Over 50 years ago I ran a Thompson grinder very much like that one, the hydraulic pump whined the same way until the boss had me rebuild the pump. The race that the vanes (Vickers vane pump) run in was worn with chatter ridges, replaced it and the vanes and the whine went away.
Back in the early 80`I ran a 20` Thompson surface grinder in a job shop. Some of the work we did was the angle plates for j c Busch. Did ones up to 4 feet tall square to 2 tens per foot.
Balancing isnt worth the time IMO... I run grinders for a living we buy pre balanced wheels from norton and they are plenty close enough no one at my work balances wheels I'm still able to get sub 8ra finishes easily. Also I think your surface finish issue with that SG wheel was dress speed... if you watch the video you dressed extremely fast with the sg wheel using hydraulics and a lot slower with the SC (silicone carbide) wheel... any of those wheels will give a good finish it's just more of how well it cuts and how much stock removal you can get done in between dress cycles... just my 2 cents...
I can hardly wait until I see my own Mississippi square!! Well done! I know now why all the old timers I knew didn't put up with anything. They were tortured at night by nerve pains. My carpal issues would wake me at night with a red hot ice pick feeling. I didn't have much tolerance during that time. Amazing how a few years will give you better perspective.
if you have carpal tunnel the diagnosis is if you shake your hand down like shaking down a thermometer. if that is the case you should get the operation like I did. any questions on the procedure I can let you know interested.
@@jaysilverheals4445 Thank you! I got mine done late 2019. Thankfully, the nerve conduction study didn't find any issues above the wrist like Keith. It has been a real game changer for me. I can sleep now, and grip with that hand too.
Five days after carpal tunnel surgery you are out in the shop that’s impressive . Took me several weeks before I felt like doing anything stay healthy we All enjoy your videos
Just a quick thank you Keith - I really appreciate what you do. I recently got a load of vintage equipment: a DOALL ML, DEWALT G55, Landis 618, Bridgeport Round Ram and BREDA BRF 150 and your manual archive is 5 for 5. Thanks so much! I will definitely subscribe to Patreon.
For best results when surface grinding, wheels need to be balanced and trued - two distinct and required preparatory processes. Small machines have small-diameter spindles, and are likely MORE sensitive to wheel imbalance than large machines. The very common Sopko adapter
Wishing you a speedy recovery,I really enjoy your videos my dad worked in a machine shop that made parts so I am learning something about what he did for a living.
I would suggest 20 to 30 thou step over for finish cuts. Also only 5 tenths or less depth of cuts. And as many others have said some spring passes. Heat also has a large part to play when trying to get flat, parallel and perpendicular within tenths. Although with the coolant that should mitigate most heat issues
Right hand Carpal tunnel and ring finger trigger lock surgery last spring. I was down 3 months. Last week had left thumb joint reconstruction, 6 - 8 weeks in cast. then 6 - 8 in brace. I'm bored stiff, can't do nuthing. The real bugger is right thumb reconstruct is next followed by carpal on left. take care get better. Update: I bloodied my nose trying to scratch my nose with the hand in cast.
Over wheel dressers are great if your grinder has no wear in the column. If you try to dress with worn column the wheel is true to the column not the magnet which is not ideal.
Hey Keith I've been watching for quite a while and I don't think I've ever seen this Thompson grinder what an amazing machine You need to do a whole video on it!! I mean built in cluster diamond wheel dresser come on I want to hear all about that!!
Keith, we had a place nearby that had some grind wheels like that, but no hubs. They had some wheels that were kinda' like a dense Scotch Brite. They are gone now, but for the life of me, I couldn't think of a single use for them.
@@johncoops6897 that was my thought. I'm not sure what the company did with them. They had them for quite some time. They decided to scrap all of their used or otherwise fasteners, so who knows what happened on the grind wheels.
The way you touch off is not wrong but I touch off a little bit differently. With the wheel off and over the work piece I turn the wheel by hand and slowly feed down till the wheel just drags against the work piece. Also making sure the work relatively straight. For me I have less surprises. Balance wheel depends on how stiff your machine is. The Cincinnati no.2 I never needed to balance any wheels but I work a Dakota model KO lee and l have to balance almost every wheel. The difference is the Cincinnati no.2 is about 2000 lbs and the KO lee is about 1200 lbs . Makes a big difference. With the finish your getting I wouldn't worry about it.
