Wolpert Testor HT2a Hardness Tester

[Music] hey welcome back to this old hardness tester as you can see i finally got the hardness tester that i talked in my last shop talk shop tour finally up on the table cleaned it up and did some maintenance on it because there were a few things to be dealt with but did that first i built a table out of 45 millimeter aluminium extrusion i have a little bit of a construction here that i will show so cutting the aluminium extrusion to length i'm using a woodworking miter saw and a lubrication stick which is basically almost like a piece of beeswax that you push against the saw blade this helps lubricating the cut and prevents a build up edge on the saw blade but in general cutting aluminium with a carbide tipped woodworking blade is no problem at all it works very well and the cut comes out almost like a milled finish miniature forklift is good support for the miter saw to get it to a decent height when you assemble aluminum extrusion always deburr the edges otherwise you will end up with a lot of spots on your finished product that you can cut yourself also take care of the corners a wire brush finishes off and removes any remaining fine burs tapping the central hole with the tiny cordless drill this threaded hole is for the feet that the table will sit on my preferred way of assembling aluminum extrusion are those die cast brackets it's a very fast way you then have to drill or mill into the profiles themselves and they're just fast and very convenient if if you have to reconfigure your your product that you're building they are not the most rigid way of assembling um there are larger die cast angle brackets that are twice the leg length but in this case the 45 millimeter angle brackets were good enough the major forklift is also for assembly a very nice table because it's height adjustable mounting the the lower bracing and you can also see the feet already in place this is a close up of how the t-screws and nuts work in conjunction with the die cast brackets the screw the hammer head of the screws drops through the slot in the bracket and twists in place in the extrusion the top of the table consists of this is three layer plywood and cut to size and i doubled up the thickness using glue and screws just to to give the table a little bit more meat a single plate would have been enough but i didn't like the look of it so i took two pieces glued them on top of each other and after the glue up i ran the the track saw around the edges to clean up any misalignment between the two pieces of wood and here you see me cutting into a screw that's in the sacrificial board of my on my two saw horses oops also when doing a cut like this the dust extraction on a track saw does not work then i had to take apart some of the mechanics on the back here i have a little bit of a clip that shows how the mechanics operate in there this is the mechanism from the hardness tester that selects the stack of weights that's needed for a certain test and all this mechanism here is you have these fingers which are on these two pivots vertically here and you have this closing bar back here that's spring-loaded like this and it works like this normally you have this plate in front here with those plungers and those plungers just press against those fingers and select the height of weight the the stack of weights that's needed for the test and when you want another stack just press another button it works like this or this [Music] it's not foolproof you can for example press in two at once but that's a case of the problem is in front of the keyboard not a fault of the machine and when i got the machine this lock bar back here the spring-loaded lock bar was frozen up it was completely gunked up on the pivots up here there were dowel pins running in these casts top plates and there was just gunk in it and i took it apart i cleaned everything and i put it back together so it's nice and smooth moving again here is the weight stack you have the retaining plate then you have individual weights that need to go back in the machine in this order just upside down because i pulled them out like this and this is the retaining plate for the bottom and now we need to get the casting or the the selector frame back in here bolted in place get the weights back in and reconnect the linkage so this goes in here and of course it's wider than the cutout in the casting but fortunately we can engage all those fingers so now all of the fingers are depressed and we can drop this back in lift it up okay there we go since i had all of the fingers engaged it takes a little bit of force on the lock bar to get it uh get it disengaged again so now we drop the bottom retainer plate back in and we engage the lowest lock fingers and then we just stack the weights in and it might it might be a good idea to clean them so they do not stick together i'm not entirely sure if this can happen but better be safe sorry and we don't abrasive clean these weights they have a fairly precise weight this one is only aluminium so it's super light all the other ones are steel as far as i can tell and right now we're building the lightest possible stack because basically