Hydrashift Missing 1 Speed

I have been looking at a nice Hydrashift but the current owner tells me that one specific operating speed doesn’t function. I am not overly worried because the speed is missing, I am worried about internal damage caused by particles loose in the gear case. The 2nd is parts availability if I do need to repair. The machine hasn’t had the fluids changed or the filter in 3yrs or more. The current owner claims the lathe wasn’t used that much.

Need to find out what speed it is, and why that speed isn't working. Could be as simple as the dial out of index.

You can easily pop the top cover off of the headstock and have a looksee inside for a broken gear etc.

As stated, pull the headstock cover and look inside. You'll probably also have to pull the valve body to really see what's going on, so if you do, note the position of the speed dial and don't rotate the dial or the valve spool in the valve body. Or mark both of them so that you can return them to those positions before reinstallation. Same for the positions of the shift forks and the sliding gears.

The missing speed could be due to a number of reasons. Check the clamps on the shift forks where they slide onto the piston rods in the valve body.

Parts availability is an issue with almost any machine that is this old. If you need a replacement hydraulic pump (there are two), you'll be hunting for a while, and even then you'll likely only get something close and have to make some modifications to get it to work. The Rockford Pullmore clutches can also be a problem in getting parts.

Used or not, the headstock, apron, and quick change gearbox fluids should be changed. There is no actual filter on these Hydrashifts, just two cleanable strainers. One is easy to get to on the back side (either above or below the drive motor depending on the size of your lathe), while the other is inside the headstock and requires major disassembly to remove. The factory recommended just backflushing it unless removal of the headstock gears and shafts for other repairs allowed access to the second strainer.

Check the primary hydraulic pump driven pulley under the sheet metal cover on the left side of the headstock. The keyed pulley ID on the pump shaft is a weak spot, and will start to work under load, especially since the spindle rotation direction is changed by reversing the motor drive (which means the pump drive reverses, too). Once the pulley starts working on the shaft, the Woodruff key gets loose and damages the pulley and/or the shaft.

My Hydrashift had been rode hard and put away wet. The inside of the headstock was filthy, and I ended up replacing a number of the shaft bearings due to wear.

Thanks for all the input. The lathe is 21.5 and other then missing the one speed which is in the 600 range not sure of the exact speed, the lathe is in great condition. I really like the lathe, I just worry about not being able to find and or afford the parts.

I don’t think the owner would be ok with me pulling the cover to inspect. There was not any bearing noise.

Thanks again for the input.

Yes, could definitely just be a setscrew loose on a shifter fork, or a bent or broken fork (both pretty easily fixed if you are handy with a torch and brazing rod). 3 years with no oil change is nothing in the machine tool world. There is no carbon buildup like a car engine, so the only thing to really worry about is contamination. As long as the oil is clean and nothing in the headstock is making metal, 3 years is not a problem.

Agreed that three years on the same oil would not be an issue, especially for infrequent operation. I was thinking of my Hydrashift, which had clearly not been maintained, and just an oil change would not have been enough. There were chips in the sump of the headstock (likely fell in when the cover had been removed at some times in the past), and a dark film of something on all of the internal surfaces.

If the lathe is in a non-temperature controlled location, condensation can develop inside the headstock just from the swings in temperatures and humidity. The headstock is not sealed (it vents through the brass fill plug on top), so moisture can get inside.

I'm pretty sure that I'm looking at that same lathe. I live pretty far out from Denver though and was hoping to get more clarity before making the drive. I see you didn't go for it-- any reason why? Did you get to the bottom of the missing speed issue? Did it seem like it could hold some good tolerances still? Worth $4K?

It better be tooled out the yang or you better need one REALLY bad for $4000, especially with a dead gear.

Yeah, I'm just not sure what to expect on lathe prices. It seems like you read on here about folks getting all these good deals, but I virtually never see those deals unless it's a machine that's seen better days or is on the other side of the country. I need to get a lathe for the shop that I can hit the ground running and make parts on. I don't have time to screw around with fixing something up right now. While the one speed is missing, it really does look to be in excellent shape otherwise. It comes with the following:

15.5" 3 jaw chuck and 4 jaw chuck + face plate + steady rest 3 Live Centers and many quick change tool holders and carbide indexed tooling. Soft jaws and Micrometer Stop. Aloris Tool Post, Drill Chuck

Here's a link to it: Cincinnati Lathe 21.5" x 72" - tools - by owner - sale

You think hold out for a better deal? I just really haven't seen much better come up in a long time and there's not really much on the radar as far as local auctions go. I mean, there's a JET lathe coming up for auction next month-- that's it. Other than that, there's another hydrashift (26x72)near me that's been gone through and has no tooling for $17K and a Monarch 10EE for $8K (but that's a little small for what I need).

