iDRY Vacuum Kilns

Sponsors:

Running hyd motor in fwd and rev.

Started by Jim1934, June 01, 2021, 08:54:09 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Jim1934

Hi- I want to convert the carriage feed on my old circle saw mill
to hydraulics. I need to run the motor in one direction to cut and the other
direction to gig. Will use lever operated 4 way valve.
My problem: I get conflicting info on whether the motor rotation can be changed by
merely changing the pressure line (via control valve) from one motor port to the other.
A call to a manufacturer indicated this can be done as the motors are bi directional and reversible.
However that company has a video that shows a BMPH  motor being disassembled and changed to use it in a
different rotation. Motor is a "Dynamic" BMPH series.

Can someone who is actually doing this help? Thanks, Jim

Update June 7-21. Have decided to put hyd. on hold and try a smaller dia. cable drum.
Eight in. dia vs original 18. Some question in my mind if 1/2 " wire rope will have enough friction with 5 turns.
Thanks. Jim

Southside

Calling our resident hydraulic specialist @mike_belben 
Franklin buncher and skidder
JD Processor
Woodmizer LT Super 70 and LT35 sawmill, KD250 kiln, BMS 250 sharpener and setter
Riehl Edger
Woodmaster 725 and 4000 planner and moulder
Enough cows to ensure there is no spare time.
White Oak Meadows

mike_belben

Im not really that good but i can try to help.  I have more questions than answers for now.  

1. Does your mill HAVE this hydraulic motor on it or are you adding it on?  

2. And what is gigging?  To me thats spearing frogs at night.


I downloaded a pdf on those motors and see its some sort of gearoller with a double splined wobble shaft and fancy stuff inside, i have no experience with them.


If it is a bi-rotational fixed displacement motor then i expect reversing the A and B work ports will reverse shaft rotation without any issue.

3. Do you already have the valve youre going to use?
Praise The Lord

Jim1934

Thought gig was returning the cart/carriage in order to be loaded. Sorry
No motor on the mill now. Will be adding one.
I do not have valve.
Think all are bidirectional or reversible- But not sure this can be done just by changing
which port is pressurized. Suspect its one direction until you disassemble and change internals.
that is the queation. 

mike_belben

No, just switch the flow direction, almost like a cylinder. In A then out B or in B then out A. 


 You want a 3 position spring centered valve to make the motor run clockwise, counterclockwise and park when you let off the handle.  Spring center will auto return to park if you let go.  And you dont want any detents in my opinion. 

  I dont know if a "motor spool" is a good idea or not.  The neutral position would freewheel and allow the carriage to drift and over run at the end of travel.  I suspect a better setup might be to use a cylinder spool with relief valves in the work ports to prevent banging when you get to the end and let the valve return to center or shift to return home.  


Let me know if i need to clarify any of that. 
Praise The Lord

Iwawoodwork

Mike is right on , you do the forward-reverse of your carriage drive motor  just by the one correct control valve. That is how my Mighty Mite mill forward and reverse works, only instead of a cable drum it has a sprocket and chain. 

tacks Y

Do you already have the motor? A gear motor would work this way.

moodnacreek

Quote from: mike_belben on June 01, 2021, 09:14:25 PM
Im not really that good but i can try to help.  I have more questions than answers for now.  

1. Does your mill HAVE this hydraulic motor on it or are you adding it on?  

2. And what is gigging?  To me thats spearing frogs at night.


I downloaded a pdf on those motors and see its some sort of gearoller with a double splined wobble shaft and fancy stuff inside, i have no experience with them.


If it is a bi-rotational fixed displacement motor then i expect reversing the A and B work ports will reverse shaft rotation without any issue.

3. Do you already have the valve youre going to use?

moodnacreek

I don't know if it's because your young or because your form Mass.   On a sawmill carriage going into the log is called crowding and backing up is called gigging or gigging back.  At some point in history sawyers allowed frog spearman to use their term :D.

mike_belben

Quote from: Jim1934 on June 01, 2021, 10:02:05 PM
Thought gig was returning the cart/carriage in order to be loaded. Sorry
It might be, i just didnt know.  Im not a sawyer.
Praise The Lord

mike_belben

Quote from: moodnacreek on June 02, 2021, 07:29:38 AM
I don't know if it's because your young or because your form Mass.   On a sawmill carriage going into the log is called crowding and backing up is called gigging or gigging back.  At some point in history sawyers allowed frog spearman to use their term :D.
10-4 doug. Thanks.
Praise The Lord

Machinebuilder

I think that motor is not bidirectional. When ordering there is a special order option for reverse direction.

to be sure call the tech support line and ask before purchasing one.

There are many other hydraulic motors that are bidirectional.

For the valve I think you want a 3 position spring return to center, A to B center valve. this would allow free wheeling in the center position.


