Hercus Mill - Oiling Longitudinal Feed Handle and Huge Movement

Hi All,

Finally have my Mill going after almost 2 years of it staring at me unfinished every time I walk into my shed.

After the initial excitement of it actually turning on when the sparky finished I have came across a few issues and needed to stop.


1. The table is hard to move in the x axis but only for the initial 50mm or so. I have looked for the oiling points in the manual (or what I have of it) and it points to a longitudinal oiling point near the hand wheel. On my machine I don't see where the oil would go. There isnt a nipple like the rest of the oiling points. Only a hold at the rear side facing downwards. I assume this isn't it as the oil would drip out. I have attached a pdf with pics to show what I mean.

2. I recall there being some backlash when I used the machine prior to buying it but nothing like I encountered when I first tried it. The table stared shuddering so I stopped. I could move the table with my hand in the x direction what seemed like a 1mm or so. I tightened the screw at the front of the machine and that lessened the movement, I could no longer move with my hand but it still chattered slightly while milling. I was not climb milling, I believe I was cutting correctly. Cutter turning clockwise and feeding starting from the handle side. From what I can see I need to remove the table and adjust a brass nut. I would appreciate any info or point in the right direction around this. ie. Do you remove the hand wheel and go from that side or take the casting of the back of the table and wind it off or am I totally wrong? I have attached a pdf with pics .

Any help appreciated..

Cheers Paul

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Disclaimer - I don't own a Hercus mill, so these are general thoughts rather than specific instructions.
For the oiling, looking at the diagram, I suspect that the oiling point that they are talking about is to oil the bush that the screw passes through. The oil would run out of a downward facing hole like that, which makes me wonder whether there should be an oil nipple there but it has been removed for some reason. (similar to the one on the Y axis handle)

There should be a way of oiling the ways themselves. It may be as basic as winding the table to the extremes of travel, squirting on some oil and then winding the other way to repeat. Larger/ more expensive machines have way oil points and then there are some with automatic oiling devices. This is a small machine, so I'm guessing it's the wind and squirt method.

One of the problems with old machines are that over time, the wear occurs where the machine moves most and as most of the time only a small proportion of the table travel is used, there is a worn spot in the middle of the travel and tight spots at either end. It sounds more like you have this issue. The fix is to scrape the ways back in but that is a big job. The upside of doing that while the machine is apart you are able to see what lubrication is built in and if necessary, improve it (add oil cups and so on).

Unintended movement can be from worn screws but can also be from worn or poorly adjusted gibs. It looks like on the front of the table there is a handle to lock the slide when cutting in the other axis. Try snugging that up just a bit to give some more resistance to movement and see if that improves things. If it does, it could be a worn gib. I can't help with specifics of how to get in but typically you will have to remove the table - probably by removing the screw to start with and then sliding the table off. There may not be a special anti-backlash nut on a machine that small. It is likely that the nut (and screw) are worn, but like the ways the screw may only be worn in the middle. Adjusting an anti-backlash nut or replacing the nut if it is a fixed type may help, but won't fully cure the problem because of that wear.

Hopefully someone with machine specific knowledge can fill in some of the detail

Michael

PS Queensland is a big place I'm told. If you refine your location to a town or area you have a better chance of finding another member nearby who can perhaps help with assessing the issues personnally

1. mine has an oil nipple on the front side - where yours it at the rear. Id say yours did have an oil nipple that is now missing. Mine just oils the handwheel shaft bearing. you need to oil the ways on mine by just squirting some up there.

2. probably a couple of issues here. Best to have the gibs well adjusted - yours looks like it has tapered gibs. not all Hercus mills did (mine doesn't). Also probably need to apply some tension with the gib locking screw. Those two things will help with the jumping around (chattering ??).

these small mills you can only take light cuts and you are best with a sharp cutter. So combine a blunt or slightly blunt cutter, cut too heavy and lose gibs - will result in chattering/jumping. Tightening the brass table nut will probably also help.

Haven't taken my table off but to get to the nut you may need to take the end cap off the table end (opposite end of table to hand wheel) then wind the table to the right till it stops then carefully slide it completely off.

