Manual clutch

[charles mann]

At about 1:50, a bell housing can be seen on the back of the detroit power plant. 


On another vid of their's, i saw him move a lever, loading the engine a little, then going to high idle for operations. 
I FB msgd the person and he said he thinks its a rockwell, would send me a pic of the data tag, but he has a business to run and it probably slipped his mind, which, again, he has a sawmill business to run, not a parts/engineering business. 

Can someone ID/confirm the type, maybe even model? I need to get back on my big mill build and 1 of the things is the drive belt system. I think instead of more failed attempts at bell cranks/levers and linkage, maybe its best to find a manual clutch similar, or exact to the unit mated to the detroit. 
My google search hasn't turned up anything that even comes close to the looks of the bell housing/clutch when searching rockwell, but a result does pop up for a rockford, but that is only clutch packs/disks and pressure plate, no bell housing or anything that would mate to the engine bell housing. 

If i could find the type of clutch and bell housing, it might help determine what size shaft i need, if i have to change from the shaft i already have. 

[DanielW]

It's a 'Rockford' PTO clutch, not a Rockwell. Not sure of the exact model, but it'll be one with the SAE bellhousing to match the Detroit. The Rockford were the most common type of industrial power unit clutches, but still sometimes hard to come by used as they're in demand. I have one on the Detroit of one of my mills. Some heavy equipment like skidder, graders, and combines used them. Definitely would be the easiest way to clutch your Detroit. That guy should have more belts on those sheaves: Even with those large diameters, three 5V belts will only transfer about 30 or 40 HP at those RPM's.

You see those clutches (and engines with those clutches) on Sawmill Exchange, Facebook Marketplace, Kijiji, etc., but they often get snapped up pretty quick. You can still buy them new, though I suspect they'd be pretty pricey. 

[charles mann]

@DanielW 
thanks for the info. Iv got a cummins 4bt, but looking around online now that i know what it is, and even another FF post regarding the pto clutch, yep, for the price of a new pto, i might as well go with an ogura electric clutch rated for 100hp. A few yrs ago, just before the plandemic, the ogura was $1900, and looking at the rockford, new, $1700 ish depending size and whatnots and in stock availability, i might go electric and be done. 

[booman]

I am curious as to what electric hoist you are using.  

[charles mann]

I am curious as to what electric hoist you are using.  

i think you mean the hoist they use in the vid, correct? i would imagine its a 120v ac electric hoist, and it looks very similar to the hoist control we use to take our internal tank out and bring it in the acft. i think we got ours at HF. 

[booman]

Yes, thanks.

[charles mann]

Yes, thanks.

Then to find out the winch style, you’d have to comment on their videos and they should reply. But honestly, a google search for 120v ac winches, if you arent keen to buying HF stuff, should yield decent results. 
I know grainger sells them, but at a ridiculous price. May try msc direct as well. But im on yr 4 with my newest 12k badlands hf winch and its constantly exposed to elements and only reason i bought this second one, was operator error/tiredness and decided to run it in reverse and burned out the holding clutch. 

[mudfarmer]

I think these are also called an "over center clutch" if that helps with searching? Possibly also used on big honking wood chippers. Some of those maybe ran 4bt as well.

[moodnacreek]

On those clutches you first need to know the size, the s.a.e. number tells the basic size. The engine must have a sae flywheel and a sae bolt pattern [that will be a full circle].  All industrial engines should have sae bolt patterns and some others need an adapter. Big truck engines will have it but the flywheel will not be sae.

[charles mann]

Both flywheel amd eng bell housing are sae. I measured it early early this yr to mate a 60Hz gen head on it, instead of the 400Hz that was attached to it. 

[charles mann]

I am curious as to what electric hoist you are using.  

here ya go, they posted a vid of the log turning winch.

[booman]

Thank you very much for the info on the winch.   Looks very useful.

[DanielW]

If you go with an electric clutch, are you considering putting sheaves right on the crank output of the 4BT? I've seen a few circular mills where people have belted right to the crank of an old engine. It works, and for a few hours a week you'd probably be fine, but when people to that they're putting a pile of side-load into the rear main bearing, which wasn't really designed to take any. Better to couple it through some u-joints to a jackshaft with its own separate bearings.

