Thread: Cross slide bronze nut - grinding noise/issues

Is the top radius part of the nut ( facing towards the bed when installed ) touching any where?
What sort of result do you get if you don't lock the nut in place and let it float ?

If it's misbehaving only when turned in one direction, maybe it's the thrust surface at the dial end?

Jordan

Hi Pipeclay,

Thanks for the reply, you're always quick in with help.

I thought the nut might have been a bit prouder than the original and maybe dragging/touching. I looked for evidence that it might be touching or dragging but I don't think it is, but I might investigate this more closely as that is a good idea.

But what you have raised is something I had completely forgotten about. Locking that nut in! It is currently floating but I do recall now that there is a small hole on the front of the cross slide that I suspect is probably a locking screw for that nut! I noticed there is a hole in the nut but wasn't sure if it was meant to engage with anything. Never thought of a locking nut coming in all the way from the front.

I'm glad I asked for help because that is something I didn't even realise was there for that purpose because the nut I took out of there wasn't locked in either and just dropped out if you extended the cross slide back off the end of the screw.

I'm at work at the moment but will try when I get home tonight. The floating nature of it might explain why the problem seems a little intermittent.

Really appreciate the help. Thanks, HB

You lock the Cross Slide nut from the top ( where the round section goes through the Cross Slide ).

That hole on the top of the nut is threaded 5/16" UNF.

The hole at about 1/2" down from the top of the Cross Slide nut (the bit that goes into your Cross Slide is 1/4").

In the 1/4" hole there is supposed to be a 1/4" diameter piece of material with a 45 degree or there about point on it, and a radius on the other end to suit the bore of the Cross Slide.

The screw which goes into the threaded hole in the nut has a 60 degree or there about point on it ,this point is about 1/4" long the threaded section is about 3/16' long giving an overall size of about 7/16".

When the Cross Slide nut is installed into the Cross Slide you can nip the top screw going through the nut slightly, this should stop the nut falling out if its a bit loose while you engage the Cross Slide screw.

Once the Cross Slide screw has engaged the nut you can loosen the screw on top of the nut so as to allow the nut to float to find its own position, or if you like still leave the screw in the top of the nut nipped up, if there is any movement in your Cross Slide screw it should still pull the Cross Slide nut to its desired position.

With the 2 tapers it doesn't really matter greatly if there not spot on (I am only guessing as to what the angles really are, same as the radius on the pin that goes through the side of the nut,you just don't want any sharp edges that may cause a dag/burr and make it hard to get out) the top one pushes against the side one forcing the radius section to grab and hold on the bore in the Cross Slide.

You should be able to get a 5/16 UNF bolt/set screw from an industrial suppliers.

In regards to the small hole in the front of the Cross Slide that is for a Threading Stop and does not have anything to do with retaining the Cross Slide nut.

I keep learning

I understand the operation now. I have the 5/16" screw in there from the original but didn't realise the operation of it was to put that locking plunger sideways. That 1/4" sideways plunger is still in the old nut. I just overlooked the operation of that bit.

So given it is suppose to float or self align, it's doing that at the moment anyway.

Thanks for clearing that up Pipeclay.

Thanks for the idea Jordan. I'll check that out too. I'm pretty sure its at the nut though just feeling the tool post during operation but worth checking the dial end also is it could be throwing me a curve ball.

I appreciate the assistance guys.

HB

Hi HB,
Here's how the Hercus Maintenance Manual says to install the new nut:

ImageUploadedByTapatalk1376369356.154789.jpg

Chris

Well,

Just following up on my earlier post. I got back to the lathe to have a proper look and test some of the ideas everyone here put forward and try and actually look closer at the weird noise. I also got a call from Mal at AMH and we bounced a few ideas around. We both agreed that it sounded really unusual for the nut/spindle to do what I was describing - if that's what the problem was.

