Mounting and Grinding a Surface Grinder Magnetic Chuck
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- čas přidán 11. 05. 2017
- In order to get my Landis 3S Surface Grinder going, I needed to grind and mount the magnetic chuck for it. In this video, we will go through the process I used to both check how flat my original grind was on the surface grinder table as well as how I ground and mounted the chuck.
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it amases me that adults have time to nit-pick about woodgrain instead of taking in the bigger picture and enjoying the development of Keith's workshop.
Keith I've learned a lot from you. Keep on the good work
Nice to see another machine up and running in your shop, the whole shop is coming together nicely.
Excellent job bringing the old machine back into operation. Taken care of, It will outlast us all.
Fascinating! I have learned a lot about surface grinders from this series.
Excellent lesson on Hydroplaning!! First thing that came to my mind watching that BesTest!
Hi Keith, been watching you for some time now since way before the new building, and you've come such a long way in building your new shop, its really looking great - so much hard work and so much help from viewers, that's amazing to see in this day and age. Love seeing old machinery some consider outdated and used up be brought back to life and put back to work where it belongs. Best wishes on future projects, cant wait for those videos too--lol
Really enjoyed that, thanks man! Educational, this answered a few questions that have entered my mind on occasions. Can't wait to see this bad boy in action! 👍
That's one nice machine, good job Keith.
Lever actuated magnet = "permanent magnet". Very nice grinding.
That has me inspired I have vintage surface grinder ( no hydraulics ) sitting on a pallet in my shed, I keep sending jobs out to be done, think it might be time to put it on solid ground a start using it
I learned a lot by watching this video! Thanks so much for posting this. Bob Troxell, Virginia
Great video Keith, I am ready to tackle my machine now.
Keath, what you have is hydraulic ramping that takes up bearing surface. (It is a little bit like hydroplaning). Compounded with the teeter todder effect, you ground the table with a slight convex. To amplify this even further you ground the magnet both sides. When finished you will see it ground the magnet convex on both sides(or slightly thicker in the middle of the magnet). Usually the magnet back would be ground on a larger surface grinder. Since you're doing it in house, the way you've done it, is probably the same way I would've.
I think the previous owner of my grinder did the same thing. It goes up three thou on the left side and up six on the right side
I was a tool grinder for The Timken Company for 22 years and we almost always flooded coolant when grinding to control heat.
THANK YOU...for sharing.
wwll keith, thanks for continuing to post the progress on this, if you can maybe see what mr. king thinks, he might be able to steer you in the right direction to keep that table parrallel when switching directions.
and please do not take this as trolling, watching what you are going through, is preparation for me when i get a grinder in my shop.
We had a factory rep give a demo on how to dress a chuck , and he recommended dressing a hollow in the wheel and using Crisco as a coolant . Always worked well for me.
Thank you so much for making this video! Helps me a lot!
I'm not liking how many people comment without watching the whole video.... He warmed it up each grind. Come on people if it's not shown or said (and he mentioned warming it up each grind) give him a sandwich here. I don't want to hear him say he warmed cleaned and lubed up the machinery every time he does a video. edit: not that I don't like hearing Keith talk but life is short.
AMEN!
Funnily enough, Keith’s voice is the last one I hear before going to sleep at night. Very soothing. 😂😂
Why not check for flat using your surface plate since you have one? The indicator attached to the head is not really a valid method to check for flat since the machine produced that surface it should always follow it, but it could be running like a roller coaster and never show it by that method. Could you alter the oil system to the ways so it runs off the pump? On my Thompson it uses constant oil pressure feed to the table and I don't ever get any indication that it is floating.
thought the same!
no the way he did it was correct. When the chuck is ground it negates everything such as oil. When he runs the indicator along that trumps everything else.
@@jaysilverheals4445 That method proves parrallel but does not prove flat. I have seen many grinders that would indicate the chuck flat but made parts that were ground thin in the middle because the grinder ways are worn in the middle.
its all coming together keith surface grinder is coming along nice
Thanks for the video Keith
I think you have a very great surface grinder. Good fine Keith.
Keith, I think you want an AC field to demagnetize a part. For example, to degauss an old (very old) color TV tube shadow mask, you'd turn on the AC degausser coil then move it very slowly away from the tube a couple feet before turning it off. Very interesting video, as always. Thanks! Jon
Love the beared Keith. Hope the wife loves it too
Really enjoyed the video 👍
Never heard of a grinder using an electro-magnet chuck. Pretty cool.