[charles mann]

If you go with an electric clutch, are you considering putting sheaves right on the crank output of the 4BT? I've seen a few circular mills where people have belted right to the crank of an old engine. It works, and for a few hours a week you'd probably be fine, but when people to that they're putting a pile of side-load into the rear main bearing, which wasn't really designed to take any. Better to couple it through some u-joints to a jackshaft with its own separate bearings.

Iv got a pillar block bearing between the flywheel and belt sheave mounted at a 45° angle to limit side and downward load. 

[handhewn]

I have an over center manual clutch on my 60" circular with GM671 diesel. Its been working perfectly for 40 plus years that I know of. No problems ever. I could look for names/numbers on mine if you want. Also, There is a large over center clutch in my parts pile. When I say "large" , I say that because if I remember correctly, the output shaft is 3 to 4 inches dia. and that seems to me to be "large". Anyway, it is very heavy duty. If you have questions in this regards, contact me.

[handhewn]

I just went and looked and this clutch is a twin disc and the output shaft dia. is 3.5 in.

[Joe Hillmann]

If you are looking for a cheap clutch, you can build a simple one out of a rear differential from a truck.

Depending on how you configure it it would give you about  a 1:1.5 increase or reduction in speed.

From the engine you would connect a drive shaft to the front U joint on the differential.  Then one side of the diff is connected to the saw, the other side has the brakes left intact.  To engage the clutch you lock up the brake.  To disengage it you release the brake.  That would give you 1/2 of the gear ratio decrease from engine speed.

Or if you want a 1/2 of the diffs gear ratio increase you would put engine power in from where one of the wheels was and take power out at the U joint.

It is also possible to get a 1:1 ratio but it requires putting power in at one wheel, taking it out at the other and putting a brake at the U joint.  However the diff was probably never designed to  spin that fast and would likely self destruct quickly.

Maintenance on the clutch is a simple as replacing the brake shoes/pads and drum/rotor when needed which should be very easy to get at.

Such clutches used to be very common before cheap hydraulics. If you want to see one in action search for homemade cable drilling rigs on you tube.

[charles mann]

If you are looking for a cheap clutch, you can build a simple one out of a rear differential from a truck.

Depending on how you configure it it would give you about  a 1:1.5 increase or reduction in speed.

From the engine you would connect a drive shaft to the front U joint on the differential.  Then one side of the diff is connected to the saw, the other side has the brakes left intact.  To engage the clutch you lock up the brake.  To disengage it you release the brake.  That would give you 1/2 of the gear ratio decrease from engine speed.

Or if you want a 1/2 of the diffs gear ratio increase you would put engine power in from where one of the wheels was and take power out at the U joint.

It is also possible to get a 1:1 ratio but it requires putting power in at one wheel, taking it out at the other and putting a brake at the U joint.  However the diff was probably never designed to  spin that fast and would likely self destruct quickly.

Maintenance on the clutch is a simple as replacing the brake shoes/pads and drum/rotor when needed which should be very easy to get at.

Such clutches used to be very common before cheap hydraulics. If you want to see one in action search for homemade cable drilling rigs on you tube.

For my application, i have ZERO room for adding a prop/drive shaft and a vehicle dif, nor do I need an reduction or increase in blade rpm. My setup is figured for 2000 rpm, which is controlled by an idle solenoid, and i have another 400 rpms before the ip governor is maxed, unless i went with a 5000 rpm governor (no need for the many rpms though), and i can adjust the rod end to reduce the rpms as well. 
I do not see how using a dif would act as a clutch. most common difs are limited slip, then an air or electric locker can be added for a "live" axle. The factory full time difs are becoming harder to find, but not impossible, and of course, there is always custom difs. Enough of my homemade mill is custom, i don't need anymore added one of custom stuff that if failed, good luck in finding readily available parts at the parts store. 
The dif option might work for someone else the has the room and needs the inc/dec in rpm, but I don't. i will also not be redesigning my eng mounting to accommodate such contraptions. I would barely have enough room for a pto clutch, but if im gonna spend the $$$ for a pto, i might as well pay for an ogura electric clutch, which i stated previously the same.
So, i think for now, back to the drawing board or sacrifice portability for ease of use and now that i have i genny that puts out 56k 3 phase, swapping to all electric and not having to worry about belt engagement. I can always source a boom truck, load the 6000# genny on the deck, couple to the mill and still be portable. but that is a further out project that is far on the back burner, pluto gets more heat from the sun than worrying about being a portable wide cut mill.