Band Saw pulley's, DIY and a couple of questions

[PuG]

Hi, first time post on these forum's - been reading a few topics and hoping to ask couple of more specific questions (which I know have been answered but im looking at a slightly large scale machine).

Currently designing a band saw, probably come to nothing but enjoy process of doing CAD.

Basically its a simple ladder bed, with a double upright supported head, powered pulley via hydraulic motor and a blade tensioner, going of to a tractor PTO pump via block of spool valves etc (which cover the log rollers, vertical chocks, and head horizontal movement along the bed and so on).

I've found the blades I wish to run which are Stellite tipped. Pulley wheel diameter of 610mm, cast steel, and unknown depth at the moment, possibly 90mm?

4" x 18'0" x 1.05mm x 1½" E/NCT Stellite tipped wood cutting bandsaw

http://www.gerrymet.co.uk/acatalog/Stellite_tipped_wood_cutting_bandsaw_blades_example_2.html

Does the 4" represent overall blade width? or 4" plus 1.5" of teeth?  so 5 1/2" in total?   
Depending on the answer presumable looking briefly at Serra 130i the pulley would need to be either 90mm of flat running surface or 102mm.

The pulley will be flat, trimmed by shims on the pillow bearing blocks to run true, however I presume it will need a rear lip to prevent the blade sliding of the back face of the pulley wheel when cutting?

Head vertical alignment. My current idea was to use a liner screw either side connected together via a sprocket and chain at the top powered either directly by stepper motor or a servo controlled hydraulic motor (with a rotary encoder) linked back to an Arduino/Raspberry PI with controlling software to allow accurate head placement and semi automation. However! my only concern is speed of the head will operate in moving up and down. Which probably wouldn't matter. Though any other recommendations? or methods of doing it correctly. I know some use Setwork's but it difficult to find useful information.

Thanks, James

[justallan1]

PuG, welcome to the Forestry Forum.
With the experience here, there should be someone along soon to help you out.
Do you have pics of your draw-up? We love pics.

[beenthere]

Welcome to the Forestry Forum.

Ambitious plan you have there. Somewhat following your thoughts, but sounds like you may need to gain some experience with wide band saws and what keeps them aligned on the wheels. I've never seen a "rear lip" to hold a band on the wheel. Maybe you have. ;)

What are your production plans?
Keep us posted.
And pls add your location to your profile (helps to have an idea where you are at when reading your posts).

[PuG]

Thanks, added a picture.

I've never seen a "rear lip" to hold a band on the wheel. Maybe you have. ;)

To be honest neither have I, as I'd been working under the theory with the offset in the teeth and the fact it should be cutting and not forced through the wood should be sufficient. Never any harm in asking!

This is only a preliminary re-design of one scrawled on paper over last few months!  6.5 meters long, maximum cutting width just under 1.16mm (45") with a 18ft blade.

Bed consists of 1400 x 250 x 20mm plate steel laser cut and welded to the universal beams (there will be cross supports and some plates won't have weight saving holes cut for extra rigidity and bolt ability).

Log roller and vertical uprights will be bolted accordingly to the central plates. There not included at the moment on the picture.

Lifting arms are 25mm thick steel (going to modify the shape to strengthen) and twin 285mm stroke rams, based on the Wood-Mizer so it will fold up and over the bed for transport.

The actual cutting head will run on 8 steel rollers (four below), inner wedge plates welded to the vertical pillars and the outer bolted to allow easy access to change bearings etc.

The head at the moment im still working out. However expanding 100 x 100 x 10mm box steel for outer sheath and 90 x 90 x 10 inner with a ram situated just below (possibly moved internally for extra clearance) which eventually is attached to a pressure relief valve on the control station to hopefully maintain a constant and to allow bedding in new blades easier. Plus shorter cheaper ones for bulk smaller tree's.

Roller guides shouldn't be needed but allowed for and will have at least nylon cleaning blocks. Lube will be applied directly to the pulley wheels and not forgetting a currently missing debarker! run of the mill standard design.

Twin axle rated to 1200kg will be bolted on and suitable approved coupling (both are pre manufactured). Total target weight is 2 tons, currently weighs in 1461.6 kg's (that's with allowance for all hydraulic rams and motors but not for extra steel of missing bits) so will beef up if spare to play with.

No need to haul and engine around that I have covered with PTO pump. Going for simplicity and ease of maintenance and I reckon average tree diameter will be working is about 22" so plenty of scope. Possibly narrow the design down if weight starts to become a problem.

Before anyone mentions there will be safety cowling! and sub 10 second braking system on the pulleys with ideally a electrically emergency stop located in several locations.

Over in the UK.

My production idea is if I can get to a stage that im happy with a design then the firm supplying steel will cut and weld the bed and lifting frame in one go so its true. Then once arrived will work on the rest myself and use the local engineering chap up the road. Pulley wheels probably from a Sheffield foundry.

Biggest concern is if it doesn't work, i'm weighing up versus a cost of a second hand LT40 super hydraulic.

- James

[beenthere]

Try again on the picture... needs to be in your gallery (good on the pic).
And location in your profile... as I'm sure that if you have been reading many posts on this forum that you appreciate knowing the location of the poster as you read.

[york]

PuG,

Your build looks interesting and i will follow it....I have a metal cutting band saw that has the lip on the band wheels....Good luck.....

[Herb Brooks]

https://forestryforum.com/board/index.php/topic,68127.0.html
For your set works consideration.

[PuG]

https://forestryforum.com/board/index.php/topic,68127.0.html
For your set works consideration.

Thanks, will take a read later today. Just came across a youtube video with a chap who's used the same system, stepper motor and a Arduino. The coding side is fairly straight forward.

https://www.youtube.com/watch?v=Fc5CRJCRSE8