Hey Adam, just a tip on spray adhesives. Spray both surfaces then let it flash for 30 minutes for it to get tacky and not sticking to your fingers. Then you press them together and it is done. Same with weather strip adhesive and vinyl tops etc.
100% thank you for the friend that would fix a surface grinder, that took a fall. The machinist community continues to amaze me, and all i can say is.. When you help someone.. without expectation of repayment. you might be amazed at what others will do for you..
Now this is a really nerdy point. In the video @15:30, it appears that the support pads are positioned symmetrically along the long axis of the rectangular plate. However, this is not the optimum arrangement of three supports for minimum distortion of the plate. With a symmetrical arrangement, the single pad at one end carries the same load as the other pair carry in total. Thus there will be greater deflection of the plate associated with the larger reaction force provided by the single pad. Rather, the single pad needs to closer to its end of the plate than the pair of pads are to their end of the plate. The determination of the optimum arrangement is not an easy problem. The paper in the link below suggests that the single pad should be about 17% of the length of the plate in from its end and the pair of pads should be about 28% in from the other end. In the other direction, the optimum positions for the pair of pads is about 28% of the width of the pate on either side of the long axis. I am sure none of this matters for how Adam with use the plate, but Lance obviously takes great delight in making things as precise and accurate as possible. Of course once the plate is lapped flat on a particular layout of supports, the arrangement doesn't matter provided that the support arrangement isn't subsequently changed. Great video as usual. Cheers www.witpress.com/Secure/elibrary/papers/LAMDAMAP97/LAMDAMAP97030FU.pdf
Do they make surface plates that are just equilateral triangles instead of rectangles or squares? Would make them awkward in term of usable space, but seems like it would be very stable.
I posted the reply below a day after your comment but didn't see it until now. Perhaps it best resides under your comment. I would hope the OEM knew where those points should be. The folks at "Quality Digest" did a great piece on Surface Plates some 15 or 20 years ago. It would be a great add on your link. "I won't (or shouldn't) say what lab it was in, but I was told by technician from Starrett Strategic that not only should a granite plate be on a 3 point mount system but they should be on the same 3 points used when the manufacturer created the plate. Ours were huge and probably 18" thick, so I never saw the bottom. Are the bottoms of these plates clearly marked as to those 3 original points?"
@@ramosel The paper in the link, which dates from 1997, says that at that time there was no standardized layout for plate supports. Rather, the recommended locations varied between manufacturers. As you note, provided that the support locations are are not changed from when it is lapped flat, within reason, it doesn't matter what locations are used, just so long as they stay the same. However, the locations that produce minimum distortion would also generally minimize stress due to the self-weight of the plate and therefore assist with longer term stability. But as I said, its a nerdy point, but I thought it might interest Lance as he seems to delight in gnat's whisker precision for its own sake. I did a rough calculation of the instantaneous elastic deflection of a 4'' slab of granite cantilevering 12" from a central support. The sag from the support to the edge should be of the order of 25 millionths, That is about one quarter of the overall variation that Lance quoted for an AA plate of that size. So replacing a plate wrong-way-around on its three supports would definitely mess with its accuracy. I don't know if the support locations are marked by the manufacturers, but if a plate is re-lapped such as Adam's plate, the support positions should be marked so that the plate can always be replaced in the same orientation. An equally satisfactory kinematic alternative to three supports would be a symmetrical layout of four supports with two adjacent pads located on the ends of a centrally pivoted bar. Cheers
My OCD wanted to see you clean up the rust on that old frame and seal it with some metal paint, nice and shiney... I know you won't see it after the granite block when it is back in there... but... you know... OCD... anyway awesome to see the process done, look forward to part 2
@@stargazer7644 YES... We *ALL* will know... so in part 2 let's see if Adam bows to the pressure of UA-cam commenters to clean it up... reluctantly... LOL 😁
You're supposed to spray both sides and let it tack up for the recommended amount of time on the can, usually 20 and 30 minutes, it will feel slightly tacky when ready. If you put it on there while "wet", it may never cure, it needs open-air to tack up. People I know have used it on laminate, just sprayed it on and put it up temporarily securing it with tape, it fell off days later because it never cured.
