Lathe carriage problem

[Mathew LeeParticipant @mathewlee79288]

Hi,

I'm having a bit of trouble with my Warco GH1232 (doesn't help that Warco are shut for the hols) – I was skimming a round bar with the auto feed, I didn't notice that I'd run out of travel due to the leadscrew cover.

I don't think I broke anything, but now the carriage travel is binding somewhere: anyone got any ideas?

My current thought is that it might be something to do with the keyway slot in the bar that drives the automatic feed… No idea how to disassemble it!

Thanks, Mat

[Mathew LeeParticipant @mathewlee79288]

[Les Jones 1Participant @lesjones1]

Hi Mat,
Does the fine feed mode on your lathe use the lead screw or the rack and pinion ? Does the binding still occur winding the carriage by hand ? Does the binding occur in synchronism with either the rotation of the lead screw or the carriage handle ? Sorry I am only asking questions but looking at what is happening is the best way to find the problem. You may also have to look to see if the binding occurs in synchronism with any of the gears in the feed gear train.

Les.

[TerrydParticipant @terryd72465]

Hi Mat,

I had a similar problem on my Warco lathe. A different model to yours but could be a similar problem. If you study the parts list there is a shear pin in the drive gear on the end of the shaft. This is designed to shear in order to protect the machine in the type of event you describe. If you don't have a spare in the supplied toolbox a piece of brass of suitable diameter will substitute. Don't use steel just in case of further 'accident'.

I'll have a look at my parts list later as it is in my detached workshop and I am in my pyjamas at the moment – not a pretty sight

Regards and seasons greetings,

Terry

[TerrydParticipant @terryd72465]

Hi Mat,

Oout of 'jamas now (but fully clothed), so here is a scan of my gearbox parts list. The pin is item 16 and secures the gib key collar (item 15) to the input shaft of the gearbox.  Click on picture to enlarge:

 

Hope this helps,

Seasons greetings and Best regards,

Terry

Edited By Terryd on 23/12/2012 10:11:41

[Mathew LeeParticipant @mathewlee79288]

Les:

Lathe uses the rack & pinion for feed, the bind is there when I wind by hand. The feed / half nuts appear to work, so if feels like something has been knocked out of adjustment somehere? Not having investigated, does it have gib strips or something?

Terry:

Thanks for the diagram, I need to dig my manual out, it did mention shear pins, is it possible that they're half sheared and half working? How hard is it to disassemble?

Thanks, Mat

[TerrydParticipant @terryd72465]

Hi Mat,

It is not difficult to dismantle the input shaft. you just need to remove the drive gear from the end of the input shaft, then the collar with the key simply slides off after knocking out the remains of the shear pin with a slim pin punch.

My leadscrews turned when engaged but stopped when I engaged the half nuts. It was the inherent friction between the collar and driveshaft that was driving the shafts.

Hope that helps,

Best regards and seasons greetings,

Terry

[BazyleParticipant @bazyle]

How did it stop during the accident? Did the pin shear? Is the binding in a particular place along the bed or periodicly as the pinion gets round to the same place (not the handle getting to the same place owing to the geering). I expect the 'gear shaft ' is bent or its mounting hole distorted.

You can find a better manual on the Grizzly website eg g9249 which is teh belt head but the apron is the same.

[Mathew LeeParticipant @mathewlee79288]

Bazyle: I managed to disengage the feed before anything went bang, the binding is periodic with the pinion, so I think you're right that one of the shafts is bent!

How hard is it to disassemble the apron? I guess I'm about to find out!

[BazyleParticipant @bazyle]

Mathew, If you download the G9249 manual since it won't cost anything the shaft I mention is item 336 which is why I called it as they did a gear not pinion. I haven't been able to copy over the diagram like Terry did.

Removing the apron is not so easy as there is a worm gear encircling the feed shaft even if the half nuts come apart enough to not be a problem. I think you need to remove the 3 shafts first which means having some room on the RHS of the lathe.

I've not tried it on this type but have done the following a few times on my Boxford. I run the saddle to the end of the bed, support the leadcrew very carefully pulling it up against a wood block under the bed to keep it true, remove the RH leadscrew support and then it is possible to slide the whole heavy assembly onto a prepared support. Not sure how well this would work on a bigger 3 shaft job.

You could ask on the Yahoo group '12×36 import lathes' which is not as narrow focused as the title suggests and covers all the >10in Eastern lathes.

Edited By Bazyle on 24/12/2012 20:36:17

[Mathew LeeParticipant @mathewlee79288]

I had a go at taking it apart (found my printed manual that came with the machine), the carriage and the apron have locating pins: I was hoping that I could separate the carriage from the apron, then remove the front of the bed, slide the apron to the cut out and be able to remove the pinion without having to actually remove the apron, however I think the locating pins are possibly stopping it. I might be able to make a jig to remove the locating pins as they're tapped, but I think the gear for the cross slide feed sticks out into the carriage.

I thought about disassembling the carriage, but some of the nuts are pretty inaccessible, so it looks like I need to remove the apron.

The worm for the feed is in a bracket held on by 2 screws underneath, but removing the screws didn't enable me to slide the worm away from the apron.

I don't have much clearance on the rhs of the lathe, but I do have the engine hoist I used to get the lathe into position, so I could move the whole lathe: I've been thinking about sliding out the leadscrew to remove those covers as the seriously limit the carriage travel and I clearly should've done it earlier! I think with the leadscrew out of the way, I can possibly get the apron off.

In any case, I'll need to ring Warco for a spare part, so they probably know how to take it apart, I'm sure I'm not the first to have leadscrew cover related damage.

Thanks, Mat

[Mathew LeeParticipant @mathewlee79288]

Bazyle: looks like you were right, after a bit of messing about to get the apron off, turning the handle was still stiff, so punched out the pinion / rod, there's 0.3mm of run out.

Thanks for the help, Mat

[BazyleParticipant @bazyle]

Hey Mat, if you can please take some pictures of the internal gubbins as I've not found any on the web so far.

[Mathew LeeParticipant @mathewlee79288]

 

 

There you go

Edited By Mathew Lee on 02/01/2013 21:58:16

[BazyleParticipant @bazyle]

Thanks, Mat, Interestingly the threading interlock bobin isn't shown on the 9249 parts.diagram. Some other differences so not all designs are exactly alike.

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