A Thompson grinder very similar to this one sold recently in my area for $270. I was considering bidding on it, but noticed that the guard/truing assembly was missing. It's also twice as big as my current grinder...
It's better to use the magnetic placement for the diamond dresser. The "on machine dresser" introduces side play vibrations....Anyway I appreciate and enjoy what you. Thank you
wheel dressers are the best money makers there are however he does not have much experience with them. diamond on chuck is best but will run a shop out of business.
Slower side-to-side travel and finer front-to-back increments between passes does a lot to improve surface finish. How much is your downfeed each pass? For ultra-fine finishes, I will run a couple "spring" passes with no additional downfeed; stop when it sparks-out. If I were the owner of these squares, I'd have painted (powder coat) them before starting so the web would be protected.
A bit off-topic and pretty irrelevant trivia, but that sound the machine makes @ 12:06, when lifting the head, is exactly (if my aural memory serves me) like the sound made by the "dynamo" used for charging the battery in the lighthouse in Stoneship Age in the original MYST game.
Had the ulnar nerve release in both elbow after 37 year career as heavy duty mechanic sometimes wonder if I did right thing after small and ring fingers were clawing over retired after elbow pain just too much still struggling 10 years later
Nice job Keith, I always learn things watching your videos. One question on the inspection following the square-grind process. You used your magnetic transfer block as a riser, and explained that because it was the mate to the block used on the grinder and that it may introduce some error. If your 6X6 block is the gold standard, why didn't you just hang the tail end of the square off the edge of the surface plate and eliminate the riser block entirely? Obviously, you need the block for the grinding operation, but for inspection purposes wouldn't this have been simpler? Thanks -Kurt
Could you have used your cylinder square to verify the squareness once you got done with the grinding? Also, how does one determine how fast the feed is for the surface grinder? To a novice like me, it seem to be moving very fast.
Surface grinders are a mystery to me. I know the stones are different, they are cooled and the cut depth is small, but it just seems that the stone goes away a bit at a time and would lose accuracy. Just my insanity thinking out loud here. I had carpal tunnel surgery in the right hand about 20 years ago. Wasn't able to take time off the job long enough and was on it again within a week. Wasted procedure (like the surgeon said) it reversed the benefits of the surgery. Been living with it since. One of the hardest things for me to do for example is to find a screwdriver at my house, I don't have many because I have to use power tools for nearly everything so hand tools are always hiding, but I get by.
The wheel has thickness. Only the leading edge is eroded, by the time some is worn away there is more waiting as the cutting edge travels across the width of the cutting face. The diamond dresser is used to resquare the cutting face, and the process starts again. You have to wear out the entire face before any potential error is introduced, but used correctly, that will never happen. So it is one of the most precision processes we have.
@@Bakafish Ok, so you dress the wheel for each job basically. That makes sense as well as the leading edge wearing and the trailing surface finishing to spec. Thanks
@@marcp1180 Yes you dress the wheel, then start grinding, you make a pass and then check the stone, if you managed to run across the entire face, you redress the wheel. However that rarely happens because you don't normally remove a lot of material during this process. The idea is to machine it to within a thou or less over and then grind it to final size if at all possible.
@@Blazer02LS Thank you, I'm a small time hobby machinist and grinding wasn't any part of my learning experience. Thanks to y'all for your knowledge and for Keith bringing on a good video about it where I'd get the chance to ask.
@Sunlight through a window I think it was Project Farm that shortly ago did a comparison video of a few different brands of screwdrivers. The Harbor Freight screwdrivers quite shockingly did very well against many of the other expensive brands. You may just be doing people a favor by loaning Harbor Freight screwdrivers out.
So... if you need a square-ground fixture to grind the square, and known-squares to inspect the squareness, how was the "primordial" known-square made and verified in the first place?
you simply step grind it dead nuts. that is how tooling is made square from scratch. not by purchasing an item assumed to be square. his method to check the squareness after--------------------was simply wrong as his tenth indicator showed.