the whole stack is disconnected from the rest of the machine and they're nice and tapered on the underside so they stack very neat so this is the heaviest weight huh alrighty there we go that's the complete stack of weights back in the machine ow get the pull rod back through there i'm polishing the plungers that select the weight stack with some 30 micron polishing compound in the lathe just on a piece of kitchen paper and a few seconds or enough to to clean up any discoloration oxidation and slight rust on these parts and it's time to to reassemble the the weight stack selector it's just bolted in place with four sucker cap screws alignment is not critical here and here we see the mechanism back in operation so it's time to move the hardness tester in place it's about 180 kilograms so the miniature forklift once again helped a lot and here it's in its final place that's the final result one beautiful hardness tester that i that i horse traded against a a construction compactor this is a walpart test tour wallpad test tour with all paperwork since the machine has bought it had two owners of which one is the company that bought it originally and the second owner is my friend so i'm the third owner what is it it's a hardness test it can do harden in its current configuration it's primarily a rockwell hardness test it does test the hardness in rockwell c there are different classes of rockwell testing for hardness and rockwell is primarily used for through hardened pieces you don't use it on soft metals you don't use it on soft steel rockwell c starts at around 33 points rockwell c to make sense below that it's basically soft cheese you cannot use it on very thin pieces then you would use either vickers vickers hardness or brunel hardness then there is rockwell b which uses a ball but i don't have the proper diamond for it i have only the diamond for rockwell c and a wicker's diamond which is a pyramid shape on rockwell c we have a dial indicator here that directly reads the hardness you put your piece in here you do your preloading you select the right uh loading and this indicator which is basically a two micron per division indicator shows the hardness in a direct reading i'll show you show it to you we'll do some hardness testing today on vickers we have to use a microscope to measure the size of the indentation and then calculate in relationship to the force that we use the drawback is it's more work there are testing machines that have an optic integrated you do your testing and then the diamond swivels to the side and the optic a small optical comparator moves in and you can measure the size of your indentations right in the hardness test this one but i have a toolmaker's microscope so i can't do my vicus testing so we have the googly eyed hardness tester here we have a large hand wheel here which moves the table for our sample up and down and we have a table that we can take out this is a small sample table this needs to be in very good condition and i have this large sample table that definitely has never been used so this screws on here all the way very long thread so it screws on all the way and then you have a large sample table which i prefer not to use because for my parts the small sample table is usually good enough but if i have the need for a large sample table i have it so let's so this goes off and the small sample table drops back and then we can move the bellow back up like this up here we have a sleeve that screws on and off and behind this we have the diamond we are very careful with the diamond because those are expensive there's a little set screw and in the in addition it's held in with a magnet this surface here and this face here need to be absolutely clean there can not be any dust dirt burrs or oil even oil will make a problem um otherwise the the measurement will not be good because the tip can rock or saddle under load or anything else where it can happen you'll just get an unreliable result in my experience so far which is about an hour on this machine i just dropped the magnet at the diamond in up against the magnet so it holds it and then i tighten the set screw just with my fingers just so it's very secure in there you can see this is moving and the weight stack and back of the machine that you saw me earlier fixing will press this diamond down and we have to screw on sleeve this has two purposes well it has one purpose and one benefit for one so that's normal use with the diamond down here exposed the side benefit is you screw it down a little bit and your your diamond is not exposed anymore so it's protected cannot fall out and it's very safe the diamond is multi hundred euros a piece so uh we better be careful with it and the second use is once you have your part here and preloaded with the diamond you can very very carefully settle this down onto the the surface of the part to even to even more stabilize the measurement we have the weight selector back here which uh reads in kilogram which is not a force but a mass but uh yeah we have 150 kilograms of force on the diamond that's for rockwell c we have 178.5 and 250 is the maximum and the lowest weight we can do is six two five which is