WHAT MAKES IT WORK? #7 The Differential Hoist - tubalcain mrpete222

[@countrycraftsman5110]

Thank you so much. I so enjoy your knowledge and the way you present your subject. I love the midwest as they call it a lot of great equipment came out of your area. God Bless you and yours.

[@mrpete222]

Thanks

[@alanhiggins299]

Brilliant! Thank you, mrpete22, tubalcain. I now know how I am going to make my "Warre Hive Lift". Just need to figure out the sling to pick up varying amounts of the stack.

[@mrpete222]

Thank you for watching

[@toddanonymous5295]

Mr Pete, Some people are natural teachers. That is you. You make learning both interesting and fun. That's why it is exciting when I see you have posted another of your great videos. My chain hoist is enclosed. Now I know what is going on inside. Thanks again.

[@mrpete222]

+Todd Anonymous THANKS very much--comments like yours are VERY encouraging

[@rfdave3980]

Mr. Pete your channel is so awesome. I enjoy it so much. Your the best shop teacher going. Thank you !

[@mrpete222]

Thank you very much

[@lonniedicus5111]

really helpful. just bought a used dif. block at swap meet. got it home and it did not work. after watching your video figured out block was rusted to shaft so it would not turn. after cleaning and some grease now works perfect. thank you for making video, it was great!

[@mrpete222]

👍👍

[@dexterkardas6559]

Hey there brother. I work in the entertainment industry as a certified rigger we use this same type of mechanical system but electric to move some serious weight. Just got to look through a old barn and found two of the old manual ones made by ford. Thank you for showing this stuff you produce wonderful easy to follow videos. I have been watching your series on the south bend lathe clean up and rebuild .it feels like you are right there with me redoing my old lathe.

[@mrpete222]

Thanks

[@EVILDR235]

As always I enjoyed your videos. I too have a 1/2 ton chain hoist that I bought in 1970. Mine is a Yale & Towne. I perfer it over a cherry picker. I have seen several people tip over cherry pickers with damaging results. I give the axles a little shot of oil before using it. Very simple machine that will out live me.

[@mrpete222]

+Chuck Small Thanks for watching

[@nitramretep]

As an engineer I appreciate your talent in explaining the mechanics of hoists and teaching ability. Excellent video(s)!!!

[@mrpete222]

+Peter M Thank you very much

[@edwardcook9957]

I would liked to have you as a teacher.You make learning fun.I always wandered how that chain full worked. Thanks for sharing. Keep up the good work we are never too old to learn that is what keeps me going. Ed

[@mrpete222]

+Edward Cook Thanks for watching & a nice comment

[@audreygreen-hite2075]

That was great easy for even a bone head like me allways wanted to see how the differential works. Thankyou. Luca

[@rossmindt]

I have now watched 7 of your 13 part series "WHAT MAKES IT WORK?" and I find them fascinating. Thank you mrpete! What a GREAT shop teacher you (are) would have been...... By the way, my viewing of the 1st 7 videos have been back to back viewing.....

[@mrpete222]

+Herb Mindt Thanks for watching Herb. Many more to come.

[@stephenwagar2663]

dear Mr.Pete ,dont listen to the complaners...all your videos are GREAT !!!!!!!

[@johnq.public5911]

I have one. I thought we were the only people that has one. Appreciate the time you take in your videos.

[@mrpete222]

Thanks

[@stilyou]

I just picked up the JUN/JUL’22 issue of Machinist’s Workshop magazine which has a feature article on a differential chain hoist that credits you for the inspiration! Way to go Mr Pete! You’re just like the ZZ Top song “I’m Bad, I’m Nationwide!” (And yes, I remember your distain for the modern vernacular of ‘bad’ meaning ‘awesome’ but I couldn’t resist!) 🤣👍🏻

[@mrpete222]

Thank you for telling me about that article, I was unaware. Very interesting

[@ramosel]

Mr. Pete, your Chinese Windlass video (excellent) sparked a memory of a course I had to take in Maritime Engineering many years ago. I still have the book so I looked it up. Today, an old friend who now watches your channel called because he wanted me to explain today's video to him... I told him you did a fine job but he just didn't get it. So for the engineering types... the core of this type of hoist is the torque split or difference (hence differential) between the radii of the major(R) and minor(r) pulleys being locked together. So your formula for the mechanical advantage is M = 2R/(R-r). The smaller the difference in size of the two bonded pulleys, the higher the mechanical advantage. So your forces involved are F(pull) = F(lift)/M. Thanks for the memories

