Friday, August 17, 2018

Seat Of My Pants Engineering - Corrections

So I started yesterday by reinstalling the carriage on the mill frame. I soon found out that my large blade guides were going to increase the minimum thickness of the last board without raising it off the bunks with a filler board. I proceeded to trim the bottom bearing mounts and modified the mounting bracket so that the bearing assembly was 1 1/2" lower than the rest of the bracket to prevent any possible hang-ups. The result the 2" bearing and 1" mount are the only thing lower than the blade. This increases my last cut to 2" thickness. A 1 1/2" filler board under the last cut will bring my minimum last cut to 1/2". Easy. I will need to raise the stops on the slide head to avoid running the bottom bearings into the carriage in a moment of inattention, ha' ha.

Here's how commercial mills get around this problem. There is no bottom bearing, instead there is a grooved flat surface. It is only right that they include lubrication and cooling engineered in. I suspect these produce more heat from friction and wear on the blade, without it.

So that was my morning yesterday. I spent the rest of the day making some finer adjustments and playing with the drives on the mill. Ideally this picture is the operating position. All operating functions, short of loading and turning the log, can be done from this location, even unloading a board is only a step away. When the electrical is done I hope to install extensions to the two winch controllers, so I can move around and observe the cuts as they progress.

So I made some fine adjustments to the sliding head, got the wheels perfectly parallel to each other and after setting the blade guides with good tension on the blade, I adjusted the lift cables so the blade was perfectly parallel to the carriage bunks. 

During this time I had both winches connected to the same battery I had used the previous day. I run the head slide up and down and the carriage end to end all afternoon, (I'm going to enjoy playing with this ha,ha.) without any noticeable loss of power. With 2 batteries and the small charging contribution from the engine system, a full day of sawing shouldn't be a problem.

Wednesday, August 15, 2018

Installed The Powered Height Adjustment

So productive day today, made a correction, got 5 band sawmill blades, got the chance to tell the norths worst delivery service where to go and how to get there, ha, ha. Long story, I'll not go there. Installed the height adjustment using another ATV winch and tested it out.

So the first picture is the extension and new hand wheel that I installed on the blade tension assembly, the previous installation was to short to extend beyond the future guard and I found this very heavy hand wheel. I had considered scrapping it a couple of times, because I couldn't find a use for such a heavy hand wheel, but turns out this is a perfect application for it. I threaded it 3/4" pipe thread and installed it with a 3/4" pipe extension.

In the same picture you can see one of the new blades. It is a 1 1/4" carbon silicon blade with 7/8" tooth spacing, and surgically sharp, (I drew blood just uncoiling it, ha ha.) made in Germany.

So on to the lift winch. This is another 1500 lb. ATV winch. A whole $40 about 10 years ago. To get it to work I had to make one modification. Since it is winding or unwinding two separate cables at the same time and rate, I had to drill a second retainer hole and set screw threading, at the opposite end and side of the winch drum. One cable feeds from the top and the other from the bottom so that when the winch operates, both cables are either winding or unwinding. The angle to the pulleys keeps the cable well spaced and top to bottom is less than one full rap on the drum, this keeps the speed consistent and even on both sides. I bolted the winch to the head, instead of welding, until I am certain this is going to work out.

Here is the pulley mounting, you can see the angle that keeps the cable well separated on the winch drum.

A wider picture of the winch and both pulleys. The cable passes through two 3/4" holes drilled through the head frame.

So we are ready to try it out. I pulled out one of the two marine batteries I recently got for this purpose, and connected up the winch.

So here we go ready to try it out. Here at the bottom slide locks still on and the cables just snugged up.

Released the slide locks and raised the cutting head to the half way point. Raised effortlessly, one side seemed to grab a bit occasionally. Checked the post and cleaned up a bit of weld spatter I found.

Continued to raise the cutting head to the top of its travel, traveled easy and steady. Lowering was faster and very steady. I have never seen this type of set up before, so I wasn't sure it was going to work. I have yet to see how battery life is going to hold up, but so far this works great.

