Thread: Elliot 8-18 Surface Grinder

Thanks Phil I may as well just PM you my updates, it seems that it's not of much interest to others, which I can understand. I pick and choose what threads to read as well so I'm not offended in any way.

Anyway, I have an update on the hydraulic bench test. It got off to a shaky start yesterday after the pump refused to turn over after I took it apart to clean and re-assemble. After checking clearances on the surface plate with a DI and finding everything to be good, I found out what I had done wrong. It's a twin pump system with two drive gears (metal) and two driven gears (bronze) Looking at the wear faces on the gear surfaces, I had put one of the gears in the wrong way round. While it still meshes fine, I figured given it's age and wear it's probably a bit fussy if it doesn't go back the same way. After that was fixed, it worked fine.

Anyway, all seems good wrt the hydraulic system. the traverse piston works fine as does the direction change lever. The damping adjustment on the direction change works lovely even though I have no idea how it works or where the part is that does it! The cross feed also works as does the amount of cross feed adjustment. The only thing I can't seem to get working is the "park" feature, although it could simply be that I don't understand it's function yet. I was under the impression that it parks to table to one side while the spring loaded lever is held.

Leaks, well there are a couple of leaks but really, nothing that you wouldn't expect from a machine built in the 60's and done a fair amount of work. Most of the levers and controls had a small drop from them after about 2 minutes of work which is to be expected I guess. None of my gaskets or seals leaked including either of the rams which I'm happy about. A small amount of oil was also starting to emerge in one of the lubrication reservoirs that feeds the ways and a couple of other ancillary items. There is another of these on the other side but no oil showing during the test. I may have to investigate this further.

Yesterday I also noticed in the parts diagram that there is a small catch tray under the hydraulics which has a drain that goes back to the resevior. This machine is missing that. Although it's missing, I find a small amount of comfort in knowing that leaks are expected and there is incorporated in the design a means of dealing with it rather than is spilling out over the floor. I intend making a small tray fit in it's place. Then any leaks will be contained in the tray and be of little consequence anyway. The only other way I can see oil escaping is from a leaky seal in the traverse ram but these are nice and tight with no sign of a leak since the replacement of the seals.

I guess the simple biggest issue at this stage is the chain and sprocket drive system on the pump. It has a fair amount of wear and as such will not properly mesh. It needs to be adjusted fairly loose in order for the chain not to bind up on the sprocket. It still runs but it jumps about a bit and sounds terrible. AT first I thought I may replace it with a belt but then on further thinking it occurred to me that perhaps the cylindrical roller bearings in the pump are not designed to take such load from the tension of a belt. I may have to look for a new sprocket set, one day.

Well, that's it for me today, it's the SWWMBO birthday today. I bought her a bird bath and promised to install it today in the front. It'd getting concreted in just in case that pot plant thief takes a liking to it!


Edit: Park feature works fine too. It interupts the auto traverse up and back of the table and parks it to one side until the lever is released again. Then it continues.

Cheers,

Simon

Originally Posted by simonl

... I intend making a small tray fit in it's place.

Good thing that pan brake is done!

Michael
(I do read but have little I can add to your adventures)

I know Michael same same with me on some of these threads. What I should have said earlier is that I pick and choose what I reply to since I cant always contribute in a meaningful way so while I read many threads, some I dont comment on. My threads are no different.

As for the pan brake, no its not finisged yet (but you knew that Michael!). It gets pushed back when something more fun comes along! Besides I need a SG to grind the fingers nice and flash! and besides, I kinda get bored if I work on just one project for a long period of time!

Considering when I started the pan brake project I didnt even have any use lined up for it, there's a list accumulating!!

Simon

I would stick with the chain drive for the hydraulic pump. I think that a vee belt drive would overload the bearings in the pump. Most hydraulic pumps don't like lots of side load of the input shaft. you should be able to pick up some stock sprockets fairly cheaply and bore them out to suit your appliction. I wouldn't let them get too worn it could end very badly.

Originally Posted by snapatap

I would stick with the chain drive for the hydraulic pump. I think that a vee belt drive would overload the bearings in the pump. Most hydraulic pumps don't like lots of side load of the input shaft. you should be able to pick up some stock sprockets fairly cheaply and bore them out to suit your appliction. I wouldn't let them get too worn it could end very badly.

Agree. Keep in mind that sprockets come in taperlock types as well so it's pretty easy to get the pitch & tooth count you need and buy the correct bushing to suit shaft size. I try to use taperlocks wherever I can as it makes assembly/disassembly easier plus when (not if) you buy the wrong size sprocket, it's easier to re-use it at a later date.