I'm looking forward to seeing the lapping done. About 25 years ago I saw it done by a Starrett plate lapper using a pair of pendula. and having had a class on hand scraping I understood a little of it, but not enough. It won't hurt me to see another method being used..
I'm reminded of when you took that scraping course a couple years ago and how he stressed the importance of checking your work against a known flat surface.
After owning a bottling plant for years I just stoped trying to bond UHMW. In my experience it cannot be bonded without special surface conditioning, due to the high degree of polymer chain alignment and hydrogen pairing on the surface. Did the spay you used actually work?
Spray glue is about the only thing that halfway works on polyethylene. But, he only needs it to stay in place long enough to set the stone, gravity will hold it in pkace
With UHMW it has to be hit with an abrasive and usually flame etched. Then there is only one glue I ever found that sort of works. I think it was called (Bond It ) or something like that. It is an epoxy that uses the tertiary hydrogen to help form a bond.
That spray adhesive ain't gonna stick to UHMW probably. You need some low surface energy adhesive. I'd have done a counterbore to sit the pad in so it doesn't slip off the surface
Consider using a telescope mirror-mount type of suspension, which can be three points suspended on three points, etc., so that a lot of even support is given. A telescope mirror's tolerances are exceedingly tight, measured in fractions of a certain wavelength of light, which would be sub-micron.
While the idea of the wheels is good, makes the plate movable, would it make sense to have some solid feet so the plate cannot move around. Or Does it not matter in this application?
I guess that the granite surface plate will sag slightly under its own weight between the supports. So, exactly where should those 3 supports be placed under that rectangular prism of granite so that the top surface flatness is maintained as good as possible over the entire area?
From the Starrett website " A surface plate should be supported at 3 points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered. Only 3 points can rest solidly on anything but a precision surface."
No criticism. I don't know enough for that. Just a question. If the uhmw-pe selected for its low friction properties, why glue on the rubber discs to add friction at the end? Interesting videos as usual. Thank you.
Why didn't you bother to clean up and paint the frame of the granite table before you reinstalled the granite? Seems like it was the perfect opportunity to get rid of the rust and put on a new coat of paint.
Adam, was that a Monarch 10EE lathe you made the uhmw pads on? We have a short one in our shop, the most accurate machine we have, even at 70 years old.
@@Mr.Potato420 From the high mountain desert, Anything with 100% Humidity sucks, but now I know why I was getting funny looks from floridians as I was walking around in my shorts and teeshirt.
@@WraithlingRavenchild if it's constantly cold I can get used to it and walk around in flip flops but when it's this time a year and one day the high is 50 and the next day it's 90 it fucks with you.
Could someone explain the rationale behind the 3 points of contact? I went googling The American Society of Mechanical Engineers but all I could find was about ladders and safety.
SAME REASON MILK STOOLS HAVE THREE LEGS, IT WILL NOT ROCK ON UNEVEN FLOOR, OR STONE. MASTER STONE WILL NOT ROCK IF BASE IS NOT 100% EVEN ON ALL FOUR SIDES.
@@spwhateverable The replies have helped and your recommendation for what to search nailed just what I was looking for and has returned some really detailed sites. Thank you to all all the replies! 👍
How do you like the Alfa Tig 200. I've had one for about four years with no problems at all. I don't usually burn sticks with it, but I have just to test it. Be Careful and Stay Safe. Bob
@@danduane1413 A Toboggan Is a Hat to Southerners Here's what I found out on my end. From the research I've done, it appears that the southern region of the United States (the areas that use Southern American English) use the term toboggan to refer to a knit winter hat. This area includes the states of Virginia, North Carolina, South Carolina, Georgia, Alabama, Mississippi, Tennessee, Arkansas, Louisiana, Kentucky, and Texas. It may also include specific regions of Oklahoma, Missouri, Maryland, West Virginia, Florida, southern Indiana, and New Mexico.
@@philipmackin1025 FELLOW EDMONTONIAN! \o/ I'm sick of this weather too. February was absolutely frikken brutal, but it always is. -40 for 3 weeks... D:
@@SnoDawg The funny thing is, in places that get REAL winter, a toboggan is a child's sled. What you're describing, a knit winter hat, is called a toque. en.wikipedia.org/wiki/Toboggan
From the Starrett website " A surface plate should be supported at 3 points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered. Only 3 points can rest solidly on anything but a precision surface."
