simonl
12th Dec 2016, 08:51 PM
Hi all,
I mentioned some time back that I was planning to build a hydraulic log splitter. It's one of those projects that, while I can live without it, it will come in handy. It also allows me to make use of some stock that I have had laying around for around 15 years, waiting for a suitable project.
Some time back I starting looking for the key components, a ram, a suitable engine, hydraulics and a hydraulic pump. By far the hardest to find (within a budget) was a suitable sized ram. Strictly speaking, a perfect size ram would have been a 5" with an 18 - 24" stroke in good condition. Very difficult to find especially close to home since freight is also a cost consideration.
So, when a 150mm x 800mm ram was found on ebay, in what appeared to be in very good condition, I ummed and arred for a while because it was obviously too long and too big in diameter. It was also in NSW. I did some ringing around and through Truckit I got a quote of $80 for delivery (it weighed over 100Kg according to seller) and managed to haggle the price to $250, so I bought it. Initially I decided to just keep the ram as is and work around the extra size. I only plan on plitting logs of maybe 450mm long or so. Then, looking at the construction, it occured to me that I may get away with reducing the stroke by literally cutting it down. I quick google search revealed that some people have done a similar operation but it's not common. The ram in question is a Vickers W40 series. Detailed documentation on these rams is readily available on the net.
Reduction of the ram involved three main parts. Cut the tube (cylinder) to correct length, cut the rod and re-machine a new thread for the clevis attachment and cutting and re-threading the 4 rods. A saw a couple of issues that may have brought me unstuck, the length of the tube and ram and fitting it on my 12x36 lathe and the fact that the rod was Chrome plated and induction hardened. I read conflicting stories from people machining chrome plated, induction hardened rams. I figured I'd have a go.
Easiest part, cutting the cylinder in the bandsaw. As the blade passed through I realised I'd passed the point of no return, I may have been creating scrap metal! The length was measured to allow the thickness of the piston allowing a new stroke of 550mm.
365623365624
Next, I had to find a way to face off the newly cut end to ensure it was square. I also had to incorporate a chamfer to facilitate the sliding of the O-ring seal during re-assembly. With an OD of 180mm, it was never going to fit in fixed steady. I found an old flywheel from a small honda motor (I replaced it with electric start which required replacement of the flywheel) I turned the flywheel down between centres so it would fit snuggly inside the cylinder. I don't have any measurement equipment other than a vernier for this size so it was trial and error, cut, test, cut test etc. Turning between centres using the initial bore made it pretty straight forward. I then added 3 small grub screws that would take up once inside the cylinder, just incase it had a tendency to slide from the pressure of the live centre. In reality, they weren't needed as it was a snug fit but the thought of a 700mm, 20Kg cylinder coming loose as speed also did not excite me!
365601365602365603
The cylinder machined very nicely. It also turned out that using a steady to face the cylinder would not have worked out as well because it was noticeable that the wall thickness was not even. Using the ID of the cylinder produced noticable runout on the outside. While not at big issue when facing something this long, but it would have affected the chamfer.
The finished face on the right, in comparison the factory machined cut off part on the left. I was happy with that.
365604
Next up was the rod. Before I put it in the bandsaw and hope for the best, I tested it was a file. Needless to say, it just laughed at the file, not even a mark. So I measure the required length and cut the circumference about 5mm deep with a thin blade cutoff wheel in the angle grinder. I then put it in the bandsaw and had no real issues.
I then proceeded to put it in the lathe and turn between centres and this was when I became majorly unstuck. It was too long! Beggar. A new plan. The piston end had a protrution of the rod of about 30mm. I decided to turn a piece of scrap delrin, OD to push fit in the centre of the face plate, ID to be a push fit on that protruding shaft past the piston. This registered the piston end concentric. I then clamped the piston up against the faceplate. Now, the other end needed supporting. If I could get a centre drill in the end then I had justy enough room for the TS with a dead centre, but not enough room of a live centre. The fixed steady did not adjust all the way to fit the 3" rod BUT by disassembly of the parts, I was able to shim the rod until it was at centre height (using a DTI) and then nipping up the grub screws in the steady. It only had to run for 10 seconds until I centre drilled it. It worked.
The ram originally had a 2-1/4" thread, but for my use I figured a 50mm thread would be fine. This would also allow me to use the cut off part of the rod to make a matching female thread and then weld on a clevis arrangement. The first 3mm of machining was hard going. I really gave the TCT tool something to think about. There were sparks, I'm not too embarissed to say. If my lathe was bigger I probably would have gotten away with cutting under the chrome plate in one pass but I just didn't have the rigidity to do this and so my cutting tool was punished. Once I got through the chrome plate, the induction hardening was evident until I got to about 3mm and then it machine nicely.