[@mrpete222]

+ramosel Thank you

[@harveysmith100]

+ramosel Tell your friend to go to about 7:12 on the video. the 2 sprocket are fixed together as MrPete says. Now follow the chain down from the left side of the small sprocket, down to the weight and back up to the right hand side of the big sprocket. The weight is pulling down on both sides equally, the sprockets are joined so nothing happens. Imagine a weight being supported from a bar from an fan belt. There is equal pull on both sides. If you turn the bar the belt will go around. (The weight won't go up or down yet) Now we introduce the clever bit, the different size sprockets. Watch again after reading the above.

[@hillearybrown7083]

Hey Harvey thanks for the information! I couldn't work out how or why it did not fall back down, You turned the light bulb on

[@oooooooooorly]

A slight correction: there's equal "pull" on both sides in terms of force, but the net torque on the pulley assembly is nonzero because the lever-arms are different lengths (since the pulleys have different radii). So, if the system were frictionless, anything attached to the hoist would indeed lower itself under its own weight. The thing is, with a small difference in radii (i.e. large mechanical advantage), the torque induced on the pulley by the weight of the object is not large enough to overcome friction, and so it does not move.

[@danfloyd695]

Mr. Pete: I worked in a building that had an elevator that worked on that principle. It used a 1 1/2 inch rope. Going up was fairly easy even with a full load, but I can also remember coming down in a hurry and getting a rope burn as I hauled as fast as I could on that rope. This building was over 100 years old, and the hoist still worked well. Except for replacing the rope, which,by the time I retired was well worn, everything was original.

[@mrpete222]

+Dan Floyd Thanks for watching

[@SedatedByLife]

Holy cow! I have the 1 ton differential hoist (same manufacturer) I got from my buddy's grandma's house when she passed away and just finished restoring it (was out in the elements for years and super rusted). I wasn't sure if I put it together right but apparently I did! Can't wait to put it to use.

[@mrpete222]

👍

[@pnq8787]

This looks to be the only video of a differential hoist on youtube. Thank you, sir!

[@AmateurRedneckWorkshop]

That was very interesting and you continue to have more instruction in your videos than anyone else. Thanks for the video.

[@mrpete222]

+cerberus Thanks for watching

[@DwayneRouthierJr]

no math? some people know it all I guess, or maybe they don't know what's go for'em. I really enjoy the math! I've watched a good majority of your videos... some 2-3 times. you have a very unique way of teaching and its what I need to learn. I'd just like to say thank you for all the time and effort you dedicate to these videos and teaching. thanks Mr. Pete.

[@mrpete222]

+Dwayne Routhier Jr No math-thanks for watching

[@johnjohn-ed9qt]

+Dwayne Routhier Jr The math is easy. Each turn of the top shive set rolls 24 links (on mine) on the large shive, and 22 links on the small. Each 24 links on the hand chain side shortens the lift loop by two links, one on each side of the lift fall. This means that 24 links pulled lifts by one link, for 24-1 ratio. Friction on the pins holds it in place.

[@Kris_at_WhiteOaksFarm]

So much beauty in simple mechanics. Thank you!

[@mrpete222]

+Kris Gasteiger Thanks for watching

[@farerse]

love this, simple to understand and interesting.

[@mrpete222]

+farerse Thanks for watching

[@Metallurg33]

Thanks again for the thought & effort you put into these videos.

[@mrpete222]

+Metallurg33 Thanks for watching

[@danburns3097]

Fantastic video!! Thank you for sharing so much! I have an antique D. Round And Son Little Wizard differential hoist that I'm trying to piece together and couldn't quite figure out the chain rigging. Your video will help me getting my hoist working for me! Thanks again!

[@mrpete222]

👍👍👍

[@jimmilne19]

Liked and appreciated, enjoyed and learned from. Gets not much better than that. Thanks. The never ending story of mankind ingenious.

[@mrpete222]

+Jim Milne Thanks for watching

[@idontknow2293]

Thank YOU. Excellent video. I just remembered where I've seen this type of hoist. It was used as A backup for an overhead garage door in case of A power outage. Probably still is.

