|Kiwi Bloke||20/08/2020 10:27:13|
|483 forum posts|
Hi folks. Has anyone here any experience of machining the chrome-plated, centreless-ground rod from which hydraulic ram rods are made? Will tipped tooling (or even HSS) cope with the chrome layer, and without peeling it off (assuming it's well-plated, of course)? And what about drilling and boring? The 1 3/4" dia. rod needs a 1" diameter cross-hole at one end. T'other end has an axial 5/8" UNC threaded hole, about 1 1/2" deep. (Imperial units because it's an old fella). This end of the rod should also be faced and tapered so it can be inserted past the seals without damaging them. It's a pretty simple job, but the material may be a difficult opponent.
The only grinding facility I can throw at the job is an angle-grinder, with an old bloke behind it.
I'm contemplating machining this (these?) myself (on a big, borrowed lathe - the rods are 37" length overall), because the cost quoted by a local reconditioner / manufacturer made me sit down smartly - and involuntarily. On the other hand, the raw material may be horribly pricey here in expensive NZ, so perhaps the quote is reasonable. The catastrophic failure of my tractor's front-end loader (well-loaded at the time, of course) was spectacular, although not actually dangerous, thank goodness. Wife and dog know well to stay clear of anything attempting to defy gravity.
|not done it yet||20/08/2020 10:45:34|
|5140 forum posts|
I expect the ram(s) need a flat as a ‘starter’ at the cross drilled end? Removing the first of the chrome, to give a start would help - the angle grinder? Seals may not be cheap. Selection help might be available on the ‘Abom79’ vids of him sorting hydraulic cylinders and rams, although doubtless there are other sources.
I don’t expect the chromed rams will be cheap, so getting more quotes might make sense. We used a specialist some 30 miles, or so, away. We rarely ever changed seals in the workshop, let alone machining jobs like that.
Double acting or just single? Diameter of cylinder?
Edited By not done it yet on 20/08/2020 10:48:51
|136 forum posts|
I seem to recall our local (U.K.) ag. engineers replacing a bent ram rod with plain steel as an emergency repair many years ago. No idea what grade of steel, and of course it needed regular greasing to prevent rust, but it lasted many years. Might be a cheaper alternative if funds are tight?
I had a similar shock recently when it came to replacing the tipping ram on a 30+ year old trailer, just about the same price as the trailer originally cost! But I was pleasantly surprised to find an exact (imperial) match for the original, and I have a usable trailer again.
|pgk pgk||20/08/2020 11:20:48|
|1973 forum posts|
It might be worth a punt for a scrap ram of suitable size?
|Mike Poole||20/08/2020 11:26:48|
2809 forum posts
I machined a 7/8” hard chromed rod for the column of my universal pillar tool. I didn’t have any trouble but I only reduced one end to 3/4” and faced and chamfered the other. I used a tipped tool but didn’t have to plunge into the plating, there did not seem to be any inclination to peel the plating. There seems to be a ready supply of rod from Chinese sources, imperial sizes might be a bit more rare.
|Brian Wood||20/08/2020 11:39:35|
|2287 forum posts|
I have machined hydraulic ram bar in varying sizes. It is not a problem at all, the chrome layer turns off readily with tipped tooling. It drills and can be tapped easily too.
At the agricultural engineers where I last worked we made our own hydraulic rams for some of the equipment we sold; the cylinders were made up from thick walled honed bore tube, also lovely stuff to work with.
|Nicholas Farr||20/08/2020 11:53:06|
2479 forum posts
Hi, the last two places where I worked, often made new chrome piston rods, they never had any problems with it, I think the standard stuff is EN8. I have also turned, drilled and threaded some scrap ones for odd little jobs and had no trouble doing it.
|Keith Gibson||22/08/2020 19:18:37|
|10 forum posts|
In the past I have used a company called Steerforth Hydraulics,(In the UK) who supply cylinder components for self completion, I am sure there is someone in New Zealand who does a similar thing, such as Power Farming Parts Direct, or RAMSPECS in Aukland, thers's plenty to choose from.
|colin vercoe||22/08/2020 21:05:46|
|49 forum posts|
Best to groove the rod with grinding disc where the machining is to finish so that the chrome is not lifted from parent metal, also for cross drilling remove the chrome on both sides of rod for the same reason, the company where I worked used pre ground stainless steel bar available in various sizes which is used for hydraulic rams and we made our own.
Hydraulic ram specials are not that expensive at about £150.00 - 200.00 quid each, try a company called Applied Fluid Power from St Austell Cornwall you might be pleasantly surprised.
|John ATTLEE||22/08/2020 21:13:27|
|7 forum posts|
I am with the optimists. I have made new rods for a cylinder before with no difficulty. You can buy the chrome plated bar from stockists. I get my seals from Hydraulic Equipment Supermarkets. If you cannot get the correct seals, you can make a new piston to suit seals that you can get. You can usually find the dimensions on the net.
If you cannot operate a lathe, repairing a hydraulic might appear to involve rocket science. In fact, it is simple enough if you can use a lathe.
We had an interesting problem with the REME Museum's 60 ton tank transporter. One of the double acting rams on the rear ramps was leaking oil out of the top gland. The reason was that although it looked identical to the other one, it was only single acting! So we modified the gland nut to take a pressure seal rather than just a wiper. A new piston to suit double acting seals was machined. It was actually made by Andy A , another forum member.