365605365606
When it came to machining the thread, I decided to have a go at using indexable 16 ER 60 inserts instead of my usual home sharpened HSS tools. I was just keen to give it a go. Well, to my surprise they worked a treat. They cut beautifully and I even gave up using the compound at 29.5 deg. for tool advancement. I just plunged the tool with the cross slide at about 0.2mm (0.1mm DOC) increments and got very nice results. I will be making a matching female part, but in order to test fit the female part, I decided to make another separate M50 x 2 test part out of one end of the discarded rod. Much easier to test fit a 200mm part than the actual rod. I also used thread wires to make sure I was right in the zone with the pitch diameter, that was another first for me.
The next part was to cut the threaded rods to the new required length and then re-thread the ends. The rod measured pretty much spot on 25.4mm, 1" and so cutting thread was pretty straight forward. While they were not super hard, then were obviously not MS. Maybe 1045 or 4140. They could be filed. I measured the pitch and noted they were 14 tpi. I assume a standard UNF thread but when I looked up my threads, standard UNF is 12 tpi. It turns out that this thread is called several things. 1" UNS or just simply 1"-14 UNF. I also needed to new nuts at the flange end. They were a stock item and cost all of $2.50 each. I thought that was pretty cheap!
Cutting the new thread was pretty straight forward, I even used the same insert for the M50 x 2 thread since unified threads a 60 deg anyway. I then made an easy job unnecesarliy more complex when I realised that I didn't thread the rod long enough. The thread took up before the cylinder was pulled tight! I had to put the rod back in the 4 jaw, centre it and then match up the tool with the existing thread and cut another 5mm of thread.Certainly not even close to being impossible but I was annoyed at myself! Being new to threading with inserts, I was a bit sceptical of the finish using a lathe like mine. So I took a 10x pic with a loupe. The thread finish is pretty good.
365607365608365609365610
Last part was to trim some edges off the flange at the end of the ram. The flange is designed to be bolted using the 4 x 2 slots on the sides. I don't need these as I intend to use the threaded rods. The threaded rods thread through the flange and I cut them to extend beyond, to allow to be passed through a bulkhead plate on the log splitter beam. The 4 extra nuts I bought will fix it to this.
last thing to do was clean up the parts, give it a re-spray and reassemble...
365613365614365615365616
Cheers,
Simon
I mentioned some time back that I was planning to build a hydraulic log splitter. It's one of those projects that, while I can live without it, it will come in handy. It also allows me to make use of some stock that I have had laying around for around 15 years, waiting for a suitable project.
Some time back I starting looking for the key components, a ram, a suitable engine, hydraulics and a hydraulic pump. By far the hardest to find (within a budget) was a suitable sized ram. Strictly speaking, a perfect size ram would have been a 5" with an 18 - 24" stroke in good condition. Very difficult to find especially close to home since freight is also a cost consideration.
So, when a 150mm x 800mm ram was found on ebay, in what appeared to be in very good condition, I ummed and arred for a while because it was obviously too long and too big in diameter. It was also in NSW. I did some ringing around and through Truckit I got a quote of $80 for delivery (it weighed over 100Kg according to seller) and managed to haggle the price to $250, so I bought it. Initially I decided to just keep the ram as is and work around the extra size. I only plan on plitting logs of maybe 450mm long or so. Then, looking at the construction, it occured to me that I may get away with reducing the stroke by literally cutting it down. I quick google search revealed that some people have done a similar operation but it's not common. The ram in question is a Vickers W40 series. Detailed documentation on these rams is readily available on the net.
Reduction of the ram involved three main parts. Cut the tube (cylinder) to correct length, cut the rod and re-machine a new thread for the clevis attachment and cutting and re-threading the 4 rods. A saw a couple of issues that may have brought me unstuck, the length of the tube and ram and fitting it on my 12x36 lathe and the fact that the rod was Chrome plated and induction hardened. I read conflicting stories from people machining chrome plated, induction hardened rams. I figured I'd have a go.
Easiest part, cutting the cylinder in the bandsaw. As the blade passed through I realised I'd passed the point of no return, I may have been creating scrap metal! The length was measured to allow the thickness of the piston allowing a new stroke of 550mm.
365623365624
Next, I had to find a way to face off the newly cut end to ensure it was square. I also had to incorporate a chamfer to facilitate the sliding of the O-ring seal during re-assembly. With an OD of 180mm, it was never going to fit in fixed steady. I found an old flywheel from a small honda motor (I replaced it with electric start which required replacement of the flywheel) I turned the flywheel down between centres so it would fit snuggly inside the cylinder. I don't have any measurement equipment other than a vernier for this size so it was trial and error, cut, test, cut test etc. Turning between centres using the initial bore made it pretty straight forward. I then added 3 small grub screws that would take up once inside the cylinder, just incase it had a tendency to slide from the pressure of the live centre. In reality, they weren't needed as it was a snug fit but the thought of a 700mm, 20Kg cylinder coming loose as speed also did not excite me!