@@madmodifier Was expecting a mention of 'Airy points' and how he worked out the positions of the holes in the tube and the location of the tubes on the frame.
I keep thinking back in the days of the Vidicon tube if you tried to video somebody welding with out heavy filtering you would instantly burn out the Vidicon tube.
Bar stools have three legs so that the "legless" patrons don't fall off them. It's also the reason that lathe and drill chucks have three jaws and the reason that 4 and 6 jaw chucks don't do what many folk expect them to do. Stavros
Three points is always stable, four you can have one point introducing a warp to the plate, or it could rock even minutely. Think of a three legged stool, steady as a rock, add a fourth leg and you are rocking and wobbling all over the place or if the stool body is weak enough the whole thing will flex under your weight.
You can use four points, vehicle weighing gauges, for example. But that is a completely different application. Supporting a plate, you would need to ensure that the weight carried by each point was the same, after levelling the whole thing. With a triangle, all you need to do is ensure the Centre of Gravity of the triangle is directly under the CoG of the plate. That evens up the weight carried. CoG of a triangle is where the three lines joining each side bisector with their opposite vertices meet. (OK I did just look that up to check!) As for the optimum shape and position of the triangle... I'm not sure why this is being done with two supports on one half of the plate, and only one on the other. But I can't work out why it upsets me. I just want it to be rotated, providing three supports in both the long and short axes. I would have thought that would be good to suppress bowing. As this is, there are only two points resisting bowing along the long axis, which is no support at all. On the other hand there are three along the short axis which is already the least susceptible to bowing. Perhaps when they get down to microns, what I'm talking about will matter!
This video is a bit misleading. Adam is establishing 3 pads of contact, but not points. If he thinks he is, he is mistaken. Each of those pads is its own plane. That said, what will happen is that the weight of the block will deform the plastic and create co-planar surfaces of each pad. A point of contact is a theoretical exercise in this case, and in almost all cases as materials deform under load and what was a point becomes a surface as the support material is deformed under load.
I'm not really familiar with UHMW, would that not deform, or sag under the weight of a granite slab over the years? Or does that even matter in this application?
You know my dad never use those terms but verify yeah I keep hearing a lot of that lately verify cool yeah everytime you go there it's always different slap my father go big or go home but when you call it too big is enough good video good education love it God bless👍🙏🎸
The reason for the three points of contact between the frame and the plate is to cancel the affects of any warping that the uneven floor could put into the plate. It's about flatness not stability.
That little Monarch lathe is beautiful restoration.
Hey Adam, just a tip on spray adhesives. Spray both surfaces then let it flash for 30 minutes for it to get tacky and not sticking to your fingers. Then you press them together and it is done. Same with weather strip adhesive and vinyl tops etc.
Something about your style is so relaxed and interesting. Gonna jump on and watch part 2 of this right now! Great video as always.
100% thank you for the friend that would fix a surface grinder, that took a fall. The machinist community continues to amaze me, and all i can say is.. When you help someone.. without expectation of repayment. you might be amazed at what others will do for you..
That Monarch lathe is beautiful. Probably looks better than the day it was shipped from the factory!
Wow, it is such great fun to see Adam back in another shop other than his own. Thanks Adam.
Love it when you spend time with Lance
That parting UHMW chip was pretty awesome.
Very informative/entertaining and especial thanks for breaking into two logical parts for those of us who ration and save the best for cocktail hour.
Now this is a really nerdy point. In the video @15:30, it appears that the support pads are positioned symmetrically along the long axis of the rectangular plate. However, this is not the optimum arrangement of three supports for minimum distortion of the plate. With a symmetrical arrangement, the single pad at one end carries the same load as the other pair carry in total. Thus there will be greater deflection of the plate associated with the larger reaction force provided by the single pad. Rather, the single pad needs to closer to its end of the plate than the pair of pads are to their end of the plate. The determination of the optimum arrangement is not an easy problem. The paper in the link below suggests that the single pad should be about 17% of the length of the plate in from its end and the pair of pads should be about 28% in from the other end. In the other direction, the optimum positions for the pair of pads is about 28% of the width of the pate on either side of the long axis. I am sure none of this matters for how Adam with use the plate, but Lance obviously takes great delight in making things as precise and accurate as possible. Of course once the plate is lapped flat on a particular layout of supports, the arrangement doesn't matter provided that the support arrangement isn't subsequently changed. Great video as usual. Cheers
www.witpress.com/Secure/elibrary/papers/LAMDAMAP97/LAMDAMAP97030FU.pdf
Do they make surface plates that are just equilateral triangles instead of rectangles or squares? Would make them awkward in term of usable space, but seems like it would be very stable.