[@mrpete222]

Yes

[@austinwagoncompany]

I'd like to see how to keep the chain from binding up on the lower pulley. I'm having a hard time keeping them straight.

[@MrUbiquitousTech]

That's interesting, and you can see the design relation to the Chinese Windlass. I have one of these differential hoists somewhere. Haven't used it in over 20 years though. Pulled many an engine with it then got a cherry picker. The hoist was faster than the cherry picker though, just don't have any rafters to strap it to at this house. After watching this video I may dig it out; never studied it, just used it. Thanks for sharing Mr. Pete!

[@mrpete222]

+ShysterLawyer Thanks for watching

[@straightpipec6099]

I just picked up one of these. Glad I found your video. Thanks.

[@mrpete222]

👍

[@Newmachinist]

Thank you Mr. Pete !! It may not have the best ratio (ie lots of pull for small travel) but the control is excellent. Wish I had it when I mounted my lathe onto it's stand. Thanks for the explanation.

[@mrpete222]

+Newmachinist Thanks for watching

[@tommyhanlon8012]

Excellent Mr.Pete, ...Thanks yet again.

[@mrpete222]

+tommy hanlon Thanks for watching

[@MrHevyshevy]

My eight year old enjoyed this. And pointed out to me we have one just like it in the shop. I enjoyed it too.

[@mrpete222]

+MrHevyshevy Thanks for watching

[@77appyi]

i do have one but yet to use it as one of the disadvantages is the loss of height as it takes a lot of room, with the 2 sets of pulleys, my lifting beam is only 11 or 12 feet up which sounds plenty but soon disappears when lifting bulky items of a trailer or a cab off a tractor..my felco 3/4 tone chain block is about the size of your bottom pully probably saving at least a foot..the advantage of the differential lift is the smooth transition from up and down ..some of the geared blocks you have to jerk the chain to start lowering it..i do have a nice worm and wheel hoist that works nicely from up to down but it also has 2 falls of the chain so a bottom pully on the hook so loses a lot of space as well

[@jefffrayer8238]

I finally looked at the chain hoist hanging in my late FIL's polebarn. Exactly the same as yours but the main frames are aluminum instead of cast iron with plain aluminum finish. Both pulleys are cast iron but mounted in cast aluminum. Capicity 1000 lbs is cast exact same as shown. Instead of saying Coffing Hoist Co., Danville Ind. mine says " -TIMKEN- " then " ROLLER HOOK " . Timken in place of Coffing, and Roller in place of Danville. I suspect it came from Grand Trunk where he retired from. Nice video.

[@mrpete222]

Thank you, very interesting

[@stefantrethan]

That's quite nice. I like that you can see just how it works right from the outside. Those geared hoists I don't trust - who knows what condition the gears are in or if they are made from hard cheese instead of steel. With this one as long as the pockets are not worn it will be fine. Thanks for showing this, and the chinese windlass. I thought this would be a boring topic, but it was just the opposite.

[@mrpete222]

+stefantrethan Thank you

[@danbreyfogle8486]

I have two of this style hoists but I still don't understand why it doesn't drop the weight when you let go of the chain. I have used mine for different lifting projects and am impressed with the ease of lifting and surprise it hold the load.

[@XGD]

Maybe the weight of the chain is enough to barely hold the load in place. It probably all comes down to the mathematics of it

[@w056007568]

Excellent video with very clear explanation and practical demonstration.

[@mrpete222]

+Dan Whiteford Thanks for watching

[@SteamerEdge]

Great Video, definitely made me think, isn't it amazing how very simple designs are the most effective ones. The model made it all crystal clear ..

[@mrpete222]

+SteamerEdge Thanks for watching

[@RPMechanics]

Another great video in this series. Looking forward to more. Thanks.

[@mrpete222]

+RP Mechanics Thanks for watching

[@thebigchuckster]

you've just shown me the ideal project for building with my son! he loves all things crane-related and this will be the seed for a bunch of hand-powered lifting machines :)

[@mrpete222]

+Charles de Voil Great--have him build one--hes showing a mechanical interest

[@TheMainlinehobo]

Mr Pete, These last couple of winch/windlass videos were fascinating! I really mean it. I've been a long-time subscriber and find all of your videos really great, but this was really a terrific eye-opening discovery for me. Well done! Wondering if this was somehow an old technology that perhaps was used back in the days of building the pyramids, etc? All the best, Mainlinehobo.