uh probably for wicca's or brunel but uh we're rockwell c so we'll stay here select this weight and we have a second control we have this ladder down here which can be disengaged like this and then very slowly moves upwards and the same way this moves up the diamond moves down the speed is regulated by an oil dampening system in the side of the machine there is a little hydraulic cylinder with a valve and this reduces the speed of the stack of weights falling down with the lever down you you lift the stack back up and are ready to test again i have a high speed steel blank here which is as we know rather hard i have my precision ground flat stones here we stone the back a little bit just to make sure there are no high spots and we stone the table very lightly just to make sure there is no dings dents or bumps in it and we get our part on here we expose the diamond it is we raise the table with the work piece into the diamond now is the right time to find a good spot for hardness testing i did some hardness testing on this blank before so we have to find a spot that's clean and then we drop the diamond onto it and crank the diamond into it and how far do we crank it in we crank it in until the large needle stops moving that's about when the small needle points at this at the red dot here if i crank it up one two it's usually two and a half turns uh a little bit over cranking and now we're ready to test what we just did is pre-loading it and then we just take our lever depress it a little bit get it over and let it go we don't slam it over because it can reset the whole mess and then we see that the needle moved away now we have the needle moved now to some point and now we go back to the lever and depress the lever and re-latch it press it down move it over so this came out at about 69 rockwell c the black numbers out here are the hardness in oracle c direct reading and 69 sound about right for a high speed steel blank on a good day this should repeat quite well so let's do another one the problem is when it does not repeat then there is something weird then usually your part is not resting very nicely on the table or you have dirt somewhere but this is pretty much 69 again a little bit maybe half a point rockwell c under 69. so pretty decent repeatability and you saw me turning the sleeve down a little bit that presses onto the the workpiece this stabilizes everything a little bit more at least that's what's stated in the manual of the machine so that's the that's the general use of a of a wallpad voiper hardness c tester there is not too much to it the problem or the the difficulty with it is as this is reading two microns per per line a single piece of dust on here will already alter your results or you have hardened parts with scaling on them the scaling will also mess with the hardness test because it settles under load or it will crumble or make your part tilt a little bit also regarding on tilting with this table you can only test parallel pieces uh you cannot test on a sloped surface there is a probability to a crack or or break the diamond and that's the least thing you want to do why don't we just hardness test some things this is a parallel from a imported parallel set these served me very well error hard but not crazy hard if i had have have them write in [Music] in mind keep in mind that the diamond leaves a indentation so consider if you want a small dent in your part or not personally i don't care too much on my import tooling so we add the sleeve preload it back to zero and drop the diamond drop the weight stack that pushes the diamond in and by the speed this moves these are not very hard so we have to wait a few seconds until the needle settles and then we can lift the weight stack and get you our direct reading and this is surprisingly hard this parallel is 59 rockwell c which is for a parallel sting horn and before i put it back i'm going to clean up the indentation from the diamond next i have a import 20 40 80 block which is basically a metric one two three block um arc euro trade in the uk sells these these have some some damaging so you have to be careful with the stoning we put the diamond indentation right in the center because we can preload it the sleeve and there we go this is definitely way softer this is very soft so let's get our reading so this is 25 rockwell seeds so these are basically that soft let's get a file because i i oh oops yeah they are indeed very soft okay um so 20 40 80 blocks from arc eurotrade very soft so this is a more setup block this should be hard at least i expected and yes i know that this is awful to watch now because it's a pristine setup block but this is for the internet there we go let's see if this is also 25 rockwell c so we got our loading we wait a few seconds to have it settle and let's get our reading okay this is different this is 63 rockwell c that's a significant difference and yeah don't scream at me it's my tooling and i want to know this tiny point up here is what the diamond left in the part so i'm not too crazy about damaging my tool and i stoned all the the material that gets thrown up around the diamond indication away this is a soviet gear cutter a