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Hydraulic surface grinder table rises .001" when traveling to the right...

Bill in PA

Hot Rolled
Joined
Jan 25, 2011
Location
Fairfield, PA
I wasn't sure if I should post this question here or in the reconditioning forum.

Elgin Alpa (Italian) hydraulic surface grinder roughly 8 x 18", 10" wheel. Hydraulic oil lubricates the ways.

I was having much trouble grinding a job today. It was grinding heavier in one direction.

1. I put an indicator (.0005") on the table. Reading the indicator with the table traverse on, with the table moving to the left, the indicator reads zero across the length of the chuck. With the table moving to the right, the indicator reads +.001".

2. Disengaged the traverse, disconnected the cylinder, and leaving the hydraulics on: Using the hand wheel the indicator reads the same as #1.

3. Disengaged the hand wheel and leaving the hydraulics on: Pushing and pulling the table by hand, the indicator reads as #1.

4. Shut the hydraulics off: After several cycles of moving the table by hand, the indicator settles (may be a few tenths change, but much better).


I think it has always done this to some degree, but it was quite noticeable while grinding today. I bought the grinder in 2011. I changed the hydraulic oil, but I don't remember what viscosity I put in it. I have some empty 5 gallon buckets of tractor hydraulic oil from Wal Mart sitting around. I probably used that. I don't have the manual and I was never able to find any information about it. Maybe it should have way oil in the hydraulic system like my OD grinder does? There is ample oil coming off the ways at each end when running.

I don't see any adjustment/restrictors for the way lube lines.

IMG_7536.jpgIMG_7538.jpgIMG_7541.jpg

Any ideas would be most appreciated.

Thanks,

Bill
 
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The restrictors for the lines would be on the hydraulic box itself probably. Follow the lines back to the tank and look for a small set screw on the valve that they come from. Thats how mine works at least. im 99 percent sure i use iso 32 in my ko lee 6x18.
The only reason i could see my table having that type of movement like yours would be if the rod for the hydralic was bent and pulled the table down from one side which would pull the other side up. Other than wear or something physically in the way like dirt and what not. .
 
I have a Norton with powered way lube. If you get carried away with the way oil it will allow the table to hydroplane. Mine has needle valves for adjustment.
 
I once ran a little Sanford hand grinder that had a similar problem. It had been used so much in the center of the travel that it would do fairly well if you stayed away from the ends, but if you ran onto the unworn part, the table would lift, apparently sucking some oil into the ways which kept the table high for the next strokes. I would be happily grinding until I inadvertently ran on the high end and then would grind a burned line down the part. The owners, who were two of the cheapest I have had to deal with, refused to have the ways scraped. I didn't last long there.

Bill
 
The restrictors for the lines would be on the hydraulic box itself probably. Follow the lines back to the tank and look for a small set screw on the valve that they come from. Thats how mine works at least. im 99 percent sure i use iso 32 in my ko lee 6x18.
The only reason i could see my table having that type of movement like yours would be if the rod for the hydralic was bent and pulled the table down from one side which would pull the other side up. Other than wear or something physically in the way like dirt and what not. .

The line for ways originates on the backside of the valve mounting plate in the box. There is no access to that side without removing the box from the top of the tank. The only adjustment that I could find was the main pressure screw behind the gauge. Current pressure is about 15 kg/cm^2. I will probably try it at a lower pressure tomorrow. I also want to see if it is any different when it is cold. The oil is still warm right now.

I have used other grinders that had table issues because of problems with the cylinder. That was the first thing I looked at. I disconnected the rod and pushed it all the way to the left so it would be out of the way. It connects at the right end only.

Thanks,

Bill

EDIT: Actually, the pressure gauge reads the cylinder pressure. It is zero when the table traverse is off. There is no gauge at the pump.
 
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Possible buildup of swarf has blocked a drain, allowing a bigger "wedge" of oil to build up in one direction? Check that everything is clean in the return path.

The oil spills over the ends of the ways and drains back to the tank. There is no trough at the ends for it to gather. I had the table off when I first got it to replace the o-rings in the cylinder. The channel at the bottom of the v way was clear. The grinder gets used little. I think this is only the second time I have used it this year so far. If I can't figure anything else out, I pull the table and take a look.

Something I might be able to determine is if the table is rising over just one of the ways or both. I'll take a look at that tomorrow.

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Thanks,

Bill
 
I once ran a little Sanford hand grinder that had a similar problem. It had been used so much in the center of the travel that it would do fairly well if you stayed away from the ends, but if you ran onto the unworn part, the table would lift, apparently sucking some oil into the ways which kept the table high for the next strokes. I would be happily grinding until I inadvertently ran on the high end and then would grind a burned line down the part. The owners, who were two of the cheapest I have had to deal with, refused to have the ways scraped. I didn't last long there.

Bill

The issue I am having is easily repeatable. It raises in one direction only (right) and drops back when it goes left. It always drops back and does not stay high. It does not need to travel to the end of the stroke for this to happen either. I ran the indicator tests more than once and with different indicators. Results were the same.