[@mrpete222]

+RL Fort Thanks for watching

[@WideVisionMetalFab]

The roller chain model really made it clear for me! Thanks!

[@mrpete222]

+Wide Vision Metal Fab Thanks for watching

[@TractorWrangler01]

I have one almost exactly like that made by American Chain and Cable company. 1/2 ton also. Love it. I honestly think it would exceed its rated capacity significantly although I havent tested that theory. I think it would only be limited by the weight of the person operating it times 2 people probably. So what ever a 300ish lb pull could do. Its an amazing little gadget. My neighbor borrowed it to pull a small v8 engine out of an old Chevy Nova and had the front wheels of the car off the ground because he forgot to unbolt the motor mounts. I dont know how much that weighed but it has to be over its rated capacity I would think. Very nice chain hoist.

[@mrpete222]

They are really neat mechanisms

[@jeremyrock9305]

Thanks for the info I just was given an old differential hoist from a neighbor it’s a 1000 lb one but it’s pretty old !

[@MrGoosePit]

Great explanation Mr Pete. Very interesting!

[@mrpete222]

+MrGoosePit Thanks for watching

[@springwoodcottage4248]

One of my favourite tools, makes one feel like a giant being able to move heavy weights so easily.

[@mrpete222]

+Springwood Cottage Thank you

[@rand1262]

nice job. i have used chain falls in my line of work, but not that type. interesting to see how they work. thank you.

[@mrpete222]

+Rand Fournier Thanks for watching

[@ARVash]

I really loved this video, what a marvel this thing is. Very cool

[@mrpete222]

+Alan Ball Thank you

[@jamesacker7343]

I have a hoist that looks just like yours. I've had it since the seventies.I know it's much h older than that. I de-rusted it painted it red. It is 1/4 ton and was made by Chisholm & Moore in Cleveland Ohio

[@levinorthover5727]

I was thinking in my head before you said I'm pretty sure my buddy's dad has one of these old hoist in there barn as a engine hoist or lifting other parts on while working on tractors

[@harveysmith100]

Thank you so much for this video. It seems such a simply thing but I have puzzled most of my adult life at how these work. I have used the chain type to open warehouse type roll up doors and I think I have used a rope type in a dumb waiter which I remember thinking was so simply but brilliant.

[@mrpete222]

+Harvey Smith Thanks for watching--yes, very ingenious

[@rob16268]

For me. Was you best video as of late. Thanks!

[@bobrees4363]

Trust me a 1,000 lb chain hoist like the one in Mr. Pete's video will lift the front end of a 66 Dodge one ton completely off the ground, (and the 200 lb Sailor standing on the bumper operating said hoist) when you don't take out the transmission to bellhousing bolts instead of the bellhousing to engine bolts. I was helping my dad do an engine swap on his work truck while home on leave. The Dodge bellhousing went down behind the flywheel so it had to come out with the engine, instead of being open in the front like on the plethora of Ford and Chevy's that I had experience with.

[@stephendumaine1575]

cool! i was just gifted and old differential hoist. eager to hang it in my shop!

[@mrpete222]

Great

[@tomuchfunwithgas846]

Thanks, things I forgot I knew. Love this type of information. Denny

[@oldman6495]

Thank you for bringing back some fond memories, of a simpler time, and reminding me how old I am! LOL

[@HammerandNeil]

NIce explanantion! Jimmy Diresta suggested this channel!

[@davidbarnhart6228]

Just discovering this vid Mr. Pete! That was very interesting.👍

[@mrpete222]

Thanks for watching

[@JeffreyVastine]

Mr. Pete, thanks for another great video.

[@mrpete222]

+Jeffrey Vastine Thank you

[@johnstrange6799]

Wow! I am at this moment just coming from making a Chinese Windless as I learned from the last video. I used an old shoulder drill as the crank mechanism. :)

[@mrpete222]

+John Strange Thanks for watching

[@jix177]

Great explanation + demo. What keeps the weight from winding back down? Is it basically friction and the ratio of input:output gearing?

