acme rod plans for bandsaw mill

[revid]

I posted this in another forum before I saw this on but wondering if anyone made a saw mill and used acme threaded rods for their height adjustment? In the process of making up one and would like some info on sprocket size,chain size and how it worked for them.thanks

[47sawdust]

My first mill was a Kasco that had acme threads for height adjustment.It was very accurate but much too slow for my needs.

[KirkD]

Linn Lumber in Oregon uses them on their mills and have pics on their web site. I thought about it on my first mill but after seeing the chain and sprockets that Woodmizer and others use I feel it would be best cost wise and very efficient.

[larrydown60]

Hi reved, I am building a saw mill too Mine is going to have 2 -20 tooth sprockets on top of acme rod 11/4 x5. 1- 54 tooth gear on elect motor to lift the acme rod a18 tooth sprocket for for the idle tensioner and another 15 tooth sprocket on top of the 20 tooth acme sprocket connected to the the 54 tooth sprocket Another chain connects the 2- 20 tooth sprockets with a tensioner w/18 sprocket to take up slack between the 2 rods I hope it makes sense to you

[Remle]

Check the post below this or do a search for it if it is no longer their "Saw mill Kits" for they way member iffy added a wheel chair motor to his mill with acme rods.

[ladylake]

With acme threads you want to use bronze nuts which last a long time and don't wear the rods out.  Steve

[ozarkgem]

I think you would be happier with a hydraulic cyl and chain lift like on my Mitey Mite. I think other mills use that system also. Works excellent and a lot simpler and cheaper to build. That is if you have hydraulics. Some where there is pics of my set up on a post. I also think it would be a lot faster than the Acme screw.

[sandsawmill14]

timberking used the acme rods on the b20 and maybe others it works well but is a little slower than i would like

[Den-Den]

My home built mill uses acme rods for height control.  It is a slower system than some others but is simple and precise.  I would not recommend this set-up to be manually powered (tried that and it was NOT fun).  I am not sure that the precision of acme rods is worthwhile unless it is accompanied by some type of set-works.
The specs:
1" 6tpi acme rods  The ends are turned down to 3/4" and run in ball bearings.
22 tooth sprockets on the rods driven by a 33 tooth sprocket on a 30 - 1 gear reducer which is driven by a 3/4 hp 3 ph electric motor.
There is a notched wheel attached to the 33 tooth sprocket with a proximity sensor located to trigger when the notches pass by.  Each notch equals 1/32" vertical travel.
A variable frequency drive converts 120vac into 240v 3ph and powers the motor.
A small PLC keeps track of the pulses and controls the variable frequency drive to give me precise thickness control.
Downsides:
* 120vac power is required
* Speed; when cutting 4/4, I have enough time to engage the clutch and throttle up while the head is dropping.  When cutting thick material, have to wait a few seconds before pushing into the cut.  I have come up with a modification that would improve the speed but it is a hobby mill that is all manual except the vertical travel so making that change has not been important.  May do that when I add power feed.
* I keep the rods lubricated with a squirt bottle of diesel/ATF mix, necessary but a little messy.

The acme rods could also be powered by hydraulic motors or DC electric motors.

I will provide details on the controls if someone is interested.

[Ox]

On the mill I built I used heavy duty threaded rod, 3/4".  1 in 12 thread pitch(I think, it might be 1 in 16).  I used sprockets and chain to run it.  I used a large sprocket on my remote mounted hand crank with a chain running to a small sprocket on one of the threaded rods.  Another chain runs to the other threaded rod on the other side of the mill head.  I have it made so I have one turn for 1/4", 4 turns to the inch.  It's slow and precise and easy to count the turns for the inches.  If I'm figuring in kerf I add another half turn for this (1/8").  For a 2" board I'll crank down 8 1/2 turns to allow for kerf.  I keep all this stuff oiled well with Fluid Film.  I have some cheap wire brushes zip tied so they're always rubbing in the threads to keep sawdust off and out of the stacked nuts.  Time will tell if this was a good idea, using threaded rod instead of Acme rod.  So far so good, but I don't have thousands of hours on it either.

[Rougespear]

My mill uses acme rod... that being said I think there were better ways to do it now that I have done it.  (I tried cable wrapping on a drum but hated the inaccurary).  Without a doubt ACME is accurate, and I want that because I will integrate a rotary encoder and PLC for a setworks in the future, and I like that I get 1800 degrees of rotation for each inch.  If you can get a pic of the woodmizer or cooks setups with chain lifts, I think they are nice.  Also, the best setup would be how TK does it with cables attached to a hydraulic cylinder... but - use a cylinder with a tempersonic probe inside so that positional feedback can be easily derived.  This is the most expensive method though.

That being said, I made mine so that it is not slow - I was aiming to move about 100-120 inches per minute, or 20 secs to raise the head from bottom to top.  Here are the specs (off the top of my head): 1"-5 acme thread in tapered roller bearings at bottom and top; captured in a delrin nut attached to the saw head; 14-tooth sprockets on the acme thread, 28 tooth on the hydraulic motor; 2.5 CI displacement motor gives me about the speed I want.  Hyd is nice because its simple to slow down.  Hope this helps.