When I put it into use a light greasing of the head posts will make it even smoother and less demanding on the batteries. This is another post where video would have been nice, maybe one day.

Tuesday, August 14, 2018

Head Slide Locks Installed

So you may recall, I was considering a linkage assembly for the head slide locks. However I would have been limited to a little more than a 1/4 turn. I decided a chain and sprocket assembly would work better and be less problematic.

Years ago I got a number of surplus double sprockets from Princess Auto, I cut one in half and welded each sprocket to 1/2" bolts. The bolt at the operator side is 4" long , I cut the head off after welding the sprocket to the bolt and installed a handle I got out of the old Delta parts box.

It was quite tight to start with, a couple squirts of thick gear oil helped a lot.

I started the remote bolt lock 1/2 a turn first, before I started the the handle lock. this to insure the remote side locks first, a good tug on the handle snugs up both sides.

Guides Complete

So it took a day and a half but I got the guides complete. As usual I overbuilt, in addition to the eccentric bearings the brackets are completely adjustable. I once read a forum discussion where one commenter stated that a properly set-up and running mill doesn't even need guides. That may be true in theory, but I doubt he ever run his mill without guides.

So here are some pictures of the completed guides. Here the guides and the brackets they fit into.

Another view.

Here installed in the brackets.

Another view. 

Here the brackets are installed on the guide arms and set to the maximum cut, 28" between guides. That will square up a 32" diameter log, not that I even have a log that big to square up, ha, ha.

Here a close up of one guide. I could gain another inch between guides by trimming the guide leading edge, but I have no need for more capacity and I would rather protect the bearings from getting run into the log.

Another picture of both guides pulled in.

Sunday, August 12, 2018

An Easy Positioner And Two Horses For The Metal Shop

So taking a break from the welding this weekend I thought it only right I upload a few quick welding projects. First is probably the worlds most easy positioner. I have had this file for a very long time, so I can,t remember where I found it. The positioner is designed for light work. Like the one I built a few years ago, it is fully adjustable, however this one mounts to a table.

Don't forget to click twice depending on your screen size for best view.

The next two projects are something I could have used in my current project. Light wood horses or roller stands are ok for woodworking or light shop work but for large welding projects and handling heavy steal sections these two heavy welded pipe and angle iron horses are just the thing.

The Lincoln Arc Welding Foundation published a book called "Welding Plans For Farm And School Shop". Couldn't find the publication date anywhere but it looks like it came from the 60's. There are a handful of other interesting projects in this book that I will try to remember to upload, in the future.

Wood Turning Visualized Part 2

So here is part 2 of "Wood Turning Visualized"  that I promised last week. As mentioned before, if you are new to wood turning or thinking of getting started in this satisfying hobby, this book is the practical, hands on, instructor you need.

The 48 pages in part 2 starts of with safety precautions while using the lathe, takes you through the basics of spindle and faceplate turning,  shows you some jigs and aids to make your turning more productive, and takes you into some practice turnings and projects. Enjoy.

To download "Wood Turning Visualized" Part 2 go to my Books - Free Downloads page. # 56 - Part 2 - 8 MB - pdf.

Look for Part 3 next weekend.

Friday, August 10, 2018

Eccentric Guide Bearing Adjustment

So I got into the shop this afternoon and put together the bearings for the blade guides. I decided to make them eccentrically adjustable.This makes them easy to mount and just as easy to adjust.

In the first picture are all the parts for each bearing The 2 1/2"- 3/8" bolt has the thread extended 3/4" more than they normally come with, and the 20 mm bearing insert is drilled 3/8" offset to give the bearing eccentric adjustment. I will use this insert as the drill guide to make the 6 I need.

Here I assembled one with the test insert. Large fender washers are bolted tight to inside bearing race and center insert, mounting to the guide arm is between the back washer and lock washer. To adjust the bearing, hold the bearing bolt with a wrench and loosen the back nut, Turn the bolt left or right to increase or decrease the bearing clearance to the blade and re-tighten the back nut, done.