[@mrpete222]

+jix177 Thanks for watching

[@ZeusOnDaLoose]

Is the square bolt in the center of both sprockets, position locking brakes? Thx 🙏 great video.

[@bowlineobama]

Awesome. Love it . Where can I get one of those Differential Hoists like the one you have?

[@millomweb]

I can't believe these aren't far more common - absolutely everywhere. Such a simple and effective design....... ...just short of an electric motor ;)

[@jazzGT]

cool this was exactly what i was looking for!! great video!

[@literoadie3502]

I find the differential hoist really appealing. I will build one one day once I have a mill and lathe. These show up on eBay from time to time but they're quite rusty. A new shiny one out of steel with some heavy capacity chain and nice lifting hardware would be a nice piece to have. Now I wonder where I can find a a loop of high capacity (say 10 000 lb?) endless chain?

[@mrpete222]

Very cool!

[@literoadie3502]

@@mrpete222 Hopefully I'll show it to you once it's built! Thanks for the videos Mr Pete

[@bwalbwal7895]

Great video. I wish I had you as a school or tech teacher.

[@mrfarmall-vk4gw]

I have one of these in my work shop mounted to a home made jib crane, it will easily lift a tractor engine and i can then swing it around the shop

[@Emtbtoday]

Hi great video! I've got a ww2 german one from a pilson hoist from a bergepanzer recovery vehicle it's basically the same but only one runner at the top with the wheel on the side as a separate chain I'm trying to figure out how this works I worked it out before how to feed the chain through correctly but been so long I've completely forgotten! The top disc sits across and the second wheel sits on the side with a worm going through turning the bigger pully with the smaller pully hook

[@tolydukhovny682]

excellent topic? mr. peterson! made me think abit. it holds due to the fact that no pulley or shaft can run with two different angular speed at the same time! beautiful old machine. thank you very much for the video, -toly

[@thecorbies]

+Toly Dukhovny Hi. If you look back at Tubalcain's video about the Chinese windlass, you'll see that there was a comment from a viewer referring to the fact that actually it works only because of the inherent friction in the system. If you think about it a bit further, you'll appreciate that the pull on one side is very slightly more or less than the other side. More friction than difference in effort presides and the pulleys/sprockets stay put. So, sometimes friction IS an advantage haha.

[@ExtantFrodo2]

+thecorbies Try walking with no friction.

[@asherdie]

+ExtantFrodo2 space walk?

[@ExtantFrodo2]

grumpybill Yup, in that situation walking doesn't get you very far. And yet zero g does not mean zero friction. Think lunar walking difficulty as the power of the stride was greater than the accustomed friction of the foot with the ground. Their feet would slide out from under them. If we evolved in lunar gravity we'd have either much larger feet or ones that were not as smooth (or both). Friction is also good for lighting matches, stopping cars, keeping furniture from wandering around the room,....

[@asherdie]

+ExtantFrodo2 you believe in a moon landing? bwahahaha

[@MaineGeezer]

I love the elegant mechanical simplicity of these things. I don't understand why they aren't made anymore. I assume there is a reason the more complicated geared chain hoists have taken over, but I don't know what it might be. I'm going to see if I can build a working model that uses #4 machine chain. Maximum load limit for #4 chain is about 215 pounds, and of course it is "not for overhead lifting," but it ought to work to lift my 65 pound rotary table on and off the milling machine and things like that. Do you have any thoughts about traps for the unwary that I might encounter? I just made a wood wheel with chain pockets as "proof of concept" to see if I could get the size of the pockets correct for smooth operation. I discovered that the best working size varied about 6% from what I had calculated, so there is a certain amount of the Unknown involved...enough to keep it interesting.