module color module one number eight gear cutter so let's see what our russian friends did let's see to be honest i was all day already testing hardness of different things just to learn about the hardness of things well i can tell you right away because i tested it this life is hard so that's the that's the soviet gear cutter i expect it to be fairly hard and indeed oh it's still moving it's still creeping so that's 65 and a half for the soviet gear cutter and somebody told me that these gear cutters i have are one of the lower grades the soviet industry produced so but i know they work i have both a a chester man play a steel rule sheffield england i think this is supposed to be hardened and also a sta a blade from a steroid combination square this is definitely hardened as it says on here so we're going to test both first the british one this is fairly thin i'm not entirely sure if i get a correct reading on this but we'll see well i can't say if i get a correct reading i can say if i get a plausible reading oh this is soft oh yeah this is 40 44 44 and a half rockwell c for the british one not crazy hard also this isn't bananas a very kind viewer sent me this because i didn't have a scale in banana so we cleaned the diamond indentation up and we checked the backside if we get a now we don't get any push through on the backside from the diamond so i guess this is still good enough thickness to test the hardness so let's go for the sterite which is i hate the scaling i hate the division lines on the steret uh combination square blade i hate this the the two double lines in the center is just awful for metric reading yeah we're dressing without the sleeve but no this is not hard this is 44 rockwell c and i will test again just because people will tell me that i'm biased because it's american tooling um i'm not but i'm not impressed by steroid tooling at all well the steroids combination square is a nice tool but they forgot to deburr it it's razor sharp and the steel they use is prone to rusting like nothing else i have in my shop so yeah still 44 and a half it's both of these scales are about soft so let's clean this indentation and i expected these to be way harder to be honest i expected them to be like 54 rockwell c this is like a pre-hardened tool steel two lux 44 that's the same hardness and you can file that stuff i have the inner ring of a shot magneto bearing this is out of a drill press spindle but they use used to use magneto bearings before angular contact bearings got widespread use so drop this in and let's see how hard this inner race is or in fact both races should be the same hardness i should be stinking hard so we stop here at around 20 and now we get our reading so we get exactly 63 rockwell c which sounds about right uh this is a shock made parallel out of o2 tool steel with a very very low temper means they are like glass yeah there's a 65 and a half rockwell c that's my own parallels uh that's a decent hardness did you ever wonder how you test your hardness test of your accuracy probably not but i'm glad you asked we have a box of these of course these are hardness testing samples they are certified and they have the actual hardness value etched onto them this box ranges from 63.4 down to 31.3 on the rockwell c scale there is also one rockwell a 81.1 but i don't have the testing diamond for this one so you're not supposed to regrind them if they are used you're not supposed to use the back side just front side and you have to keep a certain distance a few millimeters between each indentation otherwise the metal that's getting yeah gets moved around by the diamond might interfere with the hardness on the next testing work hardening basically so you take these and you just take a reading off them now make sure they are clean i know this backside is stoned because i recently used it already make sure it seats nicely find a nice spot on there that's a lovely spot here get our get our diamond preloaded whoop get our sleeve located okay and then we drop the weight stack and get our direct reading oh yeah 60 61 62 63 and some change so i'm calling this 63.5 and as i said this plate is 63.4 so yeah this is a very powerful tool and with the calibration plates it's very it's it's easy to prove it out yourself if you don't have the sample hardness plate [Music] you are a little bit in a pickle you can find a friend that has a hardness tester too and take a high speed steel blank to him and hope that the steel is good quality and very homogeneous all around hardness test it engrave the hardness you measured at your friend's place with his calibrated harness tester and then take a reading with your own uncalibrated hardness tester at home that would be an alternative or you break down and buy the hardness testing blades they are expensive one of these costs 300 euros one of these there by the way the new and improved triangle format that's not a joke that's actually what the paperwork said i was thinking we could do also a vikka's hardness test because it's a little bit more complicated than just reading off the dial indicator for that first we need to exchange the diamond from a conical diamond to a pyramid shaped