Here a test mounting to a scrap piece of angle. Half a turn of the bolt will adjust the bearing 1/4".

So using the test piece as a drill guide I made up the 6 inserts I need.

And here are the guides I need, all assembled ready to install. The washer and nut order will be a little different for the backer bearings. I will be ordering 4 or 5 band sawmill blades for doing tough or better quality cutting, their width is 1 1/4", but I would also like to use up the rusty stack of 1" blades I have in storage for cutting small stuff and other less quality work. The adjustable backer bearing will allow me to switch between different width blades.

Thursday, August 9, 2018

What Bearings To Use For Guides

So I didn't do much today, spent a good part of the afternoon trying to decide which bearings to use for the guides. I pulled out one of my bearing storage boxes, I usually decide better, when I can actually handle the parts. My other boxes are all housed bearings.

I went out to the storage shed and found the Delta parts storage box and brought in the old Delta guides. Wow I obviously didn't look at them when I dismantled the saw. The two aluminum guide blocks were almost cut in half, one bearing was seized and the other had a worn groove so deep it exposed the bearing balls.

Here is a close up of one of the destroyed bearings. The scrapped saw obviously came from an industrial plant. No owner would continue to run a saw in this condition. I wounder how many blades they destroyed to accomplish this kind of wear.

I did find two good bearings to fit the mounting studs. But the guides are an old design and too damaged to get much life out of them. The blocks will make good feed for the melting pot.

Digging through my bearing box, I found these four gems. They are too small for the sawmill, but quite heavy duty for there size and mounted on eccentric shafts, which makes it easy to mount and adjust. I think my 12" shop saw is getting new guides soon.

So in the end I decided on a heavy RBL 20 mm bearing. I have 10 new ones in stock, so I will have 4 left over for future replacements and I have lots of 20 mm shafting. I am going to try to get the mounts drilled eccentric to make them easy to adjust. I am looking at something close to what you see in the picture, the bearings are sitting on. The picture was printed from the "Vehicle Wheel Band Sawmill" file I uploaded in a previous post.

Wednesday, August 8, 2018

Completed Tension And Tilt Assembly

So put in a good day out there, accomplished what I set out to do. mainly rebuild the tension and tilt assembly to get the adjustments facing the operator and increase the adjustment clearances.

I started of with the tilt adjustment. I decided reversing the adjustment shaft and shortening it would be easy enough. First operation was to drill the end of the internal thread deeper, cut it off to the desired length and re-thread it.

In this picture re-threading the shaft after cutting off.

After threading I cut a piece of 1/16" steel to shape and bent it to fit over the tilt arm. I then drilled it to accept the 3/8" adjustment bolt, inserted the bolt and welded it. This prevents the bolt from turning when you adjust the tilt handle. The large washer on the handle side covers the inset that prevented the bolt from turning in the Delta design. I didn't want to weaken the tilt arm by milling an inset there. Here is the assembly complete.

Here is another view. 

So on to the tension assembly, This one will require a little more work. I started off by step drilling a 3/4" hole in the bottom of the Delta spring housing cast into the adjustment slide. I then sawed and filed the web casting and the top of the spring housing to accept a 1/4" steel disc, drilled to 13/16". The disc has a slot ground in the side to engage the casting .

This 3/4" nut will be welded to the disc, the slot in the steel disc will prevent the nut from turning when the adjustment screw is screwed in.

Here the nut is welded to the disc and trying out the screw. Great, works just the way I envisioned it. 

So here are all the parts to complete the tension assembly. The knobs are a little large, and I couldn't find two black ones.

Correction, had another look and found two smaller black knobs, had to re-thread them though. So here is the reworked tension and tilt mechanism all welded and assembled.

Here is a view from the back side and the new tilt adjustment. 

So when I reassembled I made some adjustments to alignment. I reinstalled the wheels and a blade, applied lots of tension and turned the wheels, a small adjustment to the tilt and the blade tracking centered on the wheel tires and stayed there.

A closer view.

And a larger view of the complete assembly so far.

So we are ready to start on the blade guides, maybe tomorrow.