Looks great to me Keith , Thumbs up man ! Good job man..
Hello Keith good job grinding the chuck plate
Looks like fun, I used to enjoy running surface grinders.......🍁
That was probably a vacuum tube power supply in the electrical cabinet. I replaced one(vacuum tube- 5U4) back in the mid 70s on a much older grinder with a solid state version of the tube.
...Yeah, a friend of mine had a very old Jig-Bore machine....used vacuum tube supply for the DC spindle motor.....
Man, that is cooler than moose lips! Great video, Keith. Happy Mother's Day to your wife.
Rich
If nothing else, your new electric supply for the magnetic chuck definitely made things simpler, and that should reduce problems on its own. I agree, its much better the way you've got it, maybe something else works better when its installed in a factory somewhere, but there it has both voltages easily connected to it.
Great machin Keith ;)
I saw Waynesboro, PA on the side of your machine, and thought that sounded familiar. I was recently reading about Emmert vises. I believe that town is stamped on your patternmaker's vise, as well.
Hi Keith. I noticed something when you were talking about reversing the direct current to demagnetize the chuck. I worked on rotary grinders that ground brake pads on a pedestal with 8 stations,using direct current to magnetize and demagnetize.Underneath the pedestal for each station were 2 microswitches.One ran on a cam that magnetized each pedestal while it was under the diamond grinding wheel.The other switch contacted a very short cam as the part left the grinding wheel to demagnetize that particular magnet so,a servo arm could remove it.If the demagnetize switch was stuck on, it would demagnetize and,then,magnetize in the opposite direction.Sorry for making a short story long but,what I am trying to relate is,when you move the drum switch to demagnetize,don’t hold it there or, it will magnetize it again.What would be much better is a switch to turn the magnet on and a momentary contact push button switch to demagnetize by pushing it for a second or less.Sorry for the long explanation.Great video. I have gone over many of them,several times.
Keith, I noticed the new power cord for the mag chuck is dragging across the back of the machine. It won't take long to wear through the insulation if you don't clamp it down.
outstanding.
Nice job Keith. That will be a very useful machine. Glad you got rid of that old rectifier and the dodgy cable. Best wishes.
superb!
Hi Keith,
Are you going to hook up a coolant system on the grinder? If so what type of coolant would you use, oil or synthetic? Every time I used synthetic it would crud up the bottom of the mag chuck in less than a year, never had the problem with oil base coolant.
I was wondering if the .0008 showed up with the chuck on the table, and if the " fall " from the hydrostatic showed up with the chuck on too ?
Thanks in advance. Love the video.
You can see the wave pattern the grinder left on the bottom of the chuck. When he stoned it, you could here it too. I haven’t gotten to the end of the video yet. It will be interesting to see what happens to the top. If he’s right about the oil, then that’s a major reason those waves appeared. There is harmonic vibration from the wheel and the chuck that isn’t being completely damped by the mass of the machine
I had always thought with the indicator probe at that sharp of an offset angle causes a cosine error on the probe?
From 8:24, that is some lovely in focus shots of the wood grain of your ply walls. Loverly walls!
Shame we can't see the machine.. **runs and hides** :)
the silly autofocus combined with the small monitor screen, he uses a very nice camera, but still autofocus issues happen, i kinda of like the gopro way, as its fixed focus, one less thing to worry about, such as abom uses
Keith does such a good job normally that the rare times he messes up it's really obvious, hopefully he won't take a little teasing as anything but the fun it's intended to be.
And the strong grain on the wall DOES show up super clearly, likely why the camera grabbed it for focus instead of the 'soft' machine.
Great to see the machine get some use! Quick question; do you oil the chuck surface when you're done grinding it...the spindle oil again?
I wonder if you ought to allow the machine to warm up, or more the point the oil in it, before using it. I suppose in south Georgia it might not matter in the summer but it might in the winter!
Nice machine. You need to replace that mag indicator light bulb with a red one. Less glare. Thanks for the video.
Interesting how the oil film caused that error- for others looking to do the same job, perhaps the solution would be to pile some weight onto the ends of the table during the original grind to flatten that film out.
Hey Kieth, I've been meaning to ask you... any regrets on your pittsburg engine hoist? I'm in the market for one. Thanks, Will in everett wa.
Keith, great video as usual. I really liked how you pointed out the thickness of the oil changing the indicator height.