At first I was taking deep cuts with a small step-over (.015"). The issue was not as noticeable as it was when taking a lighter cut with a larger step-over. I couldn't figure out at first why it seemed to be grinding so hard with only a .0002" down feed.

Thanks,

Bill
 
My J&S 540 is hydraulic, sounds like your simply getting too much oil to the ways, in context, my ways are for want of a better term always damp with oil, its constantly flushed through, but volume wise, its realy not much, probably little more than a drip every ten seconds or so? Ways are constantly lubed, not really running on a film of flowing pumped oil if that makes sense? A constant dribble would be too much IMHO and cause the kinda issues you describe. Most the hydraulic grinders use the oil for table lube but all the ones i have been around do have adjustment, On the J&S range its a little screw under one of the control levers.

IMHO you would do really well to pull the table, you may have some gunged up oil channels that are causing this or another issue. If thats good, your going to have to find a manual or work out how to adjust it down because to me what your describing is just too much oil hydrulically lifting the table up. Sounds like yours only applies the oil in one direction of the hydrulics travel, so the adjustment - presumably runs off the hydrulics that extends the ram in that direction of travel.
 
My J&S 540 is hydraulic, sounds like your simply getting too much oil to the ways, in context, my ways are for want of a better term always damp with oil, its constantly flushed through, but volume wise, its realy not much, probably little more than a drip every ten seconds or so? Ways are constantly lubed, not really running on a film of flowing pumped oil if that makes sense? A constant dribble would be too much IMHO and cause the kinda issues you describe. Most the hydraulic grinders use the oil for table lube but all the ones i have been around do have adjustment, On the J&S range its a little screw under one of the control levers.

IMHO you would do really well to pull the table, you may have some gunged up oil channels that are causing this or another issue. If thats good, your going to have to find a manual or work out how to adjust it down because to me what your describing is just too much oil hydrulically lifting the table up. Sounds like yours only applies the oil in one direction of the hydrulics travel, so the adjustment - presumably runs off the hydrulics that extends the ram in that direction of travel.

There is a dedicated line for the ways (line on the right in one of the photos). It is oiling the ways as long as the pump is running. There is certainly more oil coming off the ways on this grinder than there is coming off of either my CNC mill or lathe.

I'll pull the table off later this morning.

Thanks,

Bill
 
I once ran a little Sanford hand grinder that had a similar problem. It had been used so much in the center of the travel that it would do fairly well if you stayed away from the ends, but if you ran onto the unworn part, the table would lift, apparently sucking some oil into the ways which kept the table high for the next strokes. I would be happily grinding until I inadvertently ran on the high end and then would grind a burned line down the part. The owners, who were two of the cheapest I have had to deal with, refused to have the ways scraped. I didn't last long there.

Bill

I am getting ready to pull the table. I did run the indicator again. It does seem to be worse when running the full stroke. Except for yesterday, everything I have run lately has been small parts in the center of the chuck.

Bill
 
Pulled the table. Ways look clean. No flow adjustment(s) under the table.

Third photo is the amount of oil pumped to the flat way after 1 minute without the cylinder operating. The fourth photo is the amount of oil pumped to the flat way after 1 minute with the cylinder operating. Adjusting the cylinder pressure up or down increased or decreased the amount of oil flow.

I'll pull the box off the tank next to see how the hydraulic lines are plumbed.

IMG_7552.jpgIMG_7555.jpgIMG_7559.jpgIMG_7562.jpg

Thanks,

Bill
 
Pulled the table. Ways look clean. No flow adjustment(s) under the table.

Third photo is the amount of oil pumped to the flat way after 1 minute without the cylinder operating. The fourth photo is the amount of oil pumped to the flat way after 1 minute with the cylinder operating. Adjusting the cylinder pressure up or down increased or decreased the amount of oil flow.

I'll pull the box off the tank next to see how the hydraulic lines are plumbed.

View attachment 226150View attachment 226151View attachment 226152View attachment 226153

Thanks,

Bill

The coiled copper tubing shown in the photos is used to control the flow rate of oil to the ways. The coil lengths were selected for a specific oil viscosity to give a precise flow rate at a selected operating temperature and pressure. If the oil viscosity or supply pressure is not what the manufacturer specified then the way lubrication will not work as intended.


Can you confirm that there is only the single oil outlet at the midspan of the flat and vee way? If that is true it would suggest that the oil is only being injected into the outlet when the table is traveling from left to right.

Hydraulic fluid and way oil have different additives. Way oil can be and is used as hydraulic fluid. Hydraulic fluid would however make a poor way oil. The generic hydraulic fluid sold at the retail stores is inexpensive because the manufacturer uses small amounts of additives to prevent oxidation of the oil, prevent chatter of sliding surfaces, and to prevent corrosion of metal parts. The fluid in tractors is changed or spilled on the ground every few hundred hours of use so there is no point in using a more expensive formulation. Mobile, Chevron, and Shell do offer these low priced products for use in tractors. They are not intended to be used in machine tools were long service life is a requirement. For these applications they offer a more expensive oil.