I'm not an expert on hydraulic motors but do a lot of industrial hydraulic work.
Dave, Woodmizer LT15, Husqvarna 460 and Stihl 180, Bobcat 751, David Brown 770, New Holland TN60A

mike_belben

Yes, you NEED a bi-directional motor. 


Having never run a circle mill i dont know if its better to let the carriage over run or not.  
Praise The Lord

PoginyHill

Good point, Mike. I think you'd want ports A & B to be closed, not open, so that the carriage would stop when in the neutral position. Open center for working ports is great for a winch, maybe no so good for a saw carriage.
Kubota M7060 & B2401, Metavic log trailer, Cat E70B, Cat D5C, 750 Grizzly ATV, Wallenstein FX110, 84" Landpride rotary hog, Classic Edge 750, Stihl 170, 261, 462

sealark37

Call "The Surplus Center".  Tell them what you want to do, and they will help you with the motor and the valve.

Satamax

Daft question, isn't it possible to find a whole hydraulic carriage winch on craigslist or ebay ? Or dafter even, a tower crane's winch?
French CD4 sawmill. Latil TL 73. Self moving hydraulic crane. Iveco daily 4x4 lwb dead as of 06/2020. Replaced by a Brimont TL80 CSA.

Machinebuilder

ya'll may have a good point o the valve center, I know almost nothing about circle mills.

Dave, Woodmizer LT15, Husqvarna 460 and Stihl 180, Bobcat 751, David Brown 770, New Holland TN60A

moodnacreek

I wish I knew more about this subject. The hyd. motors I run are on conveyers and they reverse through motor spool valves. A sawmill carriage takes a serious jolt every time you gig back. You also use the feed for a brake constantly. The old belt or friction feeds are slipping all the time. On a commercial sawmill the hyd. feeds start out at 50 h.p. So a small hyd. feed must be heavy enough and be cushioned somehow or it will surely break.

Satamax

Does your sawmill carriage winches look like this in the us?

https://www.leboncoin.fr/equipements_industriels/1137281049.htm?ac=206978287

It would may be, be too expensive to import one from this side of the pond. But there should be some somewhere laying around in the US.

Leboncoin, is a kind of equivalent of craigslist.  (it means the good corner) It covers all of France. And most of other european states have a sequel of this website.
French CD4 sawmill. Latil TL 73. Self moving hydraulic crane. Iveco daily 4x4 lwb dead as of 06/2020. Replaced by a Brimont TL80 CSA.

mike_belben

I dont have a lot of hands on experience with cushion valves but i think thats whats needed here to dampen the shock of stopping the carriage and log inertia at the end of the pass without carnage.

  A cylinder spool center with adjustable cushion valve to burp off the high psi jolt back to tank but not allow drift or over run like a motor center.  

Praise The Lord

Hilltop366

I have read before (don't remember where) that any hyd motor that turns anything with inertia should use a open centre valve, a motor valve should be easier to adjust feed rate. Could add a park break somewhere in the shaft or drum if worried about the carriage creeping. 

Jim1934

Quote from: moodnacreek on June 02, 2021, 12:31:18 PM
I wish I knew more about this subject. The hyd. motors I run are on conveyers and they reverse through motor spool valves. A sawmill carriage takes a serious jolt every time you gig back. You also use the feed for a brake constantly. The old belt or friction feeds are slipping all the time. On a commercial sawmill the hyd. feeds start out at 50 h.p. So a small hyd. feed must be heavy enough and be cushioned somehow or it will surely break.
Good point. I will have a gear reduction of 32:1 between hyd. motor shaft and the cable drum shaft. Existing gears are heavy duty.
Four are 3 diametrical pitch and 3 inches wide. Diameters are 18,4 1/2, 16,4. I will add another reduction of 2 with chain and sprockets at the motor end. This reduction results in the motor seeing one tenth of one percent of the carriage inertia.
I'm guessing the motor will not be damaged. Thanks for the post. Jim



mike_belben

Praise The Lord

Southside

Quote from: moodnacreek on June 02, 2021, 07:29:38 AM
I don't know if it's because your young or because your form Mass.   On a sawmill carriage going into the log is called crowding and backing up is called gigging or gigging back.  At some point in history sawyers allowed frog spearman to use their term :D.
Gee and Haw..... ;D
Franklin buncher and skidder
JD Processor
Woodmizer LT Super 70 and LT35 sawmill, KD250 kiln, BMS 250 sharpener and setter
Riehl Edger
Woodmaster 725 and 4000 planner and moulder
Enough cows to ensure there is no spare time.
White Oak Meadows

mike_belben

I know what that one means.  But my kids still dont obey.

;D
Praise The Lord

Thank You Sponsors!