Reeving a double pulley for cheese press?

[qdog1955]

  Does anyone know how to reeve two double pulleys for a cheese press if the pulleys do not have a becket ------I have had trouble locating pulleys with becket---of a reasonable size and price, for a block and tackle. If you have a source---size 3/8 to 1/2 inch---let me know.

Thanks, Qdog

[H-K-J]

I am going to use these, (as soon as I get to their store) or you may be looking for something totally different.

[smolt1]

Have you tried West Marine? They have lots of small sail boat pulleys.

[qdog1955]

  I Have looked at all the common places, no doubles with becket---the marine, rescue and sporting places have them----but either to big or way to expensive.
   I did find these at   http://www.uscargocontrol.com/Rigging-Supplies-Hardware/Double-Swivel-Eye-Block-w-Loop-SS304/Double-Swivel-Eye-Block-w-Loop-T304-5-16-x-1-1-4 ----$32 to 45$ a piece depending on size----the best price I have found.
  If you go here  http://www.ehow.com/how_5098217_set-up-double-pulley-system.html   ----they show how we always reeved a double pulley-----I just don't see how you can do it with out a becket.

And thanks for the input,
Qdog 

[Boofer]

Pardon my ignorance...what's a "becket"?

I've used something similar to this in this.

-Boofer-

[Schnecken Slayer]

It looks like a way of joining ropes. Also known as a sheet bend.

http://en.wikipedia.org/wiki/Becket_bend

[qdog1955]

   If the pulley has a fastening point at the top and bottom-----the bottom hole is where you would fasten your becket knot more commonly known as a sheet bend. So your right on, Bill----the problem is locating the right pulley.

   Boofer---thanks for the pics---I am using a similar set up and it works----the problem is when I tie the load knot back up to the top it makes the whole block and tackle twist and rub.
   Maybe I'll try to weld a becket on one of those cheap Harbor freight pulleys and hope I don't ruin the pulley.
  The link above to---us cargo shows a type of becket on the double pulley.

[ArnaudForestier]

Pardon my ignorance...what's a "becket"?

I've used something similar to this in this.

-Boofer-

And what a design it is.  Thanks for that one, Boof.

[qdog1955]

  Boofer
 Do you press on axle shaft bearings with that press?   I made a S.S. press, but only has an 18" arm (3-1ma)---so I needed the extra boost of the doubles for some more of the Alpines I want to try---I just want it to be easier to set up, since I only use it occasionally
  Qdog.

[Boofer]

  Boofer
 Do you press on axle shaft bearings with that press?   I made a S.S. press, but only has an 18" arm (3-1ma)---so I needed the extra boost of the doubles for some more of the Alpines I want to try---I just want it to be easier to set up, since I only use it occasionally
  Qdog.

Yeah, it's a little overkill for a cheese press. At the time, it seemed like a great idea. I thought I needed something to press the hell out of the cheese. I discovered later that I perhaps could get away with something a little less hurky.

Bottom line...it gets the job done.

-Boofer-

[awakephd]

If you REALLY want to up the mechanical advantage ... here you go: http://www.amazon.com/Rope-Pulley-Block-Tackle-Hoist/dp/B001Z0WELC/ref=pd_sim_hi_2?ie=UTF8&refRID=0YA62GNPTY9YVRJWGJK0

(Note that this does not use a becket on the pulley.)

As for welding onto the inexpensive Harbor Freight (or Home Depot or similar) pulleys -- the housing of the pulleys looks like some sort of cast metal ... possibly pot metal? I'd want to do some careful testing before firing up the welding torch ...

[Schnecken Slayer]

   If the pulley has a fastening point at the top and bottom-----the bottom hole is where you would fasten your becket knot more commonly known as a sheet bend. So your right on, Bill----the problem is locating the right pulley.

Ah yes, many years sailing a 14 foot cat teaches you a little about ropes and pulleys.

[Andrew Marshallsay]

If you can't find pulleys with beckets, you can have the end of your line attached to a saddle, either on the frame or the lever of the press. This is how I did it.
The blocks made for dinghies or yachts might be your best bet. They aren't cheap (nothing to do with boats is) but they probably be much better quality than anything you can get from a hardware shop. They will also probably have roller bearings and be much more efficient. You would be surprised how much force will be lost through friction. A 3:1 tackle with roller bearings may well deliver greater force at the business end than a 4:1 tackle with plain bearings.
The big question is, how much purchase do you want? For big forces a cascading tackle is worth considering, as shown here: http://www.westmarine.com/WestAdvisor/The-Vang

[qdog1955]

  Thanks Andrew!!  A three to one like that, should work well for me. Sometimes I regret using all this stainless---it's so much easier to fasten and refasten things on wood.
  On the other hand---Darn you Andrew now I'll have to reconfigure all my weight and MA worksheets.

  Thanks,
Qdog

[awakephd]

A very good point about the friction in the garden-variety pulleys available from Home Depot and similar places. In my experience, though, these generally do not have plain bearings, at least not in the sense of having oilite or other bronze bearings; they generally have no bearings at all -- just a pin through the hole in the sheave, rubbing its merry way to a great deal of friction.

Of course, if the sheave is made of a low-friction material, such as acetal, it can serve as its own bearing to some degree. I don't know what the implications would be for how much weight it could handle ...