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
I am going to use these (http://www.harborfreight.com/2-inch-double-wheel-rope-pulley-2-piece-set-92309.html), (as soon as I get to their store) or you may be looking for something totally different.
Have you tried West Marine? They have lots of small sail boat pulleys.
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 (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 (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
Pardon my ignorance...what's a "becket"?
I've used something similar to this (http://www.amazon.com/IIT-35005-Double-Pulley-2-Inch/dp/B00821MQ6U/ref=sr_1_3?ie=UTF8&qid=1412547036&sr=8-3&keywords=double+pulleys) in this. (https://cheeseforum.org/forum/index.php/topic,4026.msg36886.html#msg36886)
-Boofer-
It looks like a way of joining ropes. Also known as a sheet bend.
http://en.wikipedia.org/wiki/Becket_bend (http://en.wikipedia.org/wiki/Becket_bend)
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.
Quote from: Boofer on October 05, 2014, 10:29:44 PM
Pardon my ignorance...what's a "becket"?
I've used something similar to this (http://www.amazon.com/IIT-35005-Double-Pulley-2-Inch/dp/B00821MQ6U/ref=sr_1_3?ie=UTF8&qid=1412547036&sr=8-3&keywords=double+pulleys) in this. (https://cheeseforum.org/forum/index.php/topic,4026.msg36886.html#msg36886)
-Boofer-
And what a design it is. Thanks for that one, Boof.
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.
Quote from: qdog1955 on October 06, 2014, 11:25:55 AM
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-
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 (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 ... :)
Quote from: qdog1955 on October 06, 2014, 10:56:15 AM
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.
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 (http://www.westmarine.com/WestAdvisor/The-Vang)
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
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 ...
The tackle shown in the photo is actually 4:1. There are four sections of line falling from the lever with the same tension on each, hence 4:1. Again, that is the theoretical ratio, not taking losses due to friction into account.
As for fixing, rather than welding you could consider self-tacking screws or pop-rivets.
It would seem like this discourse is wending its way along a similar path I set for myself when building my press.
Most cheeses don't require much pressing power. Most, IMHO, would encounter under 5 psi. Just sayin'.... ::)
-Boofer-
I agree. I just presss with stacking weights and press all my cheeses with 2.5 PSI or less and I get good rinds even on my cheddar types. Pressing in the pot to keep the curds warm is easier, and more effective, than upping the pressure in my view. A decent press that lets you get to 5 or 6 PSI will get you pretty far.
Correct me if I'm wrong---I'm looking for 5 PSI on an 8 in. mold---I would need approximately 250 lbs.----my press only has a 3 to 1 mechanical advantage-----that would require about 80 lbs. of weight------that would be 10 one gallon bottles----I think I'd rather use the pulleys and hang a couple bottles.
Having said that, I think you are all correct, I seem to have had better results with less psi, especially with my smaller molds. But I would like to try some Alpine type cheeses and my understanding is I will need more Psi with those types. Am I mistaken on that?
Qdog
A very informative thread indeed :). On my latest press design I decided to "build in" the tackle (kind of like you did RawPrawn on your bottom pulley). My earlier version of this had a double upright and a single arm but by going to a double arm it allowed "space" to put in a dual pulley and it also gave a better pivot for the pressing arm. I put the "press" pivot point halfway between the upright pivot and the end. I did a quick check with a weighing scale and it seems to be about a 6:1 advantage including friction, but I probably need to re-check. Pulleys were made of HDPE spacers along with a large dia. SS washer and a couple of HDPE washers.
Quote from: qdog1955 on October 10, 2014, 07:50:47 PM
--I'm looking for 5 PSI on an 8 in. mold---I would need approximately 250 lbs.----my press only has a 3 to 1 mechanical advantage-----that would require about 80 lbs. of weight--
Qdog
Those numbers look about right. Can I assume that the 3:1 mechanical advantage is from the lever alone, without a tackle? If so, a 4:1 tackle will give you a 12:1 MA overall and you would only need about 21 lbs to give you the 5 PSI.
When you do set it up, you might like to check the actual force with bathroom scales or something similar.
Wow, Andrew, I messed that one up. The 3 to 1 is just the arm and I was thinking that the added double (4-1) would give me a 7-1---so your saying it would actually be 12-1 ? I'm assuming, 3 times the four?
This is why I'm not a Physicist.
I did check the 3-1 on a scale---and that was right on.
Thanks for the help.
Qdog
Quote from: qdog1955 on October 12, 2014, 11:02:30 AM
--so your saying it would actually be 12-1 ? I'm assuming, 3 times the four?
Exactly right. Happy pressing! :)