@@mzb8134 Thanks that was an interesting read! But my question was about the perpendicularity not the flatness. Found a book that explained how to reach the squareness from the withworth 3 plates: it's using a box with 2 opposing sides, flat and parallel, then the perpendicular side is made flat, and checked with an indicator and bumper with itself by reversing the box. (After setting the indicator to 0 on one side then flipping the box the indicator will show the double of the error in perpendicularity of the face)
I don't envy you for getting carpel-tunnel surgery, personally I was lucky enough to avoid it. I had it years ago. I was crawling under my house in the crawl space, working on a frozen drain. I moved a hot water pipe out my way, and didn't know there was a crack in a 220V wire. I got the jolt of my life, ended up with an electrical personality, but poof! carpel-tunnel gone and haven't had a problem since.
I think you could have gotten a more accurate, or at least more easily readable, 6" measurement by using a tenths indicator on a stand (like you used on the surface plate) and a 6" gage block as a setup piece to zero the indicator. Any difference off zero would have been a difference off 6" height.
I'm guessing he made most of it. The toe clamps aren't hard to make and "T" nuts aren't hard either. For the rest it's just hardware store nuts and bolts. I've made most of that stuff for myself although I don't have the cool box he's got you can get them from Canadian Tire, (in Canada), and I suspect Harbour Freight in the US.
Joe Pi made a set of these as well as a mini fixture plate....I copied his design and made the same set, use them all the time. If you want a Fusion360 design/print, send me a PM and I'll shoot you a copy.
After watching various vids about surface grinders… And the effect of magplates bending the workpice… I was wondering how much this setup, clamping on the thin web between the legs would distort the pice… my thought was that clamping maybe should have been done on the legs themselves? Any comments on that? But maybe these effects are far to small to be noticed on this part?
If the "precision block" is square, flat, and parallel to 50 millionths, why isn't the square you ground square to within 50 millionths? Where did the error come in ?
Sir, unless you get super lucky, you'll probably be making hubs for your surface grinder, looked in usual places, and used different key words, nothing, notta, not 1 that even remotely looked close, but would make a great video, hope you get feeling better after surgery!!!
So, one thing I've never quite understood about surface grinders: The wheel gets smaller every time it's dressed and used. How does the machine adjust for that?
The stone is always referenced to the work by light contact establishing a relative zero point. Then you remove the amount of material by lowering the stone from that zero point. You measure the workpiece directly, more than once as you remove material, and as you grind it the reference surface becomes more uniform and accurate. Lastly you work towards the final grind with a freshly dressed stone and light cuts after once again measuring the height and zeroing it on the surface you are grinding.
@@Bakafish ah, okay, so if I touch off, then let the head come down 5 thou, and let it run over the piece until it stops cutting, then I can reasonably assume I've taken 5 thou off the piece?
The wheel stepover sideways while grinding is a fraction of the wheel width so the wear doesn't make difference within one pass as the wear happens mainly in the leading corner of the wheel. Otherwise the wear is not an issue either, except for cnc machines where the machine needs to know the wheel size after dressing
@@paulcopeland9035 I phrased that poorly. I was suggesting that Keith put the square directly on the surface plate and use the squareness comparator to check the accuracy of the newly ground square without the fixtureing that could be introducing some error.
At about 6:30, you refer to your "clamp kit". Is that something that is commercially available or did you create it yourself? I've been looking about for something like that but have found nothing so far.
Please take your surgical repair advice seriously, Keith. I noticed some yellow bruises on your left elbow - don't rush things. Your body is currently a wee bit stressed - let it do its thing in its own time. We get older with every day that goes by. All the best from an old man in western Canada...
Hey Keith. Would it not work when measuring the surface to turn it 180° and it should be out by the same amount in the other direction if these parallels are not exactly parallel. It's how you check a carpenter's level turn it 180° on the surface and if it's out by the same amount the other direction then the bubble is on. Actually the way you did it is correct I believe. If it's out by the same amount on the same end on both services then they should be 90° to one another
Same base material, However these are then ground the same way as he is grinding that square so the the mating surfaces are as close to dead flat as they can be. Unlike the out of the box versions that are sort of flat.
Just a hobbyist, but will not the surface grinder wheel change diameter when grinding , thus not keeping the distance to the workpiece exactly the same, or does these machines compensate/ indexing somehow for this change in diameter / distance to the workpiece while grinding. Just curious.
I would like to use parts of your video as it pertains to surface grinding/squaring etc. also many of my comments would actually not involve what your doing but advanced stuff often not pertaining to what you are doing. also I could say who the person is or I could do the uploads simply not saying who the person is if you wish