Turret Troubles

[Anorak Bob]

A while back I picked up on Ebay a turret to suit my 9 inch Hercus. Bruce "Abratool" mentioned that he had acquired one for his 260 Hercus, in Joe Hovel's buried treasure thread. Others may also be familiar with these accessories and their fine tuning on this forum. One issue that I have concerns the sping loaded detent that indexes the turret. The detent occupies a slot in the casting along with a screw adjusted gib. The adjustment of the gib is tricky. To positively lock the turret in place without any rotation requires very fine adjustment of the screws. A tiny bit too tight prevents the movement of the detent. A fraction loose enables the turret to rotate maybe 1 degree.

I don't kow if the latter 260 turret had the same detent and gib setup. I am interested to find out if anyone else has encountered this sensitivity.

The other issue I have is the non alignment of the tool holder bores with the lathe spindle centreline. The bores are presently 3/4" in diameter. I would need to rebore the holes to maybe 13/16 to rectify the problem. My intention would be to use a boring head mounted in the lathe spindle.

Has anyone done this and if so, how did they go about it?

Bob.

http://www.woodworkforums.com/attachment.php?attachmentid=175059&d=1309694034

[RayG]

Hi BT,

I'm not sure I can be much help to you, nice looking turret however.

The only thing I can think of to fix your problem (without major surgery) is to install a stronger spring. Lock up the gib to the degree of tighteness that stops the unwanted rotation, and then see how much force is required to move the pin.

I would have thought the adjustment screws on the front edge would allow you to adjust the tool holder bore to align with spindle center.

Regards
Ray

[Anorak Bob]

Hello Ray,

The six screws are for the main slide gib adjustment. There is no provision for realignment of the turret bore centrelines other than remachining. If the attachment was sold separately and not factory fitted, the bores were undersize, allowing for insitu boring on the lathe it was to be used on.

That shiny spring is a longer than standard replacement.

Bob.

[RayG]

Hi BT,

If you can't make the spring stronger to overcome the friction, then maybe you can reduce the friction with some well placed ball bearings or rollers. That would involve making a new gib however...

Regards
Ray

[Bryan]

Or how about a ball or needle thrust bearing under the nut? I put one on my shaper vise screw and it made quite a difference to the handle force required. I know it's a different situation but my feeling is that it largely isolated the axial and rotational forces.

[Greg Q]

BT, is the plunger worn on the non-gib side? As I understand it, the plunger goes into the turret tightly, but is loose in its slot without gib ultra-tuning?

Can you blue the gib and plunger to see what kind of contact they have? This might be a case of a poor bearing making gradual adjustment impossible.

GQ

** My only tool in use this week is my scraper, hence all of my problems look that way ;-)

[Anorak Bob]

I had fooled around with the adjustment of the turret stud locknuts on the weekend. Overtightening them appeared to have the effect of removing the rotational play. An illusion in reality. I just slipped up to the shed for another look. The overtightening just makes it diffucult to turn the turret. I can turn it using the leverage of the handle but not by holding the turret and twisting. That tight and any play going to look like it has disappeared:doh:

GQ, the attachment appeared to have had little use when I bought it. There could be wear that was not apparent. I will daub a little bearing blue on the sliding parts and report my findings.

Bob.

[Bryan]

Bob I guess the fit is the most important thing. But just in case I wasn't clear, by nut I meant the locking handle. Looking again at your pics I don't know if you would find one (a thrust bearing) the right shape & size.

[Anorak Bob]

Bryan,

Not much force is required when tightening the handle to lock the turret rigidly in place. My problem seems to be with the detent and gib.

Bob.

[Pete F]

Bob I have no clue regarding the gib, but with the bore misalignement I take it that's because it's been taken off another lathe? Are the bores low or high? Rather than reboring them oversize (and maybe inserting bushings to bring back to size), I was wondering if you could either shim or scrape some other component of the turret to bring the centrelines back on axis? I had a mismatched tailstock that I shimmed up this way. There is quite a lot of information on realigning tailstocks on the net if that's of help.

