Shopmade parallels - Part 2

and if you wander such small pieces that are hard to be sawn on the horizontal bandsaw I cut them up on a milling machine with a slitting stall looks quite good there we go just cut up the piece into strips now we can deeper them and mill them rough to size and then we're going to harm okay I'm a little hardening set up here I have my little fqo 1:10 pottery oven that goes up to 1,000 degree C something like that my multimeter with temperature probe and we are now at 634 degrees C but we need to go on a bit further for hardening okay what I have here is the datasheet for the steel we're using it's 128 4290 manganese chromium 8 and when we get heat treatment hardening temperature 782 820 degrees C and quenching in oil or hot bath the hot bath is sophisticated stuff we can't do that at home but we can do an oil quench and down here is the the chart for tempering or annealing I think it's the right term for it to get it to the desired hardness we will not temper it with a leaf it at about 63 Rockwell C so that's work we are going to do we're going to heat the steel up to 800 degree C maybe 820 because by the time we need to take the steel all of the awl and drop it into the oil it will be cooled down to 800 degrees C and then we will straight nut apart and Hart mill or write them and this is one of these small ovens with key the last window in front and the insulation on the door is non-existing so I take a fire break place in front of the door this helps speed up the heat the temperature rise really significant ok we are at age twenty degrees first one one I've put the aluminum Ron stuck on top of the after oil container to keep the smoke down until it settles often with unplug this will cool down and I will have a break okay I haven't I hardened to paralyze I'm going to take a file its gates rice glasses these are now about sixty Ruggles heart so next step is to straighten them out because won't take a straight edge and we look yeah that didn't work much but I hope you can see that there is a light gap on the left side of the straight edge again zoomed in you can see that parallels not straight anymore what we're going to do is we are going to pin them and what we need for that is a heavy object piece of steel is just faced off on one side on the lathe and a hammer a pin hammer across peen hammer and the way I like to do is I take my I take the steel on my leg then you look again at your piece and the site that is hollow goes up side means so now it's this way the bow is down on the plate now you just take your cross peen hammer and work the surface I don't do this on that lever parent because it's awful loud my leg has enough math to them Matt and yes I'm hitting a hardened piece of steel with a hardened hammer and for that reason and then you check continually how your part is and I went a bit for now it's bent in the other door when we take a look through the straightedge you don't see much of a light gap anymore practically it's straight so that's the process of straightening a thin hear it apart and at the part is about sixty Rockwell's hardly don't get much of a it don't get much of an imprint from the hammering normally our runs at work do it - they have carbide faced hammers they take a hammer they mill in a slot and then they braise in a piece of carbide works better than a steel hammer but of course the carbide really leaves dimples in the surface but when they do it they use it to grind to straighten out punctures and stuff that scaling that gets round all over and then the dimples from the hammering get grind ground out but it's a neat way to straighten stuff that's straightening by teaming just with a hammer there was also heat strip straightening for warped parts my dad used to do it went back in the day when he was a tool die maker they straighten parts after hardening with the flame but yeah I can do it a long time and he did it and at work we don't do it also and also yeah the hammering is easier another way is of course to grind the bow out but with such a long and thin piece it's hard grandbo out you would have to shim it in the center on the magnet and then grind it flat flip it around around and it will warp again when you grind it too hot and all sorts of problems so thousand ways to skin a cat okay I set the hardened parallels up on milling machine again same setup as before a white parallel down there to span the t-slot and a narrow parallel to give me clearance for my cutter and then the two parallels in pair clamped down with two strap clamps for flu carbide end mill same as before this one is suitable for milling so shouldn't be a problem to get through this material running at cells nor PM's dry and yeah I took off the the middle scale the scaling from hardening before like timed everything down because yeah because and when hard milling you want to keep your depth of cut pretty low you cannot take a 1 millimeter deep katana on a machine like this in hardened material won't work when you do hard milling you want to do more than one spring pass otherwise you will end up with a with a with a CH that's with a side surface that's not Square to your setup because the color gets deflected okay first aside bond took to spring passes and you didn't get any