[@mrpete222]

👍👍👍

[@MaineGeezer]

Well, I've got Version 1 mostly completed and working. I don't see any way to include a picture with a comment. If anybody knows how, please enlighten me. The most difficult part, which I still haven't completely figured out, is getting the entrance and exit ramps for the chain link pockets correct. I assume they are supposed to be something like an involute...but they aren't, because the thing "unwinding" from the circle and tracing the path is not a continuously flexible string, which the definition of an involute calls for. Instead there is what amount to a series of rigid hinged bars, which is not the same thing at all, hinging up and off in sequence. I think the thing one needs to do is find a circular approximation that is "close enough." Even given that, however, it's not at all clear how one would cut the pockets to that curve. I've got the pulleys so they work, but the chain travel is slightly bumpy. I used counts of 16 links and 20 links on the pulleys, which gives a 10:1 reduction. At that ratio, it is barely self-holding. If I build a V2 I may try 18 and 20, which would give 20:1

[@MaineGeezer]

For anyone interested, a description of how I built one is being serialized in "Machinist's Workshop" from Village Press, June/July 2022. I was never able to get the chain to run over the pulleys as well as I would have liked. I think the shape of the links in the #4 machine chain I used is simply not designed for such an application. The links need to be specifically designed to resist tangling. It was an interesting project though, and I use it to lift my 65-pound rotary table on and off my milling machine. Some have asked, "what keeps the load from dropping when you let go?" and the answer is, "internal friction and luck." I don't think one should count on one of these things being self-holding. If circumstances happen to create a very low-friction condition, the load will drop. You have the reduction ratio working in your favor, but that is not sufficient to guarantee anything.

[@WAVETUBE84]

Tom LIpton (OXTOOL) has a few videos (part of his printing press series) that have a "Cycloidal" reduction gear train. It is similar to a planetary reduction gear train. Deep in the internet, there is some manufacturer that makes a chain lift that uses the "inter-cycloidal" reduction gear train.

[@mrpete222]

+WAVETUBE84 Thanks for watching

[@not2fast4u2c]

My Dad had a chain hoist like that ...And a 50 lb. scale weight like yours ..I used to lift it over my head with one hand to impress the neighbor kids

[@mrpete222]

+not2fast4u2c Thanks for watching

[@learningtolive3498]

thanks for the good video. i was not sure how to thread the chain!

[@xxrodneyxx]

Thank you Mr. Pete

[@1973mre]

I really like this series keep up the good work

[@mrpete222]

+1973mre Thanks for watching

[@edwardhumbert7789]

I have one exactly like this (1000 lb) but it looks like aluminum and it’s made by another company. Is it possible to use it to remove a tree stump?

[@candelariosanchez273]

Very interesting well explained thx!

[@davida1hiwaaynet]

Very nice hoist! That Coffing chainfall will be alive and well long after my Harbor Freight electric hoist is dead and gone. :)

[@mrpete222]

+davida1hiwaaynet true- Thanks for watching

[@jarrettguthrie1670]

My guess is that this stays in place because of the mechanical advantage of the weight of the chain on the larger sheave? Otherwise it's wizardry.

[@ukfhjmvhj]

Thanks for the info, it was very helpfull

[@robs9574]

Would this work for two capstans of different radii locked together? Three or more turns of rope on each. Would be like a hybrid between the Chinese Windlass and Endless Chain but the rope would not be endless. It would instead pay out of a rope bag through the system and then to load. If that worked could one make it from two different tire rims? Guessing that a pulley would have to split the work of the two drums at the load. System would be for lifting or pulling only. Thanks.

[@patrickwhitehead7584]

Your videos are fantastic. So I live in northern Illinois and work as an industrial mechanic. I'm wanting to learn more about machine work and get some practice. I was thinking that maybe the rail museum in Union might be a good place to look, but maybe you have some insight.

[@mrpete222]

+Patrick Whitehead Yes-go there-did you see my recent video on same?

[@patrickwhitehead7584]

+mrpete222 I have not, but will look for it. I used to go there as a kid- I think it was around the time of the first gulf war I was there last. Also, I found this on Craigslist in Madison. Does that seem over priced to you? madison.craigslist.org/tls/5272258394.html

[@mrpete222]

+Patrick Whitehead That lathe is a beauty. Price is a little high. Try for 1400 or 1500. If he balks, take it for full price

[@hopper1]

Things like this make wish I could go back to shop class.

[@mrpete222]

+hopper1 Thanks for watching

[@pierresgarage2687]

That shows how the best inventions are always the simplest principles applied to daily life.... ;)

[@mrpete222]

+pierre beaudry Thanks for watching

[@christophernewton2579]

Mr Pete in a future video can you go over the differance between a tool room lathe and a regular lathe. Have you already made one?

