I am hammering out the design of the mill, and wondering how people deal with the friction of the headrig going up and down the vertical parts of the carriage? I've seen on the cook's videos that many of their mills use a bushing traveling up and down a chrome shaft, and one guy on youtube had a really slick system of bearings that rode on the flat surfaces of his carriage posts. Any thoughts on what's best?
Thanks,
Mine rides on cam followers on the flat surfaces of the post. When I build mine I will use the polished rods. The thing there is there will be almost no tolerance to play with. The guides will have to be dead on for spacing. I don't like the play my mill has. I think is slows it down with the head not being rigid.
My vertical post was 1/4" thick x 2-1/2" tube square steel.
I sprayed dry graphite on the tubes thinking that I needed it.
Everything was a tight fit. The weight of the carriage was enough
to keep it from hanging up. After a while things loosen up to a
point that I added adjustment bearings to take out the play.
Everything works great now.
(https://forestryforum.com/gallery/albums/userpics/39553/Slack_adajuster~6.jpg?easyrotate_cache=1480286106)
My mill is an old TH and it has 1'' rods...If you use the head frame,it needs to be dead nuts,but then again it should be,anyhow...
What about friction in the headrig/mainbeam thing for the tensioner? The cook's guy talks about not liking the threaded rod with a torque wrench system because they sometimes 'bind out' with too much friction on the slide?
Thanks,
Quote from: wooddust on December 04, 2016, 02:40:35 PM
What about friction in the headrig/mainbeam thing for the tensioner? The cook's guy talks about not liking the threaded rod with a torque wrench system because they sometimes 'bind out' with too much friction on the slide?
Thanks,
I have a minor issue with that; no problem when tightening but when I remove the tension, I sometimes have to give it a "tap" before removing the blade. Perhaps I am just used to it but don't consider it a problem.
Quote from: Den-Den on December 04, 2016, 06:15:41 PM
Quote from: wooddust on December 04, 2016, 02:40:35 PM
What about friction in the headrig/mainbeam thing for the tensioner? The cook's guy talks about not liking the threaded rod with a torque wrench system because they sometimes 'bind out' with too much friction on the slide?
Thanks,
I have a minor issue with that; no problem when tightening but when I remove the tension, I sometimes have to give it a "tap" before removing the blade. Perhaps I am just used to it but don't consider it a problem.
Does your tension system ride steel-on-steel or are there bearings or bronze friction plates or something in there? Grease?
Thanks,
My band mill uses 1" rod and bushings pressed into a section of Shelby tube. There are grease zerks on the Shelby once or twice a year they get a few shots. No problems, but if I built another mill I would try angle iron uprights with "V" castor wheels. The angle would be attached to upright 2" square tube and adjustable. Frank C.
Does your tension system ride steel-on-steel or are there bearings or bronze friction plates or something in there? Grease?
Thanks,
[/quote]
It is steel on steel.
Den, my mill uses bronze bushings on a steel shaft. Usually steel on steel is not as good. If a band head was perfectly balanced any play would be detrimental. Most have a preload and are adjusted to cut level in that position weight forward or to the rear. Frank C.
Quote from: bandmiller2 on December 04, 2016, 08:25:15 PM
Den, my mill uses bronze bushings on a steel shaft. Usually steel on steel is not as good. If a band head was perfectly balanced any play would be detrimental. Most have a preload and are adjusted to cut level in that position weight forward or to the rear. Frank C.
Do you have an pics of this set up? is it polished rod? Also what is Shelby tube? I have had a machine shop for over 20 yrs and never heard of it.
OJ, sorry on the picture thing. Shelby tube is pipe with very thick walls its seamless drawn over a mandrel and very expensive, I used it because I had it. The rod is cold rolled steel. Frank C.
Perhaps eccentric cam followers riding against the post would work well. The ability to adjust not only the clearance but also the "tilt" of the head would be simple and advantagous. Low friction and zero clearance.
I used some UHMW pads in home-made brackets (2" x 4" x ¼" wall tube cut into C shapes). My head rig ride on the inside of a pre-welded (scrap) shelving unit frame. The gray things at the top of the picture:
(https://forestryforum.com/gallery/albums/userpics/30640/Bandsaw_Lift_gearing_3.jpg?easyrotate_cache=1436587386)
"front" side of the bracket.
(https://forestryforum.com/gallery/albums/userpics/30640/Bandsaw_Drive_1.jpg?easyrotate_cache=1436587278)
Mine is just a square tube inside a square tube that is a very sloppy fit. On the outer tube I drilled holes and welded nuts over the holes. Then I used bolts in the welded nuts to take up the slack between the two tubes.