I posted the reply below a day after your comment but didn't see it until now. Perhaps it best resides under your comment. I would hope the OEM knew where those points should be. The folks at "Quality Digest" did a great piece on Surface Plates some 15 or 20 years ago. It would be a great add on your link.
"I won't (or shouldn't) say what lab it was in, but I was told by technician from Starrett Strategic that not only should a granite plate be on a 3 point mount system but they should be on the same 3 points used when the manufacturer created the plate. Ours were huge and probably 18" thick, so I never saw the bottom. Are the bottoms of these plates clearly marked as to those 3 original points?"
@@ramosel The paper in the link, which dates from 1997, says that at that time there was no standardized layout for plate supports. Rather, the recommended locations varied between manufacturers. As you note, provided that the support locations are are not changed from when it is lapped flat, within reason, it doesn't matter what locations are used, just so long as they stay the same. However, the locations that produce minimum distortion would also generally minimize stress due to the self-weight of the plate and therefore assist with longer term stability. But as I said, its a nerdy point, but I thought it might interest Lance as he seems to delight in gnat's whisker precision for its own sake. I did a rough calculation of the instantaneous elastic deflection of a 4'' slab of granite cantilevering 12" from a central support. The sag from the support to the edge should be of the order of 25 millionths, That is about one quarter of the overall variation that Lance quoted for an AA plate of that size. So replacing a plate wrong-way-around on its three supports would definitely mess with its accuracy.
I don't know if the support locations are marked by the manufacturers, but if a plate is re-lapped such as Adam's plate, the support positions should be marked so that the plate can always be replaced in the same orientation. An equally satisfactory kinematic alternative to three supports would be a symmetrical layout of four supports with two adjacent pads located on the ends of a centrally pivoted bar. Cheers
I hear Robin Renzetti's name, couple seconds later, I hear "millionths".
Yup.
I love how people with similar interests but are not acquainted become friends.
Hello Adam,
A good show tonight... Lance has a very nice workshop...
Take care.
Paul,,
Adam grinning @ the end like a kid in a sweet shop, I would be too if i was working there.
some of the best videos are when these guys are together. Lance start a channel its time
My OCD wanted to see you clean up the rust on that old frame and seal it with some metal paint, nice and shiney... I know you won't see it after the granite block when it is back in there... but... you know... OCD... anyway awesome to see the process done, look forward to part 2
Every time we see that stand in the future, we'll all think about how cruddy it is under that stone.
@@stargazer7644 YES... We *ALL* will know... so in part 2 let's see if Adam bows to the pressure of UA-cam commenters to clean it up... reluctantly... LOL 😁
You're supposed to spray both sides and let it tack up for the recommended amount of time on the can, usually 20 and 30 minutes, it will feel slightly tacky when ready.
If you put it on there while "wet", it may never cure, it needs open-air to tack up. People I know have used it on laminate, just sprayed it on and put it up temporarily securing it with tape, it fell off days later because it never cured.
I'm looking forward to seeing the lapping done. About 25 years ago I saw it done by a Starrett plate lapper using a pair of pendula. and having had a class on hand scraping I understood a little of it, but not enough. It won't hurt me to see another method being used..
Phil is correct, one beautiful Monarch.
Woah, parting off that uhmw was crazy, looked like some weird kitchen appliance.
Nice blood blister on the thumb Adam. I wonder what kind of words came out of you on THAT day!
I used UHM-W to make suspension bushings for my e46 BMW ... worked really well ... rides great
Adam, video quality is ++++ - well done mate!
I'm reminded of when you took that scraping course a couple years ago and how he stressed the importance of checking your work against a known flat surface.