[@metaling1]

Thank you, as always tubulcain

[@mrpete222]

+metaling1 Thanks for watching

[@millomweb]

5:00 Size difference in 'sprockets' - is it the case where the smaller one has one fewer 'pockets' around the circumference than the larger one ?

[@69uremum]

A pulley is also sometimes referred to as a sheave not a shiv.

[@ccfoam]

Interesting video.... I have a favor to ask. I came upon a KOETT tool post grinder last week. I can find no info. An old timer from PRACTICAL MACHINIST forum said it was the CADDILAC of tool post grinders. I posted some pics of it on Adam Booths facebook page last week. Question I have concerns the flat drive belt. Two identical length belts came with the grinder. Problem is that when the belt length will only work with the a couple of smaller pulley combinations. The belts have very little stretch, not like a rubber band. Does your DUMORE have multiple belts or does it allow you to pivot the motor to tighten the belt? Have a great day Mr. Pete....Chuck Castiglione Greenville, PA.

[@mrpete222]

+Chuck Castiglione My big dumore uses a standard v belt. The 2 smaller ones use little flat belts with no stretch. I have never seen a KOETT.

[@Blazer02LS]

+Chuck Castiglione Does it look like this one? www.freepatentsonline.com/2453020.pdf

[@leehutson340]

What causes the braking effect? You didn't explain what keeps the weight suspended and not going back down

[@kevCarrico]

another great video!! how high can the joker lift the weight on the model hoist? :)

[@clifffiftytwo]

Could a third sprocket be added to the top for more mechanical advantage? Would that require a second bottom pulley, perhaps a fixed one attached to the floor? I know my question goes where you're trying to avoid, but I see this as a mechanical computer in addition to a useful shop tool.

[@mrpete222]

+Cliff Miller Thanks for watching

[@LutzDerLurch]

No need to. you can get the most brutal mechanical advantage, by making the difference between the two sprockets' diameter amller and smaller

[@timpadrick9669]

I think it's not the difference in the sprocket radii, but the difference in the radii of the chain pockets - this difference is a lot more than the difference in the sprocket sizes.

[@UnbeltedSundew]

So the reason it stays in the air is because both chains down to the pulley are coming off the opposite sides of the sprocket and because the sprocket is a single unit and they cant slip they counter act their own pull. It's really kinda brilliant. I always just assumed my chain hoist used a break of some sort to do that but obviously this makes a lot more sense.

[@thecorbies]

+UnbeltedSundew Hi. If you look back at Tubalcain's video about the Chinese windlass, you'll see that there was a comment from a viewer referring to the fact that actually it works only because of the inherent friction in the system. If you think about it a bit further, you'll appreciate that the pull on one side is very slightly more or less than the other side. More friction than difference in effort presides and the pulleys/sprockets stay put. So, sometimes friction IS an advantage haha.

[@MrUbiquitousTech]

+thecorbies It has to be more than friction, look at the windlass video. Mr Pete physically pulls on the weight and it does not move. Being just a small bench model his strength would have far overcome any friction in the device. Also, when lowering a load, an engine for example, the motion would overcome the friction and the load would rapidly drop, but in reality it never does and stops every time the operator does no matter how quickly he was going. I believe UnbeltedSundew is correct in his observation that it's the chain and sprockets working against each other that secures the load.

[@UnbeltedSundew]

thecorbies I don't believe there is a leverage advantage at all between the different sized wheels. I couldn't begin to give you an explanation why though. The fact must be that it is the same level of force applied to both sides of the wheel. I watched the Chinese windlass video (after this one) and you'll note that when the string is on the same size wheel the load doesn't move, I think this is significant... Perhaps because the load is hanging it equalizes the force on each line in oppositionally to the leverage advantage they would otherwise have?

[@mrpete222]

+UnbeltedSundew Thanks for watching

[@ianclapham3579]

Great job

[@mrpete222]

+Dave Jones Thanks for watching

[@chuckh.2227]

Very cool

[@joeljones3294]

mr pete what happens if the hook is on the pull chain side instead?

[@jefferylegere]

so why did they stop making these? seems just as effective as the current production chain hoists, but less complicated to build.

[@milesmetcalfe94]

My guess, there is no protection to stop you overloading the hoist and having a potential failure, modern style chain blocks have a clutch system to prevent an overload of the system.

[@tropifiori]

My wife has been baking a lot lately, so i’d Better get one.