Brent

[revid]

thanks guys,alot of info there.I bought 3/4 acme rods and nuts the other day,would have bought 1" but double the price.trying to best match ease of turning with half decent speed of adjusting. Was thinking about sprockets and chains and then using the gears of a trailer jack so I can turn/adjust vertically rather than reach up and over to adjust horizontally,hope that makes sense. I figure if it can lift a trailer up it can raise my saw setup. If I don't use a hand crank was thinking of using a small 1500 lb winch motor of a quad,what do you think? Hey larrydown60,Den-Den and Rougespear, can you send me some pics of your setup?
My email:rev.id@hotmail.com

[Kbeitz]

Winch motors use high amps.
Wheelchair motors have a whole lot less draw...
Just something to think about.

[sandsawmill14]

 

  

 

the gearing on the hf atv winches is 125:1 and they pull very little amps unless they are really loaded hard. the one in the pic above is running the 10' green chain i built and runs on 1 deep cycle marine battery it will last 45-50 hours of sawing before it needs charging but it doesnt run all time we turn it off and on when lumber or cants are on it. i would guess i runs about 1/2 the hrs of the mill when we are sawing sorry i didnt have a better pic of the winch itself :-\

[GF]

My hydraulic sawmill I built had them to begin with, the problem I had was sawdust would get in them and eat the threads up (I did a lot of cutting) and replaced them about once a year.  I used 4 - 1" acme threaded rods.  I then modified the unit removing the threaded rods and used heavy roller chain to replace each of the four acme threaded rods.  The chain has been going strong now for 8 years without an issue.  If you use threaded rod I would look at finding something to cover them that is flexible (like a vacuum cleaner hose) to get most of the dust out. This was my experience with the threaded rods.  The threaded rods were also slow compared to the chains.  I was driving the threaded rods with a low RPM high torque Prince hydraulic motor, which now is powering the chains.

GF

[revid]

thanks guys...Sandsawmill4, the rod from the big sprocket is for height adjustment or traveling ? Can you remember the number of teeth on each sprocket?Size of chain? Yeah wish you had more pics ,looks like a nice job.

[Wudman]

I used 1" by 5 thread per inch Acme rod.  There is one rod on each side of the 4 post head that is suspended in pancake block bearings from the top.  The two sides are connected by 4 inch sprockets and a chain.  To the left of the picture is a steering wheel that was pirated off a junk lawnmower.  I use it for minor adjustments (1 inch or 2 inch boards).  To the right hand side, I welded a 3/4 inch nut to the top of the Acme rod.  I use a Milwaukee cordless drill to drive the rod.  The drill will sit in the top of the 2 1/2 inch box tubing, so it is always convenient.  I can run top to bottom of the carriage in short order.  The system is very simple and works well for me.

Wudman

[revid]

thanks Wudman, what size of chain did you use and can you remember teeth count on sprockets? Thanks

[scrout]

I used 1:5 1 inch acme rods for my Linn style design.  Chain was either a 50 or 60 pitch.
At 5 to 1 you will need 60 rpm to get 12 inches of lift a minute, which is slow.   120 rpm is better.
My lift motor is an 120 VAC 1750 rpm run thru a gearbox at about 20:1, so plenty of torque.
If you want to get by with a smaller motor or something 12 volt, you can always counter balance the weight of the sawhead
so it is not so heavy.  6 feet of 1" x5 tpi is $53 on surplus center.   I just used std nuts, keep them oiled, but I dont saw a ton.
My setup will tend to freewheel on the way down, doesnt stop immediately, some king of electronic brake would help.
If you are not going to automate, I like the Norwood HD36 system.  It has a hand crank at 1 inch per rev, but counterweighted
so it turns pretty easy.  Their whole operator setup for a manual mill is pretty slick.

[sandsawmill14]

thanks guys...Sandsawmill4, the rod from the big sprocket is for height adjustment or traveling ? Can you remember the number of teeth on each sprocket?Size of chain? Yeah wish you had more pics ,looks like a nice job.

i am not sure i understand  ??? are you asking about the ones in the pic of the green chain or the ones i mentioned on the mill ??? either way i dont remember off the top of my head but i will try to remember to count both sets of sprockets tomorrow

[redprospector]

That green chain's pretty slick.

[sandsawmill14]

thanks it saves a lot of time working with a helper paid for itself in the first week or so 8) but i dont know if it would help a lot if sawing by yourself though and when i build the next one i will make it 15-16 feet long instead of 10 so there will be room for 3 stacks of lumber instead of just 2

[Wudman]

thanks Wudman, what size of chain did you use and can you remember teeth count on sprockets? Thanks

I believe I used #40 chain.  I think the sprockets are 24 teeth.  I am direct driving the rod itself, so in my case the sprocket size makes no difference (as long as they are the same)  The variable speed Milwaukee drill will spin to 1750 RPM (I think).  It makes short work of raising or lowering the head.  The Acme rods are rock steady.  There is no creep or movement in the head during sawing.  Adjustment by hand with the steering wheel is simple and efficient for short movements.

Wudman     

[revid]

Does anyone have a link to where can you buy 3/4 brass acme nuts/block ? what is a delrin nut? Can that take the strain/weight of a sawmill head assembly? Either ay all I can find is for small acme rods,nothing for 3/4 x 6 tpi. Would like a acme threaded block like Linn Lumber sells on their site although theirs is 1". I ran my setup a few times with iron acme nuts but it seems to be tearing up the treads.

[Kbeitz]

There is some steel ones on E-bay.
Check out McMaster Carr they have them.

http://www.mcmaster.com/#acme-nuts/=1218asp