Pete

[RayG]

Hi BT,

Just a question, in the picture of the turret lock, it shows the detent fully inserted into the slot

http://www.backsaw.net/pics/Misc/TurretLock.jpg

The other picture showing the detent, it has a bevelled end, producing a wedge type locking action. The picture above the wedge is fully inserted.

Ok, now the question, is it possible that the detent isn't fully engaging the slot when fully extended? and leaving enough play for the turret to rotate slightly..

I hope I'm explaining that clearly enough.. to my mind, the little bit of side play in the detent and gib, would be irrelevant if the detent wasn't going in far enough.

Regards
Ray

[Anorak Bob]

Ray,

I understand exactly. I think some careful blueing should reveal the depth of detent engagement. As you point out, if the detent is not properly seated, the turret will rotate.


Pete,

When I purchased the turret, it sat 15 thou too high. I machined a corresponding amount off the bottom face of the turret. A problem with reboring the the tool sockets is that the cotters will require remaching to suit the over size bore. I will have to make a jig to facilitate that task.

(An aside. The tailstock of Hercus lathe No.1 is mounted on lathe No. 2. I used a selection of brass shim material to raise the tailstock the match the No.2 centreline.)

Thank you both for your suggestions.

Bob.

[Pete F]

Sorry Bob, I don't quite understand. In your first post you mentioned that the bores didn't align with the headstock spindle. Presumably because of that you machined 15 thou off (that was lucky in it being high rather than needing to shim!). Having done that, does it still not align with the headstock?

Pete

[Anorak Bob]

Pete,

The bores are ever so slightly rotated out of alignment on the vertical axis. There should have been clarity in my initial post. I'm starting to slip up all too often! :doh: Even my spelling is flawed.

Hopefully I'll sharpen up.

BT

[Pete F]

Pete,

The bores are ever so slightly rotated out of alignment on the vertical axis. There should have been clarity in my initial post. I'm starting to slip up all too often! :doh: Even my spelling is flawed.

Hopefully I'll sharpen up.

BT

Ok, I think I understand now. So when they're indexed the bore is angled slightly up or down? If that's the case is it possible to scrape the surface you machined to tilt the bores back to alignment? ie if the bore was tilted down, then scrape the rear of the surface to tilt it back up etc.

Pete

[Stustoys]

Bob,
Does the carriage ride on two flat ways or a flat and a V?

Are you sure they are rotated out of alignment and not parallel to the spindle but offset?(like an offset tailstock)
If it is rotation there is a 50% chance you could fix it by machining the detent pin.

Stuart

[Anorak Bob]

The slideways are flat and hopefully the attached sketch will acheive what I haven't been able to do with words.

BT

[Stustoys]

Hi Bob,
Hard to imagine how that happened. As I see it machining the detent pin can only be used to rotate the tool carrier the other way. You could scrape the back of the detent slot. How far out is it?

Stuart

p.s.I only asked to be sure as I can see how you could be parallel but offet. Being out in rotation is a little harder to figure.

[Pete F]

Oh it's laterally misaligned! Wow, that's weird. I guess I'd be looking at how it could get like that if the previous owner bored the thing on a lathe.

Looking at your pictures Bob, this one in particular

http://www.woodworkforums.com/attachments/f65/175058d1309694034-turret-troubles-turret-006-large-.jpg

It looks like the indexing plate is attached to the turret by socket head bolts. Is it possible to tweak the turret around by loosening these screws? I'm guessing it shouldn't be too far out. I could envisage somebody possibly took this off to clean, paint it or similar, and it's either gone back on slightly out of position. Alternatively it's been rotated from the position it was originally bored in. The holes in the plate may be "close" to symmetrical, but not perfect. That's all assuming it's made the way I think it is, I've never seen one of these in the flesh let alone disassembled one!

Pete

[Anorak Bob]

I started delving into the throat of the bores on the weekend but was called away before I had established the amount of error. I will have another go tomorrow. I have quite a few things to check. If it all gets too hard I could always buy a lump of cast iron and make a new turret.