with a tip angle of 138 degree so we take the diamond out and here is the other diamond for vickers hardness goes in make sure it's seated up here all the way and we can just leave the leaf away for now and i was thinking we could use a reference plate from my hrc samples this is a 61.7 rockwell c sample plate and we will use this we will determine the vector's hardness and compare it to the rockwell hardness so we see if we get a reasonable result that way since we're doing wicca's hotness testing we can select any any weight we want the thinner the material the less force you want on very thin pieces there is a small force range for biggest hardness that goes up to i think one newton and there's even a micro range for because hardness that is even lower and you use that to check the hardness on [Music] for example nitrided parts case hardened parts where you do not want to poke through the hardened case you want to know the hardness off the case or the nitride layer let's let's go for 100 kilograms which is not entirely true if i select 100 here because this machine is basically set up for rockwell c testing that's 90 kilograms of testing force plus 10 kilograms of preload that's the that's what i did with the hand wheel earlier when i moved the indicator two and a half turns so this is basically 981 newtons because 100 kilograms times 9.81 meters second square minus 98 newtons which is 10 kilograms is our actual force that we're going to use i will do that on paper later it's a little bit confusing but we're running with a 100 kilogram setting here on the machine we just need to take care of it on when we do the math and we find a nice clean spot on our sample plate crank our table up first i want to to mark an area i drew a little square so i can identify my indentation later and we bring the diamond in contact and we release the weight you don't see much now the indicator is not moving and we're just waiting about 20 seconds for the diamond to settle it's like six seconds off time with the force applied slowly and then 20 seconds off waiting until it settles out [Music] so this is boring as can be but you get the idea let's unload it and get our sample out there we go there is our wiggles hardness test of this plate inside this blue square kind of square all the other dots are rockwell c tests so let's go to the microscope we're over at the microscope and you're looking through the eyepiece which i'm not and here's our test plate and you can see those circular indentations those are from rockwell c testing and if we search now there's our square and here is our pyramid indentation and now we measure the diagonal size of this of this indentation we orient it correctly a little bit hard to do this through the viewfinder of the dslr so we start here zero out the the dial on our tool makers microscope and then we move over measuring the the diagonal of this indentation like this this is about right so this is point four six millimeters point four six and we also measure the second a dimension from here because we're building the average of those two measurements so we start here zero and this is 0.44 0.44 so yeah that's how you measure the size of the indentation for weakest hardness testing off to the paper the size of our indentation let's draw it from a top down view like this was point four four and 0.46 so the average between those two is that's d equals 0.45 you calculate that by adding those two up and dividing by two here's the formula for wicker's hardness testing in our trusty tabenburg methyl and we have wicca's hardness is h3 equals 0.1891 multiplied by the force divided by the square of our diagonals so let's write this down h v equals zero point one eight nine one multiplied by f d square equals zero 0.1891 multiplied by i set the machine to 100 kilograms 100 kilogram multiplied by 9.81 meters per second square equals um [Music] 981 newtons that's with the 98 newtons of pre-force minus 98 newtons preload we don't want that we didn't do the preloading in this case so equals 883 newtons now there's a little buff a little bit of rounding error in there but me this is this is good enough so we have 883 newtons 883 newtons divided by 0.45 millimeters square equals 0.189 [Music] 1 multiplied by 883 divided by 0.45 square equals eight hundred and uh wiggles hardness of eight hundred and twenty four so we have a wiggles hardness of eight hundred and twenty four so 824 hv and since and normally you write the force that you used for your wicca's hardness behind it in kilo pounds not kilo kilogram kilo pound is one to one because kilo pound is basically kilogram force um so but we have we we took away the 10 kilo pounds of preload so it's hv 19 because hardness 90. um and this compares if we take our trusty table here so we have a wicker's hardness of um between 800 and 840 and we have a rockwool hardness that's oc association associated with it between 64 and 65 so basically 64 and a half and the test plate 61.7 hrc so we are 2.8 [Music] hr c off that's less than five per percent of the of this less than [Music] five percent so yeah this is this is the weakest hardness about the weakest hardness of this plate compared