When the engine isn't running it tends to bind but the vibrations of the engine allow it to move smoothly.
Quote from: ljohnsaw on December 05, 2016, 03:08:25 PM
I used some UHMW pads in home-made brackets (2" x 4" x ¼" wall tube cut into C shapes). My head rig ride on the inside of a pre-welded (scrap) shelving unit frame. The gray things at the top of the picture:
(https://forestryforum.com/gallery/albums/userpics/30640/Bandsaw_Lift_gearing_3.jpg?easyrotate_cache=1436587386)
"front" side of the bracket.
(https://forestryforum.com/gallery/albums/userpics/30640/Bandsaw_Drive_1.jpg?easyrotate_cache=1436587278)
What size motor do you run? Does it have enough power to pull the mill?
Quote from: bandmiller2 on December 05, 2016, 06:46:21 AM
OJ, sorry on the picture thing. Shelby tube is pipe with very thick walls its seamless drawn over a mandrel and very expensive, I used it because I had it. The rod is cold rolled steel. Frank C.
Ok DOM tube. I have quite a bit of that around. Has the Cold Rolled rod held up ok? I was thinking of polished rod but you talk about expensive!
OJ, its been 16 years and I can see no perceivable wear on the cold rolled rods. Theirs always a good coat of grease on them. Frank C.
Quote from: ozarkgem on December 05, 2016, 06:26:41 PM
Quote from: ljohnsaw on December 05, 2016, 03:08:25 PM
I used some UHMW pads in home-made brackets (2" x 4" x ¼" wall tube cut into C shapes). My head rig ride on the inside of a pre-welded (scrap) shelving unit frame. The gray things at the top of the picture:
(https://forestryforum.com/gallery/albums/userpics/30640/Bandsaw_Lift_gearing_3.jpg?easyrotate_cache=1436587386)
"front" side of the bracket.
(https://forestryforum.com/gallery/albums/userpics/30640/Bandsaw_Drive_1.jpg?easyrotate_cache=1436587278)
What size motor do you run? Does it have enough power to pull the mill?
These were the only pictures I had showing the guides. I don't have power feed, if that is what you are asking. That is Version 1.0 of my mill :D
That was a 2.25 hp DC tread mill motor. Worked ok for testing.
Version 2.0 I replaced that with a 7hp gas. Worked better and I did some "serious" cutting with that.
(https://forestryforum.com/gallery/albums/userpics/30640/Bandsaw_guard_1.jpg?easyrotate_cache=1437028874)
Current version (3.0) has a 18hp twin cylinder B&S gas engine with electric clutch. Works pretty good.
(https://forestryforum.com/gallery/albums/userpics/30640/Bandsaw_new_18hp_1.jpg?easyrotate_cache=1440740668)
What brand of clutch did you use? Is it 2 groove? Nice looking build.
Quote from: bandmiller2 on December 05, 2016, 08:04:31 PM
OJ, its been 16 years and I can see no perceivable wear on the cold rolled rods. Theirs always a good coat of grease on them. Frank C.
IF its been 16 yrs you did it right. Do you have any pics or videos of your mill?
I see you got away from using the red twist belts (junk) not
good for anything over 2 hp.
Quote from: Kbeitz on December 06, 2016, 08:55:24 AM
I see you got away from using the red twist belts (junk) not
good for anything over 2 hp.
Yep, learned my lesson!
Quote from: ozarkgem on December 06, 2016, 07:03:59 AM
What brand of clutch did you use? Is it 2 groove? Nice looking build.
I made a dual pulley for the electric. The big pulley mounted behind the tire was a twin groove - all I could find in 14" at the time. I put the twin belts on the 7hp and they fell apart. For the 18hp, I turned the twin groove 14" pulley on my mill to make it a single groove.
(https://forestryforum.com/gallery/albums/userpics/15434/P1050431-1.JPG?easyrotate_cache=1232652257)
I just used some skate board bearing to center the upper part of the slide. You really do not need much precision with the system, I just didn't want the paint to get scraped off all the time. If the blade itself moves side to side or back to front as the carriage height is adjusted it will not affect the cut as both those movements are in the direction of the cut. The only way the blade can go is up, acting against the weight of the saw frame and the blade tension. Most saw frames are way to heavy to move up due to pressure on the blade, it just bends or breaks. I saw Matt Cremona's linear bearings on his design, kinda looked like a waste of very expensive parts, and I would worry about just how much weight they can hold in a vertical application.
That little bit of side to side play will grow into big oscillations
that will give you sawing problems.