One point that I would make is that it is essential to make a proper tool to unscrew the gland nut, especially on an old piece of equipment. I am currently working on the mast cylinder of my Hyster S40C forklift. It was a good job that I made a special tool because even the 1" drive air wrench had to work a bit to unscrew it. It turned out that the threads were a bit rusty. A C spanner or cold chisel would never have done it. Once the drive slots or holes are damaged you are in serious difficulties.
|459 forum posts|
Hydraulic rams - how easy/safe is it to remove the rod from the cylinder? There is not much force on the ram and no fluid leak.
|not done it yet||22/08/2020 23:25:14|
|5140 forum posts|
you might be pleasantly surprised.
He might be unpleasantly surprised at the shipping costs. The clue is in his screen name.
|Kiwi Bloke||23/08/2020 06:03:25|
|483 forum posts|
Thanks everyone for the information and links. All very useful and thought-provoking. It sounds encouraging too, if I decide to make new rods. Having now removed the loader from the tractor (a multi-gorilla job, but actually done by wife, self and swearing), I'm wondering how to proceed. The loader is badly designed, poorly executed and horribly worn. Previous owners clearly didn't posess a grease gun.
My preference for precision and things being 'just so' has to be weighed against the sheer difficulty - and expense - of restoring the horrible thing. All the pivots have worn their pins considerably, but the 'bores' (to dignify an 'orrible, irregular oval hole with an acceptable engineering term) should really be attended to. That would seem to require a magnetic drill and Rotabroaches (neither of which I have) to hog out the metal around the hole, then weld in a replacement hole (anyone tried to weld a hole?) - you know what I mean...
At some stage, reality has to be faced. I think I'll replace the seals and the battered rods and leave the pins and pivot holes as they were. It can only be an improvement on what it was before, and it's likely to outlast me - unfortunately... But it offends my desire for, if not perfection, doing the job properly.
Any further thoughts, however, would be gratefully received...
|Pete Rimmer||23/08/2020 07:08:38|
|809 forum posts|
Our machines at work have induction-hardened hydraulic ram piston rods. They are machinable with carbide and give a superb finish until you're through the hardened layer then the machinability increases but the finish is not nearly so good.
|Nicholas Farr||23/08/2020 07:14:10|
2479 forum posts
Hi Kiwi Bloke, yes I have built up holes in such machines (the holes being 50 to 70mm diameter) however, there used to be a contractor that my old company I worked for, hired to grind the holes back to shape with a die grinder with those drum type sanding tools. It was amazing to watch him and he could get them too, what looked to be a perfect round hole, and this would be with the said part still on the machine.
|not done it yet||23/08/2020 08:06:07|
|5140 forum posts|
The temporary ‘quick fix’ for oval holes is longer (hardened) pins and thick washers welded on.
|Kiwi Bloke||23/08/2020 09:08:24|
|483 forum posts|
Nicholas, I admire the skill of your contractor. I suppose I could grind a hole reasonably round in 1/8" thick stock, but some of the pivot bores are in considerably thicker stock - and they have to be co-axial with the hole on the other side of the rod or cylinder. Rather than building up the walls of the worn hole, I was thinking of welding in a 'tube' - like a very thick-walled bush. Lower skill level required!
NDIY, good idea. The trouble is that the pin should have an anti-rotation snug (or whatever), and, whilst I can machine the pins, getting them heat-treated just adds to the expense and hassle. It all starts to get difficult...
Having looked at the thing in more detail, I think that the loader offends me so much that I just don't want to spend the time, effort and money on the ghastly thing. It will always be crude and ugly. There are more important and urgent things to attend to, let alone the things I'd really like to do. As a friend sagely pointed out, one's time may be running out far more quickly than one's money, so buy your way out of hassle, if possible. Well, I'm terminally tight, so I think I'll do a bare minimum lash-up fix, cross my fingers, and walk away, whistling.
Thanks again, everyone, for your ideas - all appreciated.
|146 forum posts|
Not sure exactly what the prevalence of steel-framed buildings is in NZ, but here, nearly every non-domestic building of the last 40 years is done that way - hence "Mag-drills" have become a standard builders/farmers hire item..
|Nicholas Farr||23/08/2020 09:55:57|
2479 forum posts
Hi Kiwi Bloke, I do understand your dilemma. Most of the holes that I did had a pair and were at least 25mm thick on the beams, but one I remember doing, had three holes in line and building up the middle hole wasn't really a walk in the park, but it was one of the 70mm ones which gave a bit more room. As I said, this grinder guy was truly amazing with his skill and the pins always fitted without any slop or tight fits. I bet his price was on the high side but when you think replacement parts could be as much as 10 grand or even more, plus the time to remove the old part and fit new, it was probably quite a small cost. The only trouble with putting a thick walled bush in, is it might compromise the strength of the beam and of course you do run the risk of loosing the centre distances. If you go the bush idea, I would suggest putting the thinnest one you can get away with and you could probably get away with only having to remove 80 to 90% of the oval shape, but make the bush a fairly tight fit in the hole but not so that it distorts the bush.
Edited By Nicholas Farr on 23/08/2020 09:58:14
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