Does this grinder have provisions to wet grind?
Keith,, I'm rebuilding a B&S #5 surface grinder 8×24
Serial #963 30s 40s ( know anything about this one)
Keith, I have been following you CZcams Channel for a while now. I am new to machining (hobbyist) and am adding equipment to my shop. I am trying to lean more about the surface grinder. Do you have any info about the Make/Model of your machine?
I am very familiar with rectifying AC to DC. Is there a filtering device in it to change it from intermittent DC to DC? Just wondering; I don't think it would matter that much but just for my own info. Wow, the oil does make a difference but that shouldn't surprise me as we leave clearance for lube in most bearings. Thanks Keith and looking forward to the lead screw job. Greg
I wonder if there is any runout depth wise. Seems to me that the grinding wheel would wear a bit for each pass. Also, there looks like you have some back EMF from when you switch off the magnet (because it is an inductor I guess). Probably not going to be a problem, but maybe the lamp or the rectifier might burn out prematurely(?). And lastly, a big thanks!!!
Pardon me if you've mentioned this in the past, do you plan on doing a full restoration on this grinder in the future?
Great video! One question though... Did you use an isolation transformer for your chuck wiring or are you directly rectifying wall current? Directly rectifying wall current is very dangerous. If you don't have a transformer before the diode bridge you really should add one. They're cheap and could save your life. Also make sure you've properly grounded the metal chassis of the chuck to the ground lug of the outlet. You should also install a suitable fuse between the mains and the isolation transformer.
Nice video , could you explain a little about you grinding wheel choice ? what grit and hardness would you use to grind the chuck ? does heat build up and affect the grind?
Yes heat buildup is a problem. When you dust the chuck you are doing the hardest operation you can on your machine. You are grinding to its max capacity. Ie highest heat buildup.
There are many ways to do it.
The way I do it, on my mitsui ball way grinder is.
New 7" 46 grit j wheel. Usually a sg (Norton ceramic or gell wheel as it's what we have. But they are not conducive to light cuts. They like heavy so that they can shatter and expose new grains vs a conventional wheel)
Dress open structure with a cluster diamond (not a multi point but a cluster. Think of a diamond file but on a cylinder. With more thickness)
I run my speed reducer (ac frequency inverter) at half speed, so about 1800 rpm on my grinder.
Light oil film of wd 40.
Quick to fast table Traverse with .025 step over. Max downfeed of .0002
Max cut between wheel dusting of .0004 but once the whole chuck makes contact. A couple of passes at .0002 and then a finish at .0001 with a dress between each.
Doing this, minding my carbide dust (it's about all I grind) I can keep my chuck flat to .00015 for 3 to 4 months.
At 6 to 8 months I have to take a whole .001 off to clean it up.
Sorry if that's too much info, that's how I dust my chuck.
Some day I'll try different wheels, but I don't want to so that with my work grinder. I'll get myself a grinder one day....
Hi Keith, pardon my ignorance but grinding a largish part like that Mag chuck does the grinding wheel get smaller as it traverses the work piece therefore creating a minute taper. As I understand it, as it grinds metal away it must also wear away the diameter wheel at the same time, albeit only in thousandths of an inch, do you do anything to allow for this?
Maybe a squirt of silicone spray might help with the indicator pin loading?
Good call to replace the rectifier. Before solid-state diodes, rectifier technology was quite cumbersome and often contained hazardous materials like mercury or selenium.
although selenium plate rectifiers go back over 50 years, even they have their fragility, before then it was things like rectifier valves or mercury arc. basically modern rectifiers are superior in every way compared to the old ones, and a no brainer to replace
That or you built a motor-generator to mechanically convert your AC to DC and while that did away with needing mercury or selenium, now you had more moving parts, another shaft to keep lubricated, and in the case of this machine, likely a third motor to power. So yes, modern solid-state rectifier still a far better option.
how does the grinder compensate for wheel wear?
what type,grit etc wheel are you using?
Seems like you would use bluing and a straight edge to check the flatness of the table, since the table is probably too large and cumbersome to try and put it on a surface plate? What is the spec on the ruby colored wheel you are using? Manufacturer, grit, grade etc. Thanks for making the video.
