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Stickslip on worn cylindrical Grinder

Richard King

Diamond
Joined
Jul 12, 2005
Location
Cottage Grove, MN 55016
I was looking at some old photos and saw this vintage cylindrical grinder that Minnesota Grinding had me repair. They bought the machine used and the ways were shiny in the middle with no scrape marks left, but the ends had scrape marks. Normal scrape marks are .0002" in to .001" max deep. For those of you who don't know, stick slip is when the ways have lapped together like rubbing gage blocks together and they wring together from 100% contact. Without oil the initial start move the table jumps sideways. Not sure how much, probably at least .010.

Once it moves the oil film lubes between the ways. But when you shut off the machine the 100% contact squeezes out the oil.
It's a Landis Grinder with a sticker on it that says WW 2 paint finish. As many of you know I don't like to 1/2 moon oil flake exposed to the air. Normal 1/2 moon flakes measure .002" deep. The bed on the grinder ends are exposed to the air. I was in a dilemma with this one as I didn't want to bend over and square cut the bed and 1/2 moon the bottom of the table.
So what I did was to 1/2 moon the bed but I sharpened the blade with a negative 15 degree rake. Normally you sharpen the blade to negative 5 degree. Here are some pictures.
 

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One issue these old machines had was the oil grooves were cut straight on the table and you can see on the bed the table grooves did not wear the bed where the road. See pictures. Also in a couple the iron on the 100% contact is about to pull out and cause a score. The photo that shows this is at the top above the oil grooves. That's why I recommend cutting in zig zag or diamond shaped oil grooves.
 

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Hi Rich,

thanks for posting these. One question: does the 15 versus 5 degree rake make the half moon scrape marks shallower?

By the way, the square cutting that you had me do on my Studer cylindrical grinder completely eliminated any stick slip. I can creep feed at 0.1mm/minute (that's 0.004"/minute, only visible on the DRO) and it is smooth.

How are you doing? Have you recovered from the fall and arm/shoulder damage?

Cheers,
Bruce
 
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Oil grooves..showing unworn areas.
 

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Hi Rich, thanks for posting these. One question: does the 15 versus 5 degree rake make the half moon scrape marks shallower?

By the way, the square cutting that you had me do on my Studer cylindrical grinder completely eliminated any stick slip. I can creep feed at 0.1mm/minute (that's 0.004"/minute, only visible on the DRO) and it is smooth.

Cheers,
Bruce
Yes..thats why I - 1/2 moon flaked the bed. I have only saw this one other grinder. It was an Italian Crankshaft grinder. The ways were narrow that caused the machine to wear super fast.
 
The one photo shows me bluing up the headstock dovetail. You have to do this before bluing up the head to the swivel plate. Think about if the dovetail is .005" high in the middle and you rubbed it back and forth the way would blue up, but you would get a false reading. Plus how can you check the hinge of the dovetail? You can't, so you check it before hand with a straightedge. You also relieve the center 40% .001 to .003" when your finished, so as it wears it gets better. Leave it perfectly flat. As it wears it gets worse.
 
Thanks for posting.

OT
Richard I was planning to pm you and ask but I'll ask here as it is sort of relevant. Stripping cleaning and painting a 1986 Victor lathe, would you flake the carriage upper. There are slight scrape marks visible on the carriage in some areas. Reason I ask is that the bed way is hardened. I will flake the cross slide upper and fix the bodgy lube track as it is unhardened cast iron on cast iron.
 
Thanks for posting.

OT
Richard I was planning to pm you and ask but I'll ask here as it is sort of relevant. Stripping cleaning and painting a 1986 Victor lathe, would you flake the carriage upper. There are slight scrape marks visible on the carriage in some areas. Reason I ask is that the bed way is hardened. I will flake the cross slide upper and fix the bodgy lube track as it is unhardened cast iron on cast iron.
Many builders 1/2 moon the exposed surfaces like Bridgeport. If you measure your depth and it's not to deep or less then .0.0005 I would say yes. Under the saddle no problem as it's covered. I've seen many Bridgeports with scores. After you remove the wipers I've found ckips under there. Most flaking is .002" deep. Also many blow chips under the wipers when the use an air hose . A real builders best friend..lol. clean with air...lol
 
Many builders 1/2 moon the exposed surfaces like Bridgeport. If you measure your depth and it's not to deep or less then .0.0005 I would say yes. Under the saddle no problem as it's covered. I've seen many Bridgeports with scores. After you remove the wipers I've found ckips under there. Most flaking is .002" deep. Also many blow chips under the wipers when the use an air hose . A real builders best friend..lol. clean with air...lol
Thanks Richard. Nothing will be exposed to air, if I catch someone on my machines cleaning with an airline I will personally strangle them with it.
 
In had a call yesterday from a company in Massachusetts who had an older Studer cylindrical grinder like Ballen has (look at sticky at the top of the thread list above) It's an iron-on iron way system and it has stick slip. He said it grinds long shafts OK but when the plunge in and move to the left or right to grind a shoulder it jumps from stick slip.
I told him to join PM and read the Ballen thread and this one. I also told him about a friend of mine up here in MN who specializes in rebuilding Studers. He said the flat way under the table is starting to score. I also told him to call around to local rebuilders and tell them the grinder needs a "cut and flake" - That's a term rebuilders use to explain what I did to the Landis. If a machine grinds accurately but has stick-slip you can give the machine new oil pockets so the table or sadle floats on a film of oil. As is said earlier the ways get stick-sion like wringing to gage blocks together. I am teaching a class today and got to go....chat later.. I also have a June class if anyone wants to attend and learn how to scrape. Look at the 2 threads I have on here about my classes. Rich.
 








 
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