OMG look at that gorgeous Monarch
That Monarch is in beautiful condition, looks brand new.
Looking forward to the conclusion, thanks for the video🙂
Just watched Robin's video on this subject... Perfect timing!
You guys are just having fun!
the spray adhesive won't work on uhmw but in this application it doesn't really matter since gravity will hold the plate down
Serious. Spray adhesive on UHMW and the implication that they need a press fit to stay in place.
@@Orxenhorf There is no kill like overkill. Ha!
Adam - you guys look like brothers!!
Trabalhar em um lugar assim com esta vista anima muito!!!
Bom trabalho!!!
One thing I love a teacher telling the teacher love that stuff
A beautiful shop
thank you guys for sharing your skills with us awesome as always
That Monarch 10EE....... SWEET!
Wow - that Monach is beautiful.
After owning a bottling plant for years I just stoped trying to bond UHMW. In my experience it cannot be bonded without special surface conditioning, due to the high degree of polymer chain alignment and hydrogen pairing on the surface. Did the spay you used actually work?
I doubt it worked, bonding UHMW is non trivial, you're not going to do it with just an off the shelf spray adhesive.
Spray glue is about the only thing that halfway works on polyethylene. But, he only needs it to stay in place long enough to set the stone, gravity will hold it in pkace
I would have roughed em up on a coarse belt so that adhesive had something mechanical to grab onto.
With UHMW it has to be hit with an abrasive and usually flame etched. Then there is only one glue I ever found that sort of works. I think it was called (Bond It ) or something like that. It is an epoxy that uses the tertiary hydrogen to help form a bond.
That spray adhesive ain't gonna stick to UHMW probably. You need some low surface energy adhesive. I'd have done a counterbore to sit the pad in so it doesn't slip off the surface
I think that once the granite slab is sitting on those tiny pads. It is going to move.
Thanks for sharing with us Adam. 👍👍👏🏻👏🏻
Lots o cow pies! Must be interesting when people ask why the shop tools smell like a dairy. LOL
Common interests and mutual assistance will make work easier
LOVE THE SIZE OF THAT SHOP !!!!! WHO ELSE IS WITH ME ??
Consider using a telescope mirror-mount type of suspension, which can be three points suspended on three points, etc., so that a lot of even support is given. A telescope mirror's tolerances are exceedingly tight, measured in fractions of a certain wavelength of light, which would be sub-micron.
Love those Monarch 10EE lathes! Had 4 of them in one of the toolrooms I worked in.
While the idea of the wheels is good, makes the plate movable, would it make sense to have some solid feet so the plate cannot move around. Or Does it not matter in this application?
This lathe on 11:16 is a piece of art
I love seeing a bunch of machines rebuilding machines that can build more machines
nice stuff.. Love how Lance is always so mellow :)
Pretty impressive for a hobby-machinist with a profession as a vet :) Thumbs up
Sounds like an interesting week to come - Baited Breath!
I guess that the granite surface plate will sag slightly under its own weight between the supports. So, exactly where should those 3 supports be placed under that rectangular prism of granite so that the top surface flatness is maintained as good as possible over the entire area?
Nice Monarch Lathe Lance. I'm looking forward to receiving my set of precision stones, plenty of jobs for them straight away!!
The ultimate tool guys!
I thought Florida was warm, you guys are dressed for the northern winter.
Two questions, because I'm a noob.
Why 3 points of contact vs 4?
Why do people twist the electrode in the jaws while welding?
From the Starrett website " A surface plate should be supported at 3 points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered. Only 3 points can rest solidly on anything but a precision surface."
It can't wobble when supported from 3 points. Each point will have an equal load. 3 legged stools never rock.
No criticism. I don't know enough for that. Just a question. If the uhmw-pe selected for its low friction properties, why glue on the rubber discs to add friction at the end? Interesting videos as usual. Thank you.
When a guy voluntarily grabs a stick welder instead of a mig gun I'm impressed.
I have a 24x36x4 plate of questionable origin and no markings, how do you determine where the 3 supports are positioned?
Approx 1/3 of the length from both ends, you want the weight of the plate to balance across the points to avoid center sag.
Awesome i have been waiting new collaboration video with another who knows about STUFF
His shop sure filled up fast lol
I know right?