Maybe I'm missing something, but I just don't see manual lathes going for good prices around here. Short of buying one sight unseen from 1200 miles away, I'm not really sure I have a better option.

I am going to go check it out this week. I was thinking-- I have to get 3-phase figured out for this if I get it anyway. I happen to have a Baldor 15HP VFD that I'm not using. Is it a bad idea to simply bypass the problem prone hydrshift and simply use the VFD for RPM selection? If I did this, would I want to keep it in high gear or some mid range gear? Would running it mostly in one gear for extended periods of time pose potential locking up issues from lack of shifting? If this would work, I think this would be great as it would basically get rid of the Achilles heal of this lathe, and given how good a shape it's in, I bet this would last me forever. Hopefully at least, as I gather parts are pretty spendy for this guy-- although it seems like they're spendy for any lathe...

The hydrashift system is not at all problem prone. It's super simple and well made. It works. I'd use the VFD for a converter and run the machine as it sits. I think you would run into problems with the hydraulic system if the input shaft was not turning at normal speed. You could get away with what you are saying on a manual shift lathe, but probably not on the hydrashift.

If that Hydrashift is only missing one speed, then it would be worth removing the headstock cover and doing some investigating. Might be something as simple as an adjustment to one of the shift forks.

Also, put a gauge on the hydraulic pump output per the manual, and see if adjusting the pressure valve helps.

I agree with Mike C. that you need the hydraulic pump at least to be functional, since it provides lubrication for the headstock gears, not just for shifting. I don't know what the minimum and maximum RPMs are for the pump, but my Hydrashift has a two-speed AC motor - low range is 840 and high range is 1725.

Well, I went and looked at it and it sure is a nice lathe-- very very good shape except for the missing speed (343 RPM it turns out). It sounds like they've run it without it for a decade or two, so not sure it will be much of a problem. Plus, I found out it has a taper attachment, which is exactly what I needed for a machine we're planning on prototyping!

One thing though is the guy who was selling it was just the owner of the shop that's closing. The machine operators had all been let go. I had him run it and he had no idea how to shift using the hydrashift. He ended up trying to engage speeds as though it was lever operated. He ended up grinding on a couple of gears before I stopped him and he admitted he had never actually run it. It sounded bad, but I don't think I caught the sound of anything breaking off (it more sounded like a manual transmission with the synchros going). Once I showed him how to shift it, it sounded great. Quiet as a kitten's purr. Do you think he might have damaged something right there or it's probably fine based on how it sounded afterwards?

The other thing is that this lathe seems to have a D spindle. I thought it was supposed to be an L type?

I took some measurements off of it and was wondering if you guys could help me figure out if anything looks off:

Cross Slide ways varied by around 0.002" across length of travel in relation to the apron.

V-ways looked great. They varied by about 0.00025" over the length of the lathe. He did say that it wasn't very well leveled.

Compound slide was able to wiggle in relation to the cross slide to the tune of ~0.002". The gib had about 0.25" to go though before sticking out, so I feel that I could try just tightening it to clean that up.

Backlash in the cross slide was around 0.025" on the dial

It had a 15.5" 3-jaw mounted that showed 0.0025" variation radially and around 0.005" variation on the face (towards outside of the chuck). Is this reasonable for a 15.5" chuck? I'm worried as it might be that speed is missing from a crash and want to make sure the spindle isn't tweaked.

Anyhow, I sure like this lathe. It's just got that feel that it's been well loved over the years and hasn't seen much use.

What do you think, worth the gamble?

I doubt he damaged it. When I bought mine, I had the same experience. Seller was the shop owner, and didn't know how to operate a Hydrashift, so gear clash when he tried to shift. I've since disassembled the headstock (everything except removing the spindle) and there's no damage.

You mentioned that it shifted "great" once you showed him how to operate it. What happened when you tried to shift into the 343 speed?

A D spindle was optional.