BT

[Pete F]

That shouldn't be necessary Bob, it can't be bored like this, and it won't wear like this, unless of course the slides on the bottom are grossly worn and I'd doubt that. So just looking at it logically, it seems to me something is not quite right with the indexing alignment. If the pin were causing it, it would be worn and sloppy. That indexing plate seems to me to be to the most likely culprit. It looks like they have alignment pins in it, but without more information/photos I can only guess that it's been manufactured symmetrical and somebody has put it back on in the wrong position.

That's about the extent of my logic I'm afraid :D

Pete

[Anorak Bob]

This may help in further discussion about this tricky attachment. I need to look at the indexing ring - part no.1321 and see if it is out of alignment and if it can be moved.

BT

[Abratool]

Bob
I read about your problems with the Hercus Turret attachment.
I mentioned that I purchased one of these Hercus Turret attachments for my Hercus 260 Lathe & used it for a long time producing accurate repetitive work.
I did experience the same problem that you encountered with the turret head not completeley locking on dead centre after indexing, in other words there was a little play as the detent was not fully engaging.
I pulled things apart & cleaned off the spring & detent bar removing any slight burrs that could have been stopping the full engagement, then applied a full flood of machine oil lubricant to that area.Presto, all was well again, but I cannot be sure of what exactly caused the problem. The unit operated from new, very well, & then that problem arose, after going through the above exercise,all was well again & the problem has not re occured.
Now getting back to your alignment problem.
To get accurate alignment of the turret means you have to machine the 6 hole turret head in your lathe.
I did this with the original, by setting up a boring bar in the headstock of the lathe,.
From memory I did this in a 4 jaw chuck so that the boring tool could be advanced each pass to take out a bit more in each cut. One could use an adjustable boring head as used in mills, which would probably be easier.
I connected the lever arm of the Turret head by a piece of heavy wire to the carriage of the lathe, & used the longitudinal feed of the lathe carriage to provide a constant feed for the Turret head to pass over the boring bar, of course locking the Turret head in each indexed position, before boring.
Multiple passes were made to bore the head out to a few thousands of an inch under .750 inches (.747") & then a reamer was mounted in the headstock 3 jaw chuck & final size of the bore was made, to .750"
This way everything was in perfect alignment with the lathe centre line axis.
I am sure you could do this with yours to open the bore up to 13 sixteenths.
All that would mean is that the toolholders, depth stop, etc for the Turret head would be made to suit the 13 sixteenths bore.
I hope this will be of some assistance in getting things going for your Turret attachment.A great tool!
I looked up the price of the Hercus Turret head & back in 1995 it was $3000.
The only change I make when using it, particularly for larger drilling is to slip a piece of longer tubing over the lever arm to provide a bit more leverage & reduce fatigue.
Its amazing to see the speed of production once things are set up & running.
regards
Bruce
ABRATOOL:)

[Anorak Bob]

Thank you for your response Bruce. I was hoping I'd hear from you.

I removed the crown wheel, the ratchet wheel and the index ring from the bottom of the turret this afternoon. These components are held together as an assembly by means of three dowels that serve also to locate the assembly on the turret. The cap screws secure it.

The index plunger ( formerly the detent), when inserted into position in the index ring, wobbled. I felt that this would be the major cause of the turret's rotational movement (slop). The photos of the setup in the vise, show an indicator movement of around 0.020" or 0.5mm when the plunger was moved backwards and forwards in the index ring.

Applying a restrained swipe of bearing blue with a cotton bud inside the index ring socket and reinsertion of the plunger revealed some wear on the bevelled face of the plunger. Both the ring and plunger are hardened. I used some very small carborundum stones to remove the high spots. The result was a much improved fit.

Bluing the plunger highlighted small raised points in the recess in the cast iron turret slide. These points look like they were created when the gib holes were drilled. I removed the high spots with a curved blade bearing scraper. Before I reassembled the turret I rotated the indexing assembly 120 degrees. It appears that when I had removed it previously to machine the bottom of the turret, I put it back on out of whack.:doh:

The indicator shows a maximum of 0.002 "runout in the bores. I think I can live with that.

Tomorrow I will fiddle about a bit more with the gib screws.

Bob.

