Thread: Homemade Bandmill (update)

Hey Dean! What PSI are you pumping the Porta Power too? I am thinking of going Hydraulic tension on My Mill, Currently I just have a screw thread and it is hard to get accurate tension on the blade.

Cheers,
Jon

Hi Jon,
I used a ram off a disused Lely hay mower, I cut & welded it to reduce it stroke to a only a few inches & mounted a spring behind it to work as an accumulator . It has a 50mm bore diameter. I'm putting about 1000PSI into it generating about 3200 pounds of force. Could go higher if needed but not required as its cutting straight.

The band needs about 1600 to 1800 pounds of tension, x 2 = 3200 to 3600 pounds.

The oil pressure you will need to opperate a ram at a given force will be dependant upon the rams bore diameter. for example if I had a 38mm bore I would need to increase oil pressure to about 1800PSI to get the same force

Regards,
Dean.

Thanks for the info Dean, It is so hard to get good info on building a Mill,I live next door to a bloke who owns a Bearing and Hydraulic Business, He is a good bloke to Know, We have been looking at using a Jack Ram out of a trolley Jack but we can't get access to the oil journals to attach a Gauge. I built mine a couple of years ago, and I am looking at Refining it a bit. I originally started out building a Portable mill that I could transport but I made it that Heavy that it has to remain in Situ as I don't have many Mech aids at my disposal.
Good luck with your ongoing Project.

cheers, Jon

Dean

Missed this thread earlier, but love the build. Very well done.

Regards
Paul

Originally Posted by newjon

Hey Dean! What PSI are you pumping the Porta Power too? I am thinking of going Hydraulic tension on My Mill, Currently I just have a screw thread and it is hard to get accurate tension on the blade.

Cheers,
Jon

Jon

I realise you may have gone down the hydraulic track, but if you haven't or as an intermediate measure, try using a torque wrench for tensioning. This will give you a consistent reading. My Laidlaw was supplied with a simple bar indicator but has long since given up the ghost and for a long time I have relied of "feel," I would suggest you delve into your automotive tool kit and drag out one that clicks when you reach the right tension.

To preempt the obvious question, I don't know what the right torque is, but I can tell you that if you break the band, it was too much.

Regards
Paul

Well its 6 months on & I've finaly got the mill out of the shed & can now have a clean up. The sub frame / drawbar is now fitted along with axle & cast wheels from an old Crump spreader.
I was asked whether I could mill a few logs for a local community project, so I jumped at the chance as it enabled me to see how it would work in a portable situation.
So last weekend I hooked it up to the tractor & drove about 10kms up the road to the logs. Mostly it all went very well, some very nice macrocarpa was sawn, only had a couple of littly "oopsies" such as leaving a steel backstop a few mm too high & "zzzzing" hitting it with the blade, and milling a small log without a clamp as I already had another log clamped on the deck, not a good idea.

I learnt a lot from this exercise and need to make more mods & changes, particulary log rotation and handling, things like toe board for adjusting for log taper, rollers for easy handling of slabs for resawing.

pics below

cheers,
Dean.

Dean,
thanks for the update on your mill. I have been pouring over your photos and am NOW encouraged even more to have a go at making one of these mills myself. I have also spent last few months pouring over all the youtube videos from the brand-name machines all the way through to the DIY ones. There seems to be a general pattern appearing in my mind as to how best tackle the construction of the key elements - I must admit I am still trying to lock down the specific ways I will deal with certain details...ie....I will likely use square threaded acme rods to lift the cutting platform on the main frame. (I will likely attached a winch motor via sprockets and chains to drive the threaded rods. I was also looking at the option of mounting bearings/runners to the vertical sleeves of the motor platform (the sleeves that contain the SHS verticals of the main frame)...to reduce the amount of friction and "stick" on the up-pull of the winch cable....anyway - the most challenging component that I am still deciding on...are details relates to the platforms that will hold the main wheel axles...in essence I am trying to figure out the best combination of elements to allow me to (1) tension the blade and (2) toe-in/out and up/down the wheel axle. Is there anything you could suggest (from your own experiences) that would shortcut my dilemma regarding this detail.
I don't have anything built as yet....I have just started to buy all the steelwork, bearings, axles, wheels etc....motor etc.....construction and a thread following the progress may evolve soonish...

look forward to your thoughts....I may try and draw a few options (of the detail i'm thinking about) and see what you think of it....
regards
szczepan