Tom]

Blade guides are to "help" control blades from catastrophic misalignment.   What actually causes the blade to cut straight is the proper set, rake, height and sharpness of the tip of the tooth.   Nothing replaces 'sharp'.   

A band with too little set will follow the grain or have problems with knots (cross grain).   If the rake is too great, the band will chatter.  If the blade is dull, you get push-off and wander.

A guide's job is not to forcibly hold the blade in alignment but to "guide" it as it attacks hard and soft areas of the log.

I can understand why racking is a problem.  It was probably a problem for the major manufacturers too.  I'm sure they have many man-hours involved in the design and manufacture of a movable blade arm.  That is where they justify their costs, not just in the materials used.

You're right, Highpockets, a sawyer plays his saw.  He listens to the engine, the blade, watches the sawdust, feels the heat and adjust the speed of attack in critical areas.   That's why a good sawyer of one of these small mills isn't just putting the blade into the wood and then walking off for a cup of coffee or conversation until the log is cut.  It takes a lot of concentration and education to learn one's saw.  It also makes it difficult to cut on another persons saw, even if they are identical in manufacture.  It' s an art as much as a science.

[mike_van]

Dan, I used linear motion pillow block bearings, i'll email you a photo later -

[Radar67]

Why not post the photo here for all to see?

Stew

[mike_van]

Stew, here's what I wind up with to post - kind of hard to see what it is -

[fat olde elf]

blade guides ?  One word answer............Cooks !!!!!!

[Tom]

Mike,
Woodmizer has used separate wheels on cams to hold their movable guide arm.  It has worked good for years, and is adjustable. 

If you get the linear bearings straight, there is no reason they shouldn't work.  Baker uses them.  Of course Baker uses flat guide plates and there is not much pressure on the bearings.   I think I would look at the distance the bearings were from one another and make them be as far apart as possible to do away with the rackng pressures.  Perhaps you have done that, I can't tell.

[mike_van]

I sent Dan the  larger photo, I just give up trying to get anything decent to post. I use irfanview, it works well for all I do [except here] -  The whole assembly you see in the photo [kind of ?]  Came from a scrap dealer that used to pick up from Kimberly Clark. I think it stuffed Huggies into bags. There are two 1" dia rods, about 30" long, they run in 4 linear bearings. My guide [ Carter] is attached to the farthest piece on the right you can see. In the middle [green shaft] there is an acme thread rod, a reversable 110v motor w/ right angle drive turns it, I can run the guide  out to 32" throat or run it in so there's 8" - thats as narrow as it goes, but i've never needed it closer. Like Tom said, with sharp well set blades, the guide is just that, gets you past the "hairy" spots in the log. 

[jpad_mi]

Dan,

Here's a couple of pics of my moveable guide arm. The blade guide is mounted on the end of a 1 1/4" square bar which slides in a homemade linear bushing assembly. This is a 14inch long piece of 2 1/2" x 1/4" wall square tube with 4pcs of 3/8" x 1" brass bushing at each end. It uses a simple jam screw on the corner of the square stock to lock it into place. It doesn't appear to deflect at all when fully extended.







Mike's setup looks great. You might also check around for a surplus ball spline.

[Tom]

Good and Clear pictures.

[RichlandSawyer]

Hi Dan,

I adjusted my guides down to put some upward pressure on them and it slides in and out like a dream.
I was deflecting the blade a good quarter inch and it glides like glass.

[thecfarm]

Same idea that I have on mine mill.Sometimes I forget to adjust it,and it comes out fine,other times,oops.Looks good.

[GF]

What I did on mine instead of laying the square tube flat like all the previous pictures show, I rotated mine 45 degrees and turned some vgroove rollers on the lathe and pressed bearings in them, I mounted two on top and two on bottom and have not had any problems.  They attach to a slot on the frame so they can be raised and lowered individually and this allow a fine tune adjustement to the deck if needed.

[arj]

Dan I  drilled a 5/16 hole on the top & side of my moveable arm, tacked a 1/4 inch nut over it and use two bolts finger tight to keep it in place. this works very well for me. I don`t move it as much as I should, but the bolts being finger tight it`s no problem. With the arm stable I get flat cuts even if there is more space between the guides than necessary
                               
                             arj

[WkndCutter]

Dan,

I know what you mean.  We have the same mills and mine drives me crazy sometimes.  I'm going to be trying some adjustments and have been looking into several new designs for the blade guides.  I think I need to push the blade down just a bit.  I'll post back after I finish cutting this weekend.

Nice pictures and plenty of great information on the previous posts.

Andy