I love the little lathe. Need one that size.
Lap the slab on both sides now that you are at it :) Yes I understand the underside might be too rough for lapping.
That monarch!
Why didn't you bother to clean up and paint the frame of the granite table before you reinstalled the granite? Seems like it was the perfect opportunity to get rid of the rust and put on a new coat of paint.
I'm guessing he'll probably do all of that cleanup back at his shop. He's got to transport it back to his place after the granite is lapped.
That really bugged me too. Especially when he was hammering in those pucks and the dust/filings were going everywhere.
Weather is crazy. It has been above freezing during the day for a while in central Canada. One 14C day and all the snow not covered in sand melted.
Adam, was that a Monarch 10EE lathe you made the uhmw pads on? We have a short one in our shop, the most accurate machine we have, even at 70 years old.
Yeah, that's a Monarch and a pretty one at that
70 degrees in Maryland in March, Abom in Florida wearing Carhartt.
a few days ago it was fucking cold 50 degrees with 100% humidity sucks
@@Mr.Potato420 From the high mountain desert, Anything with 100% Humidity sucks, but now I know why I was getting funny looks from floridians as I was walking around in my shorts and teeshirt.
@@WraithlingRavenchild if it's constantly cold I can get used to it and walk around in flip flops but when it's this time a year and one day the high is 50 and the next day it's 90 it fucks with you.
I have seen it snow in Crestview Fl ,about 35 miles north of where they at!
That parting of that uhmw was totally awesome how it rolled up I know it’s probably bad to y’all machinist but to my simple self that was cool as crap
Looks good guys
Great content thanks for sharing
Could someone explain the rationale behind the 3 points of contact? I went googling The American Society of Mechanical Engineers but all I could find was about ladders and safety.
three point contact takes away the risk of rocking you could get with a four point contct
Three points keeps it from rocking if there are high and low spots on back, or if the stand isn't perfect.
SAME REASON MILK STOOLS HAVE THREE LEGS, IT WILL NOT ROCK ON UNEVEN FLOOR, OR STONE. MASTER STONE WILL NOT ROCK IF BASE IS NOT 100% EVEN ON ALL FOUR SIDES.
UA-cam deleting my comments, but google GGG-P-463c, AIRY POINTS, and BESSEL POINTS
@@spwhateverable The replies have helped and your recommendation for what to search nailed just what I was looking for and has returned some really detailed sites. Thank you to all all the replies! 👍
get your voltage just right and you can never go wrong with a good 7018 rod. good choice! I swear by 7018s and 6013s
How do you like the Alfa Tig 200. I've had one for about four years with no problems at all. I don't usually burn sticks with it, but I have just to test it.
Be Careful and Stay Safe.
Bob
Abom do a tune up on his monarch, in the video his spindle appeared to have a bit of run-out. Probably just needs the bearing chase tightened.
You guys wearing toboggans in Florida. LOL
wearing toboggans ....... huh? wtf is a toboggan?
@@danduane1413 A Toboggan Is a Hat to Southerners
Here's what I found out on my end. From the research I've done, it appears that the southern region of the United States (the areas that use Southern American English) use the term toboggan to refer to a knit winter hat. This area includes the states of Virginia, North Carolina, South Carolina, Georgia, Alabama, Mississippi, Tennessee, Arkansas, Louisiana, Kentucky, and Texas. It may also include specific regions of Oklahoma, Missouri, Maryland, West Virginia, Florida, southern Indiana, and New Mexico.
Been wearing my double knit touque outside since Oct 2020. Freaking cold and windy. Edmonton Alberta. -7C(19F) today
@@philipmackin1025 FELLOW EDMONTONIAN! \o/ I'm sick of this weather too. February was absolutely frikken brutal, but it always is. -40 for 3 weeks... D:
@@SnoDawg The funny thing is, in places that get REAL winter, a toboggan is a child's sled. What you're describing, a knit winter hat, is called a toque. en.wikipedia.org/wiki/Toboggan
Lance is getting quite the shop.
Where's the footage of you mangling that thumb? I see the effect just not the cause.
I''d like to know more about his building....
Why you need Carhartt in Florida?