Keith, just out of curiosity, how was the original power supply box wired for the magnetic chuck? Just 110 V/1ph in like it is now?
kinda a shame it had a few dings in it but there's plenty of table there that's plenty flat now you need a giant diamond hone for trueing some humangus stoning stones. I'd test grind something and make sure that oil wedge settles out with the pressure, leading edge thinner . just awesome size on that chuck. good to be busy thanks again
Could you please drop a link for the Rectifier used for that set up please
If the second Switch position is for Demag it might be a good idea the have the Indicator Light off for obvious reasons
So with the mag upside down and the mag on are you warping your mag or the machine?
how much can you grind on the magnetic plate before it is destroyed?
keith, make a point aboutwherethe diamond should be when dressing the wheel.
Good to see the old girl ready for work again.
Hi Keith,
Are you planning to get some kind of a cooling system on your grinder, cause with my experiences I don't see how you'll make precise parts without it, even so much more with thin parts...
The slightest amount of heat acts on the metal parts surprisingly more than we could imagine even in parts as big as your chuck...
would the chuck itself get hot from the electricity resistance too? one of them cool mist might be an easy way to go?
4:35 - For those who don't know, half a thou is 5 tenths... so error is between 5 - 7 tenths. 17:45 - As it traverses and switches the direction, there seems to be a great deal of vibration for the auto traverse, wouldn't this vibration nuisance be added to the surface finish?
Is it just me(and I have very little experience with grinders) or the mag chuck should be mounted with that electric box on the back(facing the spindle???. I might be wrong(probably am)
Please excuse my um, inexperience in this.
But would this machine do what your scrapping would do, aka make a part close to as flat as possible?
Ooo, was the old rectifier a mercury rectifier???
the only thing the older electronics for the chuck would have done is give you the ability to adjust the amount of pull your magnet has. John Saunders has a video on how that feature is used when he ground his parallels.
Cool video Keith! I am starting a CZcams channel, any good advise for a newbie? I've been enjoying your videos for a long time as well as your vintage machinery website!
Advice
So many expert thumb downers without a you tube channel
I’m late to the party but the machine seems loud. I worked in a tool and die machine shop that had 4surface grinders that ran from 7AM to 11 PM and combined they made less noise than that one. As well… if we ever turned the grinder off, we warmed the machine up, dressed the wheel and then started grinding. Is you restart the machine dress the wheel every time. The only times the grinders were turned off was either end of shift or to change the wheel.
do you need thinner oil?, when it gets cold your issues could get a lot worse, i suggested it was the facing wave of oil in the last vid, we could see the leading edge always getting more grind
I noticed that too. On the plus side, the cut reduces when it settles but does mean careful final measurements will be needed due to the uncertainty.
Jusb1066 Agreed - may be the gibs need a bit more adjustment as it looks like the table is lifting at alternate ends each time the direction of travel changes. Check it out at around 17:30
yes steve, it does indeed seem to show both the leading edge floating up and it dissipating over a second or so, just like his dial gauge did
My grinder is functionally the same as Keith's. No gibs. The table is only held on by gravity, lifts right off the slide ways. Yes, there is a sort of a "bow wave" thing going on, and I see the same action on my surface grinder. It is no doubt caused by the oil on the ways. It also seems to change some with time elapsed since oiling on my manually oiled machine. Tells me when to oil it again... As a surface grinding newbie, I am still trying to learn and make my peace with the machine. Working to the higher level of accuracy that some work requires is a whole new learning experience. Getting a good surface finish on different work is often a lesson in humility.
Another possible issue with the sparks pattern on Keith's grinder might be the electromagnetic chuck warming up and warping. I am using a permanent magnet chuck, but I also get the same issues Keith was having in the video. I think it is mostly the oil on the ways causing the issue.
How many times can you redress a magnetic chuck? Is there a limit to where it will no longer work? I have a chuck that has a gouge taken out of it. Probably .005 deep.
Why are there screws on the table and why are they are not countersunk more? Sorry for that beginner question. But I am not sure I have ever seen screw heads on a machine table before. Thanks for your videos Keith! Love your work and the chuck looks amazing now!
The screws were in the wooden pattern used for casting the table. There are no screws in the center of the table, only the imprints of them in the casting sand, and then in the cast iron.
Ah that makes sense! Thank you for that information!