You have the right screw to tighten the x axis. The screw is a push pull that works on a tapered gib

I'm assuming the difficult 50 mm is at the extreme end of the travel?
It is normal for the middle to be more highly worn. Ideally if you can work in this range, you should tighten the gib to suit this area. My hercus mill requires 2 hands to turn outside the middle area. One day I will scrape it

As for lubrication, I'm not sure there is a port for the x axis on mine. I just squirt way oil on the ways and the leadscrew.

I would check where the vibration is occurring, it might be the y axis that is loose. Note that there is a horizontal adjustment and a vertical one for the y axis gib. Regardless, I would recommend locking all unused axes when taking a cut

Thanks All for the info.

Stands to reason tat the middle moves more freely than the edges. There is still a bit of gunk on the edges of the slides so I will clean it up, oil it then move on. You may have noticed from the pics that the handle has been broken / lost at some stage and the replacement is only about 30mm of 12mm rod. I assuming a bigger handle will make it easier to move....

The cutter was brand new out of the plastic and the cut was about 0.2mm when I had the movement so I assume there is still a problem with the movement. I will try and lock the Y movement and see if that improves it. Failing that I will pull the table off with my fingers crossed and see what I see.

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Seeing from the photo that you have not fitted a power feed could your jumping be operator error?
Based on what can be seen from the photo it looks to be a full face cut across the top of your material, if that is/was the case climb or conventional milling would not be an issue.
If your 2nd photo shows cutting the edge of a piece of stock then climb milling May of come into play, either asking here or reading books may help you.

Thanks Pipeclay,

Very well could be operator error. I do have a metal trade and did machining at tafe as part of my apprenticeship but that was a long time ago (20+ years). Mostly self taught and trying to remember what I learned a long time ago. I mostly worked in metal fab and welding and never used the machining skills at work so they left long ago....

I did pull the table off tonight and have had some success. Probably 90% better with the movement. Only moved slightly on the second cut as you described and only slightly. (i will do some research there!!) The brass nut pictured has alot of wear in the thread as predicted by others and was sitting loose in its home. The hex head set screw was loose so I tightened it up to eliminate the movement. So just the play in the thread vs the whole nut moving. As I mentioned in the initial post I could initially move the table back and forward with my hand. Even I knew that there was something wrong there!!!!

I also took the chance to clean up the slides. It moves more freely now but still not prefect at the end..

Its a bit blurry but it looks to me like you have a lot of wear on the front RHS of the X axis ways, does your fingernail catch on the inner edge there? I suspect you might have the table only bearing on a thin area in the middle, leading to see-saw style rocking. Could we get a couple of closer photos?

Yes, not a good photo in hind sight. Had grease all over my hands and was trying (unsuccessfully) not to get my phone dirty.

Dont have anything clearer. I recall the first part and last part of the thread probably 5mm or so have detached from the actual nut. So you may be correct that it is only using the center of the nut. You can just see to thread in the blurry photo

I used it again last night to test out the fly cutter of a piece of ally. Worked well so I am happy enough not to pull it apart again for now.

If it does need to be replaced the brass nut looks too complicated for me to make, I wonder if its a part that can be purchased anywhere???

Oh no I meant the ways look like they have ridges not the nut. I'm sure one of us can make you a nut but half the wear will be in the screw.

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Opps, just read your post again. I dont recall seeing wear on the ways. I will take another look though.

Thanks for the info.... I didn't even think about the screw having wear. I thought with the brass being the softer material it would have been designed to wear out instead of the screw.


I will be back in the shed this weekend giving it another go. I have a few small off cuts of ally and mild steel blocks. I am happy to turn them into swarf and see what the machine can do and learn something in the process.

I have been searching the net for some small fitting projects also.. maybe make something useful??

Quote:

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Originally Posted by NoobHercusOwner

I thought with the brass being the softer material it would have been designed to wear out instead of the screw.

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Sorry, I haven't read this whole thread, but are you sure the nut is brass? My Hercus lathe has a cast iron cross-feed nut. Someone told me the blue painted nuts are cast iron and I think I see some blue paint on yours.