[Anorak Bob]

A bit more testing. With the indicator set up to measure the parallelism of the tool socket bores with the lathe's spindle centreline, I found that two bores are perfect, no needle movement when the stylus of the indicator's hole attachment is passed along the bore. Three bores indicated about 0.002 " of needle movement and the final bore, 0.004". ( I wish my drill press was as good.) I have no great desire to remachine the bores. On the odd occassion that I might use the turret, I will work around the errors.

The gib adjustment is very sensitive. I wonder if that may have been a reason for the change of design that resulted in a new attachment for the 260. With the gib carefully adjusted I was able to acheive perfect repeatability when using the boring bar. The slightest play in the gib resulted less than perfect results.

Bruce, is there any chance that you could post some photos of your turret tooling setups? There isn't much clearance for drill bits. The angled turret as found on Hardinge and Schaublin lathes, would have been a huge improvement

Bob

[Pete F]

Good on you Bob, I was getting a bit worried when you started talking about machining a new turret, but am now pleased it's all worked out so well. You obviously machined precisely the right amount off the base. Nice job.

Pete

[Pete F]

Wow! I love before and after photos, very inspiring. Nice job Bob!!

[Anorak Bob]

My suggestion that the attachment did not appear to have had much use may have been erroneous. Below are the Ebay seller's photos and a couple taken on arrival.

Edit. Pete, I deleted the previous post because I found the seller's snapshots. I was fairly confident that the attachment was for a 9 because of the presence of the indexing gib screws. The 260 attachment uses a taper gib. Still, I had no idea of the condition. Took a punt.

BT

[Abratool]

Bob
Your interest in developing the Hercus Turret head got me inspired again,while you were checking things out on the Turret head yesterday in the west, I was cleaning up & polishing mine. I spent an hour or so going over things.
The detail & engineering of the Hercus is to be admired, however like you I have found that space is limited on the lathe & I have in the past made the extensions protruding out of the Turret head.... example depth stop, centre drill, twist drills all about equal length, otherwise one runs out of travel in the Turret slide.
I was "Drooling" over the beaut adjustable boring gadget you had fitted into the Turret head. Where are these made?
I was going to take some photos for you in any case, but have run out of time today. As well as being are "nutter" on engineering stuff I am also into woodwork & have been making a Red Cedar TV Cabinet for some time, which is now close to completion.
Its taken me a while to make with hand planed splayed top & raised drawer panel which is of course dovetailed in the traditional manner, & the whole thing French Polished.
I will set up the Turret & get the photos for you soon.
regards
Bruce
ABRATOOL:)

[Anorak Bob]

Bob
Your interest in developing the Hercus Turret head got me inspired again,while you were checking things out on the Turret head yesterday in the west, I was cleaning up & polishing mine. I spent an hour or so going over things.
The detail & engineering of the Hercus is to be admired, however like you I have found that space is limited on the lathe & I have in the past made the extensions protruding out of the Turret head.... example depth stop, centre drill, twist drills all about equal length, otherwise one runs out of travel in the Turret slide.
I was "Drooling" over the beaut adjustable boring gadget you had fitted into the Turret head. Where are these made?
I was going to take some photos for you in any case, but have run out of time today. As well as being are "nutter" on engineering stuff I am also into woodwork & have been making a Red Cedar TV Cabinet for some time, which is now close to completion.
Its taken me a while to make with hand planed splayed top & raised drawer panel which is of course dovetailed in the traditional manner, & the whole thing French Polished.
I will set up the Turret & get the photos for you soon.
regards
Bruce
ABRATOOL:)

I got lucky on Ebay Bruce,

Made by Hardinge in New York. Greq Q and I were discussing the quality of German tooling and I reckoned the Yanks also turned their hands to some nice delicate stuff. I have just lifted the photos below from that post.

Are you doing the real French polish thing, shellac and metho? Durable enough?

I'm looking forward to your photos. While you have the camera out, how about some detail photos of your cross slide travel stop setup.