Nice Monarch lathe ; why is the Jacobs chuck making noise ?
Excellent!!
A nice coat of paint ?
The camera you’re using has incredible resolution!
Why did you only put 3 pads? Why wouldn't you put 4? Just wondering. I love your videos.
From the Starrett website " A surface plate should be supported at 3 points, ideally located 20% of the length in from the ends of the plate. Two supports should be located 20% of the width in from the long sides, and the remaining support should be centered. Only 3 points can rest solidly on anything but a precision surface."
Mathematically, three points are required to define a plane surface.
Because 4 points can rock. 3 points can't. You don't want the stone twisting.
@@madmodifier Was expecting a mention of 'Airy points' and how he worked out the positions of the holes in the tube and the location of the tubes on the frame.
I keep thinking back in the days of the Vidicon tube if you tried to video somebody welding with out heavy filtering you would instantly burn out the Vidicon tube.
Ask the Apollo 12 astronauts about that...
Nice shop!
Its really so unfair. you guys are having ALL the fun. I was wondering about how you transport the granite after its all level.
just take it on your lap in the driver's seat and hold on tight ;)
Lance ever go to the Waldo flea market?
I hear a Red Shouldered Hawk
Bar stools have three legs so that the "legless" patrons don't fall off them. It's also the reason that lathe and drill chucks have three jaws and the reason that 4 and 6 jaw chucks don't do what many folk expect them to do.
Stavros
Like #329
Thanks for the video!
It's good to have great friends!
Adam, if I missed it, sorry. Why a three point mount instead of a four?
Three points is always stable, four you can have one point introducing a warp to the plate, or it could rock even minutely.
Think of a three legged stool, steady as a rock, add a fourth leg and you are rocking and wobbling all over the place or if the stool body is weak enough the whole thing will flex under your weight.
three points determine a plane.
You can use four points, vehicle weighing gauges, for example. But that is a completely different application. Supporting a plate, you would need to ensure that the weight carried by each point was the same, after levelling the whole thing.
With a triangle, all you need to do is ensure the Centre of Gravity of the triangle is directly under the CoG of the plate. That evens up the weight carried.
CoG of a triangle is where the three lines joining each side bisector with their opposite vertices meet. (OK I did just look that up to check!)
As for the optimum shape and position of the triangle... I'm not sure why this is being done with two supports on one half of the plate, and only one on the other. But I can't work out why it upsets me. I just want it to be rotated, providing three supports in both the long and short axes. I would have thought that would be good to suppress bowing. As this is, there are only two points resisting bowing along the long axis, which is no support at all. On the other hand there are three along the short axis which is already the least susceptible to bowing.
Perhaps when they get down to microns, what I'm talking about will matter!
This video is a bit misleading. Adam is establishing 3 pads of contact, but not points. If he thinks he is, he is mistaken. Each of those pads is its own plane. That said, what will happen is that the weight of the block will deform the plastic and create co-planar surfaces of each pad. A point of contact is a theoretical exercise in this case, and in almost all cases as materials deform under load and what was a point becomes a surface as the support material is deformed under load.
less work
cURVE bALL Im a regular of your site You do good work
I'm not really familiar with UHMW, would that not deform, or sag under the weight of a granite slab over the years? Or does that even matter in this application?
It doesn't matter as long as the slab doesnt touch the metal frame.
You know my dad never use those terms but verify yeah I keep hearing a lot of that lately verify cool yeah everytime you go there it's always different slap my father go big or go home but when you call it too big is enough good video good education love it God bless👍🙏🎸
Ultra-high-molecular-weight polyethylene
Is there beer? Fun!
With three points of contact on a 4 wheel cart haven't you just move the instability down to the wheels?
The reason for the three points of contact between the frame and the plate is to cancel the affects of any warping that the uneven floor could put into the plate. It's about flatness not stability.
There is flat and then there is Lance flat
No kidding. I was amazed after he said that surface grinder spindle was within 50 millionths, he's obsessed with precision.
@@NP-rh3dt that's standard runout on a surface grinder spindle. the nicer ones are within ten millionths.
@@SuperAWaC Wow really, I didn't know that. That's pretty insane.
@@NP-rh3dt
Wow that's a little better accuracy then my tape measure :))🤣