to the real hrc hardness so the measured because hardness goes to 64.5 and the real one is 61.7 so we have 2.8 hrc off points of hrc and that's less than 5 percent so that that's the idea behind because hardness and when we go back here in the book there is a minimum thickness of the material in relationship to the material to the force you're using on hv100 which is a little bit more than we did now like 10 kilograms or 100 units more the minimum thickness ranges from about 0.8 to 2.5 millimeters otherwise your reading will be off but you can also go very thin with 0.2 kilograms of force which my hardness test cannot do you can go down to a sample on higher hardnesses down to 25 microns starting at 100 micron so pretty pretty universal way of testing and uh because hardness is always comparable you can compare a vector a heart a vicus hardness that's tested with 90 kilo pounds will compare one to one to one that is done with 0.2 kilogram force so it's very universal and you can use it for a lot of things and with the microscope it's relatively easy to measure these dimensions so that was a little scores into wicca's hardness and rockwell hardness testing of course i hope you enjoyed this thank you all for watching and i'll be back long time viewers of this channel might remember these these are hardness testing files made by subosan the japanese company and these are used as an average tool to check hardness you have the manual up here and they're quite self-explanatory they are incremented in five hrc 40 45 50 55 60 and 65 and you just go through the files against your work piece or the part you want to check and once you reach the file that doesn't skid over the surface anymore you you know about the hardness of the part you have a chart up here if the hrc40 file touches the work your part is about 40 to 42 rockwell c if the 60 hrc file hits it 60 to 62 and so on it's just easy way to compare and over here are the hardness wickers values and they're to be applied like this on a flat surface like this like this and a bore with the internal band of the of the file so let's compare this against the wall part out of i remember these because i cross checked them with the hardness tester at work to be fairly accurate if if used with caution this is a shop made parallel out of o2 tool steel and 40 rockwell c file doesn't do a scratch 45. this gets right over it 50. nope 55. nope 60. now we're getting into some nope and we have a 65 hrc file and this barely scratches it not really so we are probably above 65 rockwell c uh let's go to the hardness tester and check this part so let's check the parallel diamond is exposed no no burrs on the part and pre-loaded whoop 150 kilogram and here we go so here and measure it 64 rockwell c this is this is the upper limit what what 02 still can get to and also that's the upper limit what the hardness testing files can check so this is a better example than the parallel that we used before because this is a little bit softer in my if i remember correctly so again we go through the file starting at 40 rock we'll see this just gets over it 45 rockwell c skids 50. let's get over it 55 nope nothing skids over it and the 60. yeah this wants to bite it definitely wants to bite into the material and i'm scratching all my my v block up here so 60 65 yeah this definitely bites this definitely takes a cut a very small cut because it's between 60 and 65 rockwell c part in preload it preload it till the needle stops moving and release the weights okay settles out wait a few seconds and see what we get that's 57 57 rockwell c with the hardness files i got to about 62 rockwell c so we are about five points hardness points off which is still not terrible especially considering the price of the harness testing files which is about 70 euros so in case you're curious this is a very good way to secure a wallpaper hardness tested to a trailer you bolt it down to a pallet you bolt the pallet down to the deck of your trailer you use an additional strap around it and you strap the whole top of the hardness tester again down to the trailer and that's a very safe way to transport this thing also you have to immobilize the weight stack and back for example by stuffing in some rags also it's a good idea to remove or disengage the linkage on the internals unloading is easy with a with a strap around the neck of the hardness tester using a ratchet hoist removing the pallet and then you can just put it on a small trolley i have to thank my friend tom and his father again for horse trading this hardness tester it's really a nice piece and it will get used in my shop for sure and i hope you enjoyed this video about the hardness tester about the theory behind it and some construction that has of this machine thank you all for watching thanks for the ongoing support and i'll be back you

Channel: Stefan Gotteswinter

Views: 23,686

Rating: 4.9559674 out of 5

Keywords: Wolpert, Härtetester, hardness tester, rockwell, vickers, boschprofil, aluminium extrusion, microscope, toolmakers microscope, hardness testing, hardness testign files, härteprüffeilen

Id: U6SmsX44noo

Length: 54min 5sec (3245 seconds)

Published: Sun Aug 22 2021