Great... except just rectifying 120 VAC for the chuck. If the chuck is truly rated to run on 120 VDC nominal, full wave rectification of 120VAC will actually feed about 168 VDC to the chuck. This about 40% higher than the 120 VDC rating. While the chuck may "work" okay with that, the greatest danger is that you may get some undesired heating effects on the chuck from the excess voltage. This could easily effect your grind quality. It may easily contribute to decreased life expectancy on the chuck. To solve this you could add a transformer with about 86VAC secondary winding. You could also feed it from a Variac. To determin transformer rating in Watts (volt amps), measure current your existing setup draws and times the input voltage. This would give you a bit of safe overhead for the transformer. A good US supplier for reasonably priced transformers is "Signal Transformers".
Hi Keith,
You can simply take one of your three phases and the Neutral and you have 110 V. There is nothing to it.
All these comments about 168 VDC from rectified 120 VAC are forgetting that reaching 168 VDC requires capacitive filtering. If the rectified AC goes directly to the chuck coils, average DC voltage will be lower than the peak voltage by a factor of root 2, i.e., 1.414.
pick a color -- gonna sneak in there and paint the place!! :)
Stefan probably cringed as you took that stone to the bottom of the chuck like that!
Can one grind engine heads on this machine?
I can smell the grind
Hi Keith I am no expert but i found with my surface grinder you have backlash just like any lead screw so when i dial down to much i come back up beyond what i need and the come back down Just saying
I did not know that " Earl" was that thick... lol...
Does the grinding wheel wear out (reduce its diameter)?
it does, but you cut light over the entire job so hopefully wont affect your finish, might have to redo the wheel truing from time to time
Ready to take a stab at Tom Lipton's five block challenge?
i grinded my friends mag table lately. it was ok in the beginning, i stopped machine and tried to start one more pass. Mag should be on in order to start wheel, there is a protection circuit. So i de-magged it also before stopping. Anyway this time mag lamb took a while to light. I finished the job and stopped the machine completely. Then we took a workpiece to work on, surprise mag is not going on! Waited about 10 min and light was on again. We completed the work also shot down machine to change workpiece, this time light gone totally off, it is not working still.. we are not sure if the reason low/improper voltage or circuit thing, or just because of our mag table grinding ? Cables are old and worn out a bit, where should we first look into? Very same mag table in the video, 120 V DC about 170 watt if i remember correctly. Thanks
Very interesting to see the effect of the oil film! My guess is that the pressure of the grinding wheel would not counteract that and that this machine will not produce flat parts until that is tuned out somehow. It would be interesting to see a ground test piece printed on a surface plate. Perhaps taking lots of narrow passes evens out the effect, but I expect it's grinding convex surfaces...
Hello Keith, here at Osborn we are following your channel and we really like your videos.
There are probably many Osborn products that would help you get your jobs done.
Check it out: www.osborn.com
Spark out your wheel, a few times, until it stops sparking full length.....🍁
Is that JUST a rectifier in that box, or do you have some voltage control as well? The reason I ask is that 110V AC, when rectified will produce MORE than 110V DC (possibly as high as 155V). This is because 110V AC is an RMS (~average) voltage (as the voltage is always alternating), so the actual voltage is often higher than that.
Whilst the chuck will run on 155V, it may not run for very long!
considering the size of the box, it must have a transformer, a rectifier is about the size of a postage stamp
RMS is not the same as average, the average of 110V AC would be zero (because its symetric AC).
RMS is the DC equivalent voltage that produces the same power on a resistive load as a similar DC voltage.
Just a rectifier would be fine, but if you add smoothing capacitors you would indeed increase the voltage and the magnet is likely to burn out.
EscapeMCP Technically you are correct but the power rating of a resistive load is the is the same for AC or DC (generally). There will actually be less watts into the coil using rectified DC because of the rectifiers loss. Even with a perfectly rectified AC sine wave the output DC voltage will never be very close to RMS... And that's basically why mathematically you use RMS in most circuit design not peak AC voltage like you could read on a scope. The reason for rectifying the voltage at all is like Keith said to control the magnetism in parts and even use it to your advantage. Just because you rectify a 120v AC circuit does not give you 150v DC there will still be peaks and valleys (especially under load). Granted there may have been more loss with the older circuit but it's negligible if it's rated for 120v... Great question tho really, I'm new to his channel and have some electrical background. Keep up the good work Kieth!
Guys, the problem is the coil would be hit by the filtered voltage for just an instant. But would this cause an effect over time? Greg
it is a coil. and coil resist sudden change in current so it acts as filter as well. I bet coil for such machine is made much over specs and it can handle much higher voltages and currents then 110v.
Well that's why I haven't been seeing videos. How did I get unsubbed?