Well, marks go to Jordan. Turns out I was pin-pointing the location of the sound wrongly. I pulled the spindle out and took it all down and the back side of the front dial was like sand paper - its galled up a little, not bad but enough to produce that gritty sound I was hearing and feeling. When I put enough pressure on the spindle pushing rearward while winding I could replicate the noise. So essentially when the cross slide is moving forward its trying to pull the front dial rearward which is when the noise occurs. Variations in resistance in the cross slide as it comes across its dovetail slide varies a little and in turn varies how much pressure the front dial places on the stationary faced dial with the 0 reference on it - so that is where the intermittent nature of the sound came from. When playing by hand winding the spindle with the nut on I could replicate it, but with the nut off it I struggled to put enough pressure towards the rear to replicate the sound and hence missed it thinking it was the nut.

I put some moly on the surfaces of the dial and have quietened it down a fair bit. It runs a lot smoother. So although I was sure I was seeing very fine bronze paste in the nut, I'm pretty sure that is just normal and the slight increase in backlash is just the nut bedding in. I don't expect it will wear much more than where it is at now. There is nothing to say that when first installed and the backlash was right down to 3-4 thou that the spindle might have been riding on a slightly malformed thread start on the nut. Maybe even from me slightly knocking back that initial thread turn in as I pulled the nut into contact with the spindle - hence it tightened things up until they settled in with a bit of use.

So there it is. Many thanks to the ideas and help. Certainly makes me feel at ease that I'm not killing my nut as I worried. I just could't ignore a sound like that and keep using the lathe. Had to track it down.

Cheers, HB

This could fix it.

Jordan

My 260 Hercus lathe purchased new 23 yrs ago has only been used by me.
However during a visit last week by Mal of Aust Metalworking Hobbyist to take some measurements of the Extended Cross Slide we found excessive backlash.
A day or so later I decided to fix the problem, made up a pin spanner to suit, together with a slotted screwdriver (thanks Anorak Bobs suggestion) to remove the small front nut.
There was heaps of "crud" in the front screw bearing & related parts.
Remembering that this was the first time it had been taken apart in 23 yrs of use.
Obvious wear on the face of the graduated dial & its mate.
Set it up as per instructions in the Hercus book, & carefully machined off the wear lip, using the compound swung around to the 90 degree position & main cross slide locked.
All a very worthwhile exercise....
Backlash is now only a few thou & all is smooth & good.
Next job might be to provide oilers for the 1/8" dia holes in the cross slide & Compound slide.
The existing oil holes even though small in dia allow lots of small chips particularly cast iron & the like to enter.
regards
Bruce

I like the solution Jordan. I thought about something along those lines to space the dial off the rear face and remove that additional backlash. I also read the way Hercus suggests addressing the back lash induced by wear on this dial.

A project for a rainy day me thinks. The backlash isn't much of a bother at this stage but I'll maybe come back to it in the not too distant future.

In the meantime I have to knock over a few of the other projects I have underway.

Cheers guys.
HB

Originally Posted by Abratool

...made up a pin spanner to suit, ..

Hi Bruce,
did you bend up a piece of 5/16" MS as per the manual, or did you come up with an easier way of making it?
Chris

Originally Posted by jack620

Hi Bruce,
did you bend up a piece of 5/16" MS as per the manual, or did you come up with an easier way of making it?
Chris

Chris
I decided to machine the pin spanner from a piece of mild steel rather than bending etc
The attached photos show the pin spanner & the slotted screwdriver.
The small radii on the pin spanner is for the cross slide & the larger radii for the compound slide.
regards
Bruce

Originally Posted by Abratool

Chris
I decided to machine the pin spanner from a piece of mild steel rather than bending etc
The attached photos show the pin spanner & the slotted screwdriver.
The small radii on the pin spanner is for the cross slide & the larger radii for the compound slide.
regards
Bruce

Sorry Chris cannot seem to get photos across.

Thanks Bruce.