OK the taperlock types cost more, but so what, it's a PITA to bore a pilot hole one out then put in a keyway, and I have a slotter to do the internal keys. However, I am bone idle.

PDW

WRT to the chain and sprocket, I figured there must be a reason for it rather than a V belt, apart from the fact it may slip and wear with oil leaking on it. Smarter people than me design these machines. I will keep an eye out for some sprockets of suitable size and pitch, although at this stage in the cleanup it's not a priority yet.

Agree, Taperlock are a good system, once you learn how to remove them!

Cheers,

Simon

Originally Posted by simonl

As for the pan brake, no its not finished yet (but you knew that Michael!)

Well maybe, but like just about everyone else here I like other people to finish their projects as it distracts me from all the half finished ones in my shed.

Michael

Simon,
keep the progress report coming - I look forward to the updates.
It's even stirred me into continuing with my wet conversion of my SG. I'm now at painting stage fo the guards and cooland system....

WRT the chain and sporckets: our local bearing centre has hundreds of sprockets of all kinds of pitches - along with numerous chains by the roll - in stock. I would imagine your local bearing serivces would too.

No worries Joe, I have since looked online and it does appear that they are indeed quite common. I need a couple more seals, so next time I'm at the bearing shop I will sus it out. I can't see the grinder being used with the pump in it's current state, it's too noisy and quite distracting as I expect the chain to either jam or jump off at any second. It is sufficient for use to test though.

Cleaned the Z axis attachment thingy today. No surprises and nothing much to report. Very little wear of those surfaces. This basically leaves the base to clean now, along with a handful of ancillary components such as the wheel guards etc. etc.

BUT, I need the pressure washer to do that. I recently bought a couple of new parts for our washer, a new unloader valve, hose and a paver cleaning attachment. These were mostly not compatible with my existing pump and so needed an adapter piece. One I have made, for the inlet which is M18 (with O ring seal) to the pump and then 3/4" BSP for the hose connection. Done that out of 316. Now I need to make an adapter for the pump outlet to go between the pump and the unloader valve. Needs to be M18 (with O ring seal) to 3/8 NPT. Looks like I'm doing that Friday morning!

Simon

Well after doing my husbandly cleaning duties, I managed to get down to the bearing shop. Bought a new seal for the hydraulic pump and looked at their chain and sprockets. Turns out my chain was shagged and although my sprockets do have some wear, they mesh beautifully with a new chain they had in stock. For $25 I had a new chain and a seal.

Re-fitted the seal, sprockets and chain and gave it a whirl. Runs beautifully. I was surprised at how quiet the chain drive was. So that battle has been won!

Only thing that puzzles me is the direction of rotation of the gears in the pump. I always thought that the oil was pumped and pressurised when forced between the two meshing gears. Given that the inlet is at the base and the delivery of the pump is at the top, I temporarily wired the pump to run accordingly but no oil was pumped out of the delivery, it pumped it the other way round. Easy fix, I just swapped a couple of wires but it brings into question my understanding of how these hydraulic gear pumps work. Given the direction of the pump when it runs, I can only conclude that it develops pressure and pumps the oil in the small amount of clearance between the gear and the outer CI wall.

Have i got this correct?

Simon

Yes, with any gear pump where the gears mesh is essentially a seal, the oil does not go through there..

Originally Posted by simonl

Re-fitted the seal, sprockets and chain and gave it a whirl. Runs beautifully. I was surprised at how quiet the chain drive was. So that battle has been won!

I don't know what was present originally, but it may be worth while making up a cover for the chain so that it does not get grinding grit settling on it. There are lubricators available for chains (or you could even have the larger sprocket running through a puddle of oil) that will help stop wear due to metal on metal - mind you for the price of the chain you may be better off just replacing it when it starts to get noisy.

Michael

Hi Michael, It has a chain guard but I have just left it off for now while I get the pump and chain sorted. I probably re-install it now. I'm confident that the chain will last me a very long time given the amount of use the machine will get in my possession. I'll probably just give the chain some of my chain lube from my mountain bike. Cheers, Simon

Well after it was explained to me the benefits of running the spindle motor by VFD, IM keen to fish out the star point. Not a major issue but the motor is totally enclosed and has this label. Does this make things different? Is it "more balanced" do I need to take special precautions if its disassembled over and above the usual?

Cheers

Simon