chips after the last spring pass nice clean surface and it looks good surprisingly the surface finish when you do Harley milling it's always pretty good if you get a bad finish on hard milling your cutter will break very soon so that's the reason why you don't see a lot of bad finish on hard milling there we go now we can take Ted on the setup and give it a matter on the surface point okay i clamp the to hard meal two parallels against bigger parallel because these are sending up quite high and what's getting a bit tippy and measuring was quite complicated so let's start again here in the center this is again number one number two zero we go over to the left i have minus two and we go over to the extreme right and we have minus four back to zero now we change over to the stack in parallel okay we have zero in the center - for extreme left and - to extreme right so these hard milled parallels are actually better and those that we machined in soft state that has nothing to do miss with soft and hard maybe it was because I was taking more spring passes on this or Moon and Mars we're in the right constellation to each other look who knows milling to closer than one hundreds of millimeters bit as a teracle so I'm quite happy with that result and when you look we have minus 4 here and minus 4 here - - here here these got flipped over in the process they are exactly the same just flipped over so that's a one way to make hardened parallels if you don't have a surface grinder in your shop you can't of course also lap them you can harden them and then you start with Emery cloth on the surface plate then you go to wet wet paper wet grinding paper with some oil let them check them measure them go back to lap and then you can lap them with slow can carbide grids on ie on a cast iron plate to give them to make them as accurate as you want you can make them gauge block accurate if you want without a grinding machine takes of course hell of a time so even if you don't have a surface grinder hardened parallel or not out of reach and this is of course the easiest way to make precise parallels the surface grinder I have to to harden parallels between let's let's take the setup apart after two hardened parallels up against a bigger parallel so they don't fall over I have a ground block in front of the parallels to block them in so they don't go that way and I block them in with another parallel from this side and that's plenty of holding power for this light grinding operation okay we dusted off the first side you can see I have a 60 grit wheel on there and we got a pretty good finish still having balancing issues because I don't balance the right now take off everything clean off the magnet and you do surface grinding cleanliness is everything now take your parallels clean them also be careful surface grinding produces a razor sharp Brook had edges on the work pieces okay get everything contact with the magnets there we go these should be well within two thousandth of a millimeter now take them out and check them on the surface plating let's check the ground one I change the setup on a surface plate because moving the surface gauge was not reliable anymore for this grade of precision I'm pushing the parallel under the dial test indicator along zero hour dial and tap the stem of the height gauge lightly so everything settles down zero in the center zero now we move over stream left that's plus one maybe plus one we go over to the extreme left right and we have plus plus two so it makes a slight bow in the center and I even know why this is the case when I ground the second side I took a quite heavy cut you might have seen this in the and the footage after grinding and I think what happened is that part expanded grinding will took a heavier cut and now as it settled down and went back to room temperature we have this nice bow in it let's check the other one if it's if it's as bad push this one up sure it's clean okay but this is the second parallel we start in the center at plus one we move over to left we have zero and we have plus plus one so these are as I said before what within to thousands of them if I had taken a bit more care when grinding these would even be better but parallels to thousands of millimeter for the milling machine good enough so these are the parallels that we just made by grinding they started us as the hard milled ones and then I went up a notch and ground among surface grinder now they are well worth the time and effort the smaller ones that we made in the soft state I hardened the mouse I now grind them too and then I also go into the set of parallels and over time I hope to build up a nice collection I shot me pearl s that I can use or machining operations I hope it was interesting to see different approaches to get to parallels that are absolutely good enough for shop use even if you don't have a surface grinder like by just using cold rolled steel cutting it down and using the Taylor parallel so I hope that was something in this video for everyone thank you all for watching and see you next time

Channel: Stefan Gotteswinter

Views: 33,617

Rating: 4.9966187 out of 5

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Id: 5QE-1S-3HQY

Length: 19min 36sec (1176 seconds)

Published: Sun Jul 24 2016