Bob

http://www.woodworkforums.com/attachments/f65/161805d1298087910t-couple-american-morsels-hardinge-003-large-.jpg (http://www.woodworkforums.com/attachments/f65/161805d1298087910-couple-american-morsels-hardinge-003-large-.jpg) http://www.woodworkforums.com/attachments/f65/161806d1298087910t-couple-american-morsels-hardinge-004-medium-.jpg (http://www.woodworkforums.com/attachments/f65/161806d1298087910-couple-american-morsels-hardinge-004-medium-.jpg) http://www.woodworkforums.com/attachments/f65/161807d1298087910t-couple-american-morsels-hardinge-005-large-.jpg (http://www.woodworkforums.com/attachments/f65/161807d1298087910-couple-american-morsels-hardinge-005-large-.jpg) http://www.woodworkforums.com/attachments/f65/161808d1298087910t-couple-american-morsels-hardinge-007-medium-.jpg (http://www.woodworkforums.com/attachments/f65/161808d1298087910-couple-american-morsels-hardinge-007-medium-.jpg) http://www.woodworkforums.com/attachments/f65/161809d1298087910t-couple-american-morsels-hardinge-009-medium-.jpg (http://www.woodworkforums.com/attachments/f65/161809d1298087910-couple-american-morsels-hardinge-009-medium-.jpg)

http://www.woodworkforums.com/attachments/f65/161810d1298087910t-couple-american-morsels-hardinge-010-large-.jpg (http://www.woodworkforums.com/attachments/f65/161810d1298087910-couple-american-morsels-hardinge-010-large-.jpg) http://www.woodworkforums.com/attachments/f65/161811d1298087910t-couple-american-morsels-hardinge-013-large-.jpg (http://www.woodworkforums.com/attachments/f65/161811d1298087910-couple-american-morsels-hardinge-013-large-.jpg) http://www.woodworkforums.com/attachments/f65/161812d1298088275t-couple-american-morsels-hardinge-012-large-.jpg (http://www.woodworkforums.com/attachments/f65/161812d1298088275-couple-american-morsels-hardinge-012-large-.jpg)

[Stustoys]

HI Bob,
Whats the second item in the pictures for? I picked up the item pictured on ebay with the thought of modifying it or making something similar for holding threading tools but dont really know what its for.

I think longer drills were held in collets weren't they? Not having the chuck would fix your clearance problems, of course set up would be more painful.

Stuart

[Abratool]

HI Bob,
Whats the second item in the pictures for? I picked up the item pictured on ebay with the thought of modifying it or making something similar for holding threading tools but dont really know what its for.

I think longer drills were held in collets weren't they? Not having the chuck would fix your clearance problems, of course set up would be more painful.

Stuart

Stuart
This appears to be a recessing attachment that fits into the Turret head.
It is used for machining a groove or recess in a bore to take a circlip or O Ring or for recessing the bottom of a bored hole to provide clearance for subsequent operations such as tapping or the like.Also used to make a stepped bore.
The operator after boring or drilling a hole indexes the Turret head & simply feeds the attachment holding a boring bar with the appropriate tool into the machined hole & then uses the hand lever to cause the tool on its dovetailed slide to feed into the workpiece to a predetermined stop & thus produce the recess. After that procedure the operator moves the hand lever on the attachment back to its original setting & the cutting tool is withdrawn. All a very fast operation.
I hope this may be of some assistance to you.
regards
Bruce
ABRATOOL:)

[Stustoys]

Bruce,
Thanks, That all sounds right except of one thing, the adjustable stop works on the toolholder in the "forward(?)" position.
Could this be for external grooves?
Or do I have it backwards again lol

Stuart

[Anorak Bob]

Stu

My Hardinge version appears to work backwards. I will pull it apart to see if it can be reversed. Rob "Ropetangler" may have more information about yours in his Herbert manual.

Bob.

[Anorak Bob]

Don't say anything Stuart :roll:

[Stustoys]

Well now, who ever would have thought........

Maybe they set the tool upside down like a back tool post? as the stop on the in your drawing appears to be in the same place.

Need a spare?

Stuart

[Anorak Bob]

Stu,

I imagine the thing is pretty big. Maybe too big for the little Hercus. The body of the Hardinge version measures 80 x 38 x 30 deep. A dainty little thing.

BT

[Stustoys]

The mounting bar(?) is 1". You could be right the body is about 85x60x30. I'll take some pictures with a rule.
Stuart

[Stustoys]

Here you go BT