Thanks for helping relieve my anxiety over that! I've never run one of these hydraulic shifters before and when I heard him grinding on this gorgeous lathe, my heart sank.

We didn't try it. He said not to go into that speed anymore. I asked if he had checked the oil when he changed it for metal debris and he didn't recall anybody saying something. I feel like given the length of time it's been used without it and how smooth the headstock sounded, it's probably not an issue. From what he said, they had it refurbished 30 years ago, and it got used maybe once a week when they needed the length and had their 30x128 lathe tied up. I have a sneaking suspicion it's something simple and they just didn't feel the need to take the time to fix it. I also have a sneaking suspicion that I actually have no idea what's wrong and it's a major expensive fix...

Centimeter said:

What do you think, worth the gamble?

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If you need that size machine, yes I'd grab it at that price. I can't imagine it's been crashed hard enough to bend anything without leaving other prominent evidence, the chuck might be not mounted correctly, dirt behind it, etc. or might just be that out of true. If you are really worried, get permission to remove the chuck and indicate the face of the spindle. You might try just indicating the back face of the chuck right next to the spindle face it it looks like that surface is ground at the same time as the mounting face.

The rest of the machine looks really well treated.

How do you shift one of those? I've never seen one operated.

If it was grinding, it may have issues with the governor speed control. The way you are supposed to shift it is to dial the speed you want whenever you feel like it with the spindle running merrily along. When you stop the spindle with the clutch, the machine shifts to the selected gear. Hit the clutch again and it is off and running at the new speed.

That's what I had him do, and it seemed to work fine after that. Although in reading more about it, I am not sure it should have been behaving poorly with how he was shifting either. He was pulling it out of gear, letting the spindle stop, selecting a new speed, and then slowly engaging the clutch. Would this method of shifting cause grinding like observed or is this evidence of something amiss? I spoke with him today and he said he was playing with it last night (yikes! I wish he'd just leave it be) and he found it was working better now that he started heating the shop again. It was sort of cold when I saw it-- maybe 50*F in his shop. I don't know, sound like somethings wrong or that's what you'd expect from a hydrashift being operated in this manner?

I also had another thought on the VFD question. In looking at the catalog, it seems they did make several higher RPM versions of the hydrashift, depending on customer requests. I would very much like to be able to use the VFD to increase the max RPM maybe 10-20% and also decrease the minimum RPM a good amount. It would also be nice to fine tune the RPM within each range should it be necessary. It sounds like you guys aren't sure if the hydraulic pump would adapt properly if attempting to make a complete VFD conversion, but with regards to tuning within each range, does anybody know if the hydraulic pump would care very much? Was the hydraulic pump configuration changed for these higher RPM versions or did they just change the pulleys to speed everything up, which is essentially what a VFD would do?

Centimeter said:

Thanks for helping relieve my anxiety over that! I've never run one of these hydraulic shifters before and when I heard him grinding on this gorgeous lathe, my heart sank.

We didn't try it. He said not to go into that speed anymore. I asked if he had checked the oil when he changed it for metal debris and he didn't recall anybody saying something. I feel like given the length of time it's been used without it and how smooth the headstock sounded, it's probably not an issue. From what he said, they had it refurbished 30 years ago, and it got used maybe once a week when they needed the length and had their 30x128 lathe tied up. I have a sneaking suspicion it's something simple and they just didn't feel the need to take the time to fix it. I also have a sneaking suspicion that I actually have no idea what's wrong and it's a major expensive fix...

Click to expand...

I doubt that it's a major expensive fix. The hydraulic shift block has three forks (all Hydrashift lathes use the same shift block, regardless of the lathe size), and if multiple speeds were unusable, I'd say you might have one bad piston/fork assembly. But just one bad speed doesn't sound like a serious failure. I'm guessing more a hydraulic pumps (there are two) or pressure governor setting, or fork adjustment.

One thing to check is to remove the headstock end cover and examine the primary hydraulic pump and pulley. The pulley is held on to the pump shaft with a small key, and the coupling is a weak spot with these lathes. See if the pulley is loose or wobbly on the hydraulic pump shaft; if it is, you'll probably have to find a replacement pump (the shaft will probably be wonky), and that will be difficult. Or get creative with machining up a pulley for a similar replacement pump.

Also check the input pulley on the clutch input shaft at the top of the headstock. The pulley and shaft have a tapered joint with a key, and if the pulley gets loose, it will mess up the taper.