365601365602365603
The cylinder machined very nicely. It also turned out that using a steady to face the cylinder would not have worked out as well because it was noticeable that the wall thickness was not even. Using the ID of the cylinder produced noticable runout on the outside. While not at big issue when facing something this long, but it would have affected the chamfer.
The finished face on the right, in comparison the factory machined cut off part on the left. I was happy with that.
365604
Next up was the rod. Before I put it in the bandsaw and hope for the best, I tested it was a file. Needless to say, it just laughed at the file, not even a mark. So I measure the required length and cut the circumference about 5mm deep with a thin blade cutoff wheel in the angle grinder. I then put it in the bandsaw and had no real issues.
I then proceeded to put it in the lathe and turn between centres and this was when I became majorly unstuck. It was too long! Beggar. A new plan. The piston end had a protrution of the rod of about 30mm. I decided to turn a piece of scrap delrin, OD to push fit in the centre of the face plate, ID to be a push fit on that protruding shaft past the piston. This registered the piston end concentric. I then clamped the piston up against the faceplate. Now, the other end needed supporting. If I could get a centre drill in the end then I had justy enough room for the TS with a dead centre, but not enough room of a live centre. The fixed steady did not adjust all the way to fit the 3" rod BUT by disassembly of the parts, I was able to shim the rod until it was at centre height (using a DTI) and then nipping up the grub screws in the steady. It only had to run for 10 seconds until I centre drilled it. It worked.
The ram originally had a 2-1/4" thread, but for my use I figured a 50mm thread would be fine. This would also allow me to use the cut off part of the rod to make a matching female thread and then weld on a clevis arrangement. The first 3mm of machining was hard going. I really gave the TCT tool something to think about. There were sparks, I'm not too embarissed to say. If my lathe was bigger I probably would have gotten away with cutting under the chrome plate in one pass but I just didn't have the rigidity to do this and so my cutting tool was punished. Once I got through the chrome plate, the induction hardening was evident until I got to about 3mm and then it machine nicely.
365605365606
When it came to machining the thread, I decided to have a go at using indexable 16 ER 60 inserts instead of my usual home sharpened HSS tools. I was just keen to give it a go. Well, to my surprise they worked a treat. They cut beautifully and I even gave up using the compound at 29.5 deg. for tool advancement. I just plunged the tool with the cross slide at about 0.2mm (0.1mm DOC) increments and got very nice results. I will be making a matching female part, but in order to test fit the female part, I decided to make another separate M50 x 2 test part out of one end of the discarded rod. Much easier to test fit a 200mm part than the actual rod. I also used thread wires to make sure I was right in the zone with the pitch diameter, that was another first for me.
The next part was to cut the threaded rods to the new required length and then re-thread the ends. The rod measured pretty much spot on 25.4mm, 1" and so cutting thread was pretty straight forward. While they were not super hard, then were obviously not MS. Maybe 1045 or 4140. They could be filed. I measured the pitch and noted they were 14 tpi. I assume a standard UNF thread but when I looked up my threads, standard UNF is 12 tpi. It turns out that this thread is called several things. 1" UNS or just simply 1"-14 UNF. I also needed to new nuts at the flange end. They were a stock item and cost all of $2.50 each. I thought that was pretty cheap!
Cutting the new thread was pretty straight forward, I even used the same insert for the M50 x 2 thread since unified threads a 60 deg anyway. I then made an easy job unnecesarliy more complex when I realised that I didn't thread the rod long enough. The thread took up before the cylinder was pulled tight! I had to put the rod back in the 4 jaw, centre it and then match up the tool with the existing thread and cut another 5mm of thread.Certainly not even close to being impossible but I was annoyed at myself! Being new to threading with inserts, I was a bit sceptical of the finish using a lathe like mine. So I took a 10x pic with a loupe. The thread finish is pretty good.
365607365608365609365610
Last part was to trim some edges off the flange at the end of the ram. The flange is designed to be bolted using the 4 x 2 slots on the sides. I don't need these as I intend to use the threaded rods. The threaded rods thread through the flange and I cut them to extend beyond, to allow to be passed through a bulkhead plate on the log splitter beam. The 4 extra nuts I bought will fix it to this.
last thing to do was clean up the parts, give it a re-spray and reassemble...
365613365614365615365616
Cheers,
Simon