Thread: Elliot 8-18 Surface Grinder

Hi all,

Well further investigation has revealed a spring place in Breaside. Hales Springs. They re-open on 5th January. They also have a spring of similar properties to the one described as S125 in the Century Springs catalog.

I have also re-united the hydraulic pump with the machine and done some testing. The pump with the "good" spring works as required although adjusting the relief valve to 200 psi seemed to put a big load on the motor and system, way more than I feel is needed. I ended up adjusting until it showed a maximum pressure of approx. 1000Kpa or about 140 psi.

I still had the issue of the table not wanting to run back and forth and putting max load on the pump, requiring the relief valve to operate. I was looking at the prospect of removing the table, saddle and then the hydraulics…. AGAIN! Not wanting to give up so soon, I starting playing with the chock control. It's the valve that adjusts the "cushioning" of the table direction change at the end of each stroke. It turns out I had it on "infinity"! I screwed it down and the table took off! Back and forth, back and forth…. It works! I was so happy to see it working, I must have sat there and watched it for near on 10 minutes. Almost as much fun as watching the shaper! In operation, the pump shows about 500Kpa or about 70 psi and no stress or leaks, well OK it does weep since there are no seals between the metal plates. That oil finds it's way back into the tank by some nicely positioned holes in the lid. Nice.

The saddle feed also works (well not now without a the pressure relief spring) as I had that going the other day. It goes back and forth in either continuous mode or incremented stepped mode after each stroke.

OK. I'm quiting while I'm ahead for now. I'm waiting for a 10" clear water filter housing and some magnets. That will filter the coolant coming from the coolant pump. The coolant tank has 4 compartments to separate the grinding dust out but as Ray has shown, some will still get re-circulated without filtering.

Once I get that up and running, I'll be in a position to give the table a lick and then mag chuck. I rekon I'll put this thread to bed once I have achieved that.

Cheers,

Simon

Figured I should pull my finger out and actually level the machine. First off I had to make some pads for the existing leveling bolts that it came with. While it's custom to make them out of round, I decided to make them out of flat bar, 65x65x20mm. Of course I had to grind them top and bottom before installing.

This brings me to the next thing, leveling the machine. Owners manual says to place a level of the table and level it front to back and side to side so it's within 0.0002"/ft or better My Starrett 98 won't do that! Luckily I aquired a Fujita 0.02mm/M level for a good price some time back. Never had a real need for it until now.

I used the 98 to get it near enough first and then changed over to the Fujita. I good plan I thought. Boy, once you get down to those sensitivities, it's bloody fiddly. Each time I thought I had it licked and then it would go off again. It was then that I realised that if I leveled with the sun shining it would change once there was cloud cover! I got it reasonably close but nowhere near what was suggested in the manual!

Is this normal for a level of this sensitivity?

Simon

Originally Posted by simonl

Is this normal for a level of this sensitivity?

Yes. It probably would have been moving just as you walked around the machine.

Just a quick upadate on the machine. School holidays has taken it's toll on my time in the shed! The machine is at a point where it's working quite well for it's age. Most of the leaks have either been stopped or managed to a point where there are no hydraulic leaks on the floor after 1/2 hours use. I have been "experimenting" with dressing the mag chuck from my t&c grinder. It's a smaller 300x150 chuck which I paid $20 for. It was in need of a good clean up so have been playing around with feed rates and grind depths. One thing I have noticed, heat is definitely your enemy when grinding. One thing that had me a little puzzled was after grinding the chuck with maybe a relatively heavy grind of about 1 thou and then letting it "rest", the sides ended up "higher" than the middle. I can only assume that the heat build up causes the chuck to expand but not uniformly. The sides being exposed to air must stay slightly cooler than the middle and so less expansion meaning the middle has more ground off. Then when it cools, there is a "hollow" in the middle leaving the sides slightly higher. Further grinding and letting it spark out seems to "even" it out. I should point out that I did this without coolant on a 60J Carborundum wheel. The coolant system is yet to be completed. Does this seem right? WRT the finish, it's not bad, from what I can tell. I do suspect that the bearings are close to the end of their life. They are a little noisy but have quietened down some after repacking with Gadus (Alvania replacement) but the races and rollers do have noticeable wear and discolouring. Replacement bearings are available on ebay believe it or not! Here they are, exact same as in the manual parts diagram: http://www.ebay.com.au/itm/GAMET-100...item4d055cdb6f I need two of them. They will give me a 10% discount for two. Well, at least they are available. Looking at the sizing, I think they are a precision 30207J. I can gets these in a P5 precision for about $140 each. Couple of questions: Is P5 good enough for this application or am I really looking for P4? Next question, if my current bearings are shagged (remember I'm reasonably happy with finish, it's just the noise they make) will P5 bearings be good enough for my particular needs? I assume a P5 good quality bearing would still out perform a shagged Gamet bearing? I'll consider buying the Gamet bearings if I think they will truly make a difference to my needs. Any advice much appreciated. Remember, this is just a stock standard toolroom sg, not a super doper high precision Blohm! Cheers, Simon