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On a bandsaw carriage with 4 wheels...

Started by SineWave, November 02, 2016, 06:24:08 PM

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SineWave

For those of you who have bandsaw mills with 4 wheels on the saw carriage, do you find that you have any trouble with the carriage "rocking" due to the weight of the log on the mill causing the rails to strain such that they're no longer perfectly parallel?

If so, how do you address this? Do you put some kind of spring suspension between the wheels and the carriage to soak up any differences?

Or do you just block up the bandsaw mill with lots of supports/cribbing so that it doesn't strain enough to worry about?

Or do you allow each pair of legs and wheels on the carriage to move independently, so that all four wheels will always be on the rails?

Or maybe (now that I think about it) are you super careful when you weld/bolt the bunks to the rails so that they are perfectly parallel, and therefore the "contact patches" on the rails for all four wheels will always be co-planar?

Sorry if this is a dumb question, and thanks in advance for any replies.

Kbeitz

I put 6 wheels on my carriage. 4 back wheels have slots for adjustment.
This way I can keep the blade parallel to the track.
You need to fix your track so it does not flex.
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

SineWave

Thanks, Kbeitz. Don't have anything built yet, just trying to anticipate possible stumbling points.

ozarkgem

Select uses v-groove on one side and flat wheels on the other side. Course they have a very heavy carriage. I think circle mills use this system also. I have some 10 inch railroad style wheels I am going to use.
Mighty Mite Band Mill, Case Backhoe, 763 Bobcat, Ford 3400 w/FEL , 1962 Ford 4000, Int dump truck, Clark forklift, lots of trailers. Stihl 046 Magnum, 029 Stihl. complete machine shop to keep everything going.

Kbeitz

If I see one wheel that's not turning I know I need to re-level my mill.
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

Joe Hillmann

On my mill the carriage probably flexes enough that it isn't an issue but when I originally built the mill I made slots for adjustments for each wheel.  I haven't adjusted them since I built it.

sandsawmill14

build the frame heavy and block it enough that there is NO flex ;) :)
hudson 228, lucky knuckleboom,stihl 038 064 441 magnum

thecfarm

My Thomas has 4 wheels and never had a problem. But I also think I could pick my mill up by one corner,shake it and put it back down and it would still cut true.
Model 6020-20hp Manual Thomas bandsaw,TC40A 4wd 40 hp New Holland tractor, 450 Norse Winch, Heatmor 400 OWB,YCC 1978-79

Bill Gaiche

I had this log on my home built mill a couple of weeks ago. Largest as of today and hopefully the last. The mill sawed it just fine and there was no flex in the frame. The guys calculated that it weighed 6,000 lbs before we cut about 1/3 of a slab from it. It was 12' 6" x 40" at the butt and 32" at the little end.



  

 

dgdrls

Build a stout frame and then add a little more to it.
The Carriage on most bands is there to carry the saw not the log.
Good base make alignments easy,

D

SineWave

Thanks for the replies, everyone. I appreciate the info.

kelLOGg

My Cooks mill 4 carriage wheels always make contact with the rails. There is some lateral play in the wheels to allow for rail sections that may not be straight but wheels never lift off the track. The rails are just spot welded to allow for replacement in the event of damage to them.
Bob
Cook's MP-32, 20HP, 20' (modified w/ power feed, up/down, loader/turner)
DH kiln, CatClaw setter and sharpener, tandem trailer, log arch, tractor, thumb tacks

DMcCoy

My base is 6 x18 PT bridge timbers.  I put my tracks, 1 guide 1 flat, on a 2x6 on top of those beams.  This allows shimming if needed to level the tracks and fortunately I did not have to shim.  My bunks are independently adjustable for level.  Those beams are so heavy I only support the ends.

I made no adjustment for my carriage wheels.  So I spent considerable time making sure and adjusting the frame to be flat and true.  Pics in my gallery if you are interested.  The track wipers I consider to be essential.

Kbeitz

Quote from: DMcCoy on November 03, 2016, 09:23:09 AM
My base is 6 x18 PT bridge timbers.  I put my tracks, 1 guide 1 flat, on a 2x6 on top of those beams.  This allows shimming if needed to level the tracks and fortunately I did not have to shim.  My bunks are independently adjustable for level.  Those beams are so heavy I only support the ends.

I made no adjustment for my carriage wheels.  So I spent considerable time making sure and adjusting the frame to be flat and true.  Pics in my gallery if you are interested.  The track wipers I consider to be essential.

Wipers is something I need to add. About every other log I'm cleaning my tracks.
What did you use for a wiper?
Collector and builder of many things.
Love machine shop work
and Wood work shop work
And now a saw mill work

DMcCoy

I used black walnut.  I read somewhere that it is rot resistant, ok for use as sill plates in house construction.  You want them to have a gap - not tight to the wheel.  Cleans both the wheel and the track.  Here are some pictures;


 

You can see the hole where I had bolted on flat belt wipers.  These were troublesome to say the least.  The block type are self adjusting for wear-  Kudo's to Jeff for the idea.


 

kelLOGg

My rails are 1" angle iron oriented like an "L" for easy wiping by a small piece of free floating plywood w/ a notch.



 
Cook's MP-32, 20HP, 20' (modified w/ power feed, up/down, loader/turner)
DH kiln, CatClaw setter and sharpener, tandem trailer, log arch, tractor, thumb tacks

SineWave

Great information, everyone, thank you.

Funny you bring up the topic of rail wipers, because this was one of the first things I wondered about bandsaw mills!  :D

DMcCoy, do you have any detailed pics in your gallery of those self-adjusting wipers? I looked but didn't see them. Or maybe I'm overthinking it, and they're just grooved blocks of wood held in place to ride, and wear, by gravity...

DMcCoy

They are ingeniously simple, again kudo's to Jeff (Site Admin.), he has a sketch posted on here somewhere.  They sit by gravity on the track, rub both the wheel and the track.  They are not attached to the saw frame in any way.  They just slide along the track pushed by the wheel.  Make sure they are above 1/2 of the wheel height on the wheel side.
I like KelLOG's design too, his should be wear adjusting as well.  Depends on what you are planning on using for track.

Like Kbietz - I had to wipe my tracks too much until I built the wipers.  I think they are very worth the time to build them.

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