Robert
 
The coiled copper tubing shown in the photos is used to control the flow rate of oil to the ways. The coil lengths were selected for a specific oil viscosity to give a precise flow rate at a selected operating temperature and pressure. If the oil viscosity or supply pressure is not what the manufacturer specified then the way lubrication will not work as intended.


Can you confirm that there is only the single oil outlet at the midspan of the flat and vee way? If that is true it would suggest that the oil is only being injected into the outlet when the table is traveling from left to right.

Hydraulic fluid and way oil have different additives. Way oil can be and is used as hydraulic fluid. Hydraulic fluid would however make a poor way oil. The generic hydraulic fluid sold at the retail stores is inexpensive because the manufacturer uses small amounts of additives to prevent oxidation of the oil, prevent chatter of sliding surfaces, and to prevent corrosion of metal parts. The fluid in tractors is changed or spilled on the ground every few hundred hours of use so there is no point in using a more expensive formulation. Mobile, Chevron, and Shell do offer these low priced products for use in tractors. They are not intended to be used in machine tools were long service life is a requirement. For these applications they offer a more expensive oil.

Robert

Yes, only the center of the ways have the feed hole. One on the flat and two on the vee (one for each side).

I found the website for Alpa. I had looked when I got the grinder and did not find it then. I sent them an email regarding the correct oil. I also sent an email to a seller of the same model grinder (found on a used machinery site) to see if they would be willing to look up the spec.

Do you have an idea of what the correct oil would be?

Thanks,

Bill
 
I did not see where anyone mentioned the mechanical connection of the ends of the cylinder to the table. If the rod is secured to the table with no provision allowing the rod to float up, down, and side ways you will get screwy operation, just like you have described.
 
I did not see where anyone mentioned the mechanical connection of the ends of the cylinder to the table. If the rod is secured to the table with no provision allowing the rod to float up, down, and side ways you will get screwy operation, just like you have described.

Refer to my first post please. I did disconnect the cylinder.

Bill
 
On a jones and shipman the oils speced as vaculine 1405 at iso 30. I run a decent branded iso 30 hydrulic oil, but not that specific one could not locate a direct comparison or that specific grade when i had to replace the old. I have no issues with it in my grinder though and the slide ways are great, also use the same oil for the bridge-ports spindle.

As to the whole slide way as opposed to hydraulic oil, IMHO its not much of a issue, grinder ways are vast, the pressure is next to nothing compared to what a modern industrial hydraulic oil will see running non stop in 3KPsi hydraulics. gear pumps often running at 1.5-3Krpm see forces of multiple tons on tiny areas, swash plate pumps see even greater loads and vast amounts of sliding and heat. Grinder ways are not even loaded in comparison to that. Key thing about hydrulic oil is no real detergents so dirt drops out nice and quick. Now im not saying that its the oil you want in a manual oiler for ways, its not, you need the clingy stuff in real way oil to work there, but in a system were the oils pumped every time the table moves, IMHO the slide-way sticky additives are not as key.

Thoes oil groves are they clean? Whats the underneath of the table like? if something is gunged up that may be why pressure is building and the table floats up. The table should be grooved underneath to spread the oil along that grove needs to be some what open ended so it does not build pressure, just keeps the whole ways surface wetted.

Might be worth seeing if one of the scraping guys jumps in if that flaking is worn too thin that might also be making your issue worse. That hole and grove is just to distribute it to the upper moving table ways.
 
On a jones and shipman the oils speced as vaculine 1405 at iso 30. I run a decent branded iso 30 hydrulic oil, but not that specific one could not locate a direct comparison or that specific grade when i had to replace the old. I have no issues with it in my grinder though and the slide ways are great, also use the same oil for the bridge-ports spindle.

As to the whole slide way as opposed to hydraulic oil, IMHO its not much of a issue, grinder ways are vast, the pressure is next to nothing compared to what a modern industrial hydraulic oil will see running non stop in 3KPsi hydraulics. gear pumps often running at 1.5-3Krpm see forces of multiple tons on tiny areas, swash plate pumps see even greater loads and vast amounts of sliding and heat. Grinder ways are not even loaded in comparison to that. Key thing about hydrulic oil is no real detergents so dirt drops out nice and quick. Now im not saying that its the oil you want in a manual oiler for ways, its not, you need the clingy stuff in real way oil to work there, but in a system were the oils pumped every time the table moves, IMHO the slide-way sticky additives are not as key.

Thoes oil groves are they clean? Whats the underneath of the table like? if something is gunged up that may be why pressure is building and the table floats up. The table should be grooved underneath to spread the oil along that grove needs to be some what open ended so it does not build pressure, just keeps the whole ways surface wetted.

Might be worth seeing if one of the scraping guys jumps in if that flaking is worn too thin that might also be making your issue worse. That hole and grove is just to distribute it to the upper moving table ways.

Thanks for the response. Much of the flaking is worn off the bottom of the table.

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Bill
 








 
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