# Colchester master cross-feed problem



## Brain Coral

Hello all,

I bought this lathe a couple of years ago and within the last few months, the cross-feed has pretty much stopped working or is very jumpy at best. The lathe is a 1967 gap bed model.

Here's a picture of the lathe...




I have managed to remove the compound, cross-slide and taper attachment from the saddle, as well, I have pulled both the feed rod and leadscrew and then dropped the apron. I realize that it wasn't necessary to remove the compound and cross-slide, but I figured that while I was at it I might as well. I will also remove the saddle and make sure that there aren't any trapped chips underneath.

Here's a couple of pics of the apron assembly...







This last picture is of the apron wormbox...




When engaging the cross-feed, there is a jumpy movement of the wormbox, so I'm suspecting that the problem lies in there. But upon an inspection of the gears and the movements of them, nothing stands out at all. There aren't any missing or chipped teeth, although the pinion gear in the wormbox shows some wear, but not excessive in my opinion.

There are some springs and adjusting screws in the wormbox shaft, but I think that the adjustment is for the kick-out.

Does anyone have any ideas... ?

Cheers... 

Brian


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## hvontres

I am not too familiar with your lathe, but here are a few general questions:

1) Is the long feed still working fine?

2) Is there a lot of play in any of the gears inside the apron? I had to replace a couple bushings on mine, one was the final drive gear from the apron to the cross feed screw.


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## Brain Coral

Hello Henry,

Yes, the long feed works just fine and no, there doesn't seem to be excessive play in the main gear train, so I concentrated my efforts on the cross-feed gear chain. I decided to remove the wormbox assembly from the apron and take that apart.

Here's that picture again...




You can see the pinion gear and shaft at the forefront which meshes with the wormshaft gear. Upon taking the pinion shaft and gear apart, I discovered that on the left end of the shaft, it was scored as was the bearing and seemed to be much looser than on the right end. I'm wondering if this is the culprit and causing a bad gear mesh. The right hand bearing is in real good shape, so I may trade the bearings from left to right and see if that fixes it.

Before I put it all back together, I will see if a friend of mine has those parts as spares from a parts lathe that he has and replace them if I can.

Thanks for the reply... 

Brian


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## dickr

I always thought those were good lathes. I think they use to call them round heads (round head stock)
Good solid machine, coarse can be abused but it looks good from the pics. I'd replace those bearings at both ends. Bearing house should handle that easily. good reason for it to jump. Any other parts that look worn or feel sloppy. Now's the time! You'll have a hardworking lathe if you do. You might look at the drive rod under the screw just to make sure it's solid.  I'd also venture to say that might be the original color.
dickr


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## Brain Coral

Hello dickr,

Yes, that is the original paint. I don't think that it was worked too hard, as the apron had very little in the way of chips in it. It looks like a chip got, caught at some point, between the bearing and shaft. The bearings are a cast iron unit with a triangularly shaped head... not something that a bearing house would have, but my friend is going to have a look at his spare Colchester parts to see if he has a replacement for me.

Thanks for your thoughts... 

Brian


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## Brain Coral

It turns out that my friend didn't have those particular parts, so I worked on the lathe for a couple of hours today, starting by trading the bearings from right to left and then took the front saddle clamp off the saddle to have a look underneath. It was suprisingly very clean, with no sign of scoring, whatsoever. This was also a good opportunity to see if the ball spring oilers were working properly. Only one of them would allow the oil to flow freely. The rest were gummed up with what looked like old grease. I used compressed air to blow them out and followed up with oil and repeat.

Then the saddle went back on with fresh way oil, attached the front saddle clamp and then the rear saddle clamp, adjusting the tension until there was no movement up and down, but it still slid freely on the ways. The saddle went back on next, then the cross-slide assembly slid on from the rear, followed by the croos-slide screw; also fed in from the rear. Next was installing the cross-slide screw keep followed by the cross-slide handwheel, which was adjusted for a smooth but not binding fit.

Next, the taper attachment assembly was pushed onto the locating pins and fastened into place, followed by the outboard bearing and nut. This was also adjusted for a smooth and non-binding revolvement of the screw.

Now came the installation of the compound assembly. 

Next came the lead-screw which was fed through the saddle and on into the change gear box, sliding the leadscrew locking collar, the leadscrew gear, clutch gear, retaining collar and snap ring as I fed it into the gearbox. I found that the feedscrew had to be "not" installed before the leadscrew, in order to line up the gears and splines. Once the retaining collar was adjusted and the setscrew tightened, I then "pinned" the feed rod in place.

Before I tore the lathe down to the point that I did, I was hesitant and outside of my comfort zone.... but having a very detailed parts list and going about it methodically and keeping all of the families of parts labelled and separated into baggies, as well as taking photos of the different stages, it gave me the confidence to delve in. I ended up not having to refer to the photos, but am glad that they were there, just in case.

So, with the lathe back together, I fired it up and put it through all of the speeds and feeds and the cross-feed seems to run like silk. Mind you, that's not under load, so tomorrow I will experiment with some cuts and see how it does.

I hope that this post doesn't come off as me boasting. I thought that it may be of some use to others and by going into some detail, it may inspire others to not be fearful of taking something apart and fixing it.

Thanks for your interest... 

Brian


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## xalky

Brain Coral said:


> I hope that this post doesn't come off as me boasting. I thought that it may be of some use to others and by going into some detail, it may inspire others to not be fearful of taking something apart and fixing it.
> 
> Thanks for your interest...
> 
> Brian


Why would it come off as boasting.... It was broke and you fixed it! Good mechanics do that sort of thing every day. :high5:


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## Brain Coral

Thanks Marcel...


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## metalman133

Hi Brian,
I just read your posting about the colchester. Very interesting, as I have a strip down job to do on mine. I have a square head version but I think these are pretty similar to yours. I need to replace the half nut on mine and have just posted a new thread asking for guidance. You seem to have gone through what I'm about to go through so would you mind if I pick your brains?
Can you tell me exactly what you did to get at the insides of the apron? I don't want to remove more bits than necessary, and I obviously don't want to cause any damage and leave the machine in a worse state that when I started. So a step by step breakdown would be really helpful, if you have the time, also anythings to watch out for such as dowels that can't be seen, bits that will fall to the floor if not supported etc.

Regards,

K


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## Brain Coral

metalman133 said:


> Hi Brian,
> I just read your posting about the colchester. Very interesting, as I have a strip down job to do on mine. I have a square head version but I think these are pretty similar to yours. I need to replace the half nut on mine and have just posted a new thread asking for guidance. You seem to have gone through what I'm about to go through so would you mind if I pick your brains?
> Can you tell me exactly what you did to get at the insides of the apron? I don't want to remove more bits than necessary, and I obviously don't want to cause any damage and leave the machine in a worse state that when I started. So a step by step breakdown would be really helpful, if you have the time, also anythings to watch out for such as dowels that can't be seen, bits that will fall to the floor if not supported etc.
> 
> Regards,
> 
> K



Hello K,

I'd be glad to lend you a hand. I'm heading down to the shop to work on a set of cabinets for a client and will be busy getting them out the door to the spray shop, so I won't be able to reply in any detail until later on this evening.

Cheers... 

Brian


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## Brain Coral

Hello again "K",

I see that someone has responded to your thread regarding this issue. I don't want to steal his thunder, so I will tell you how I removed the apron on mine.

First off, do you have a manual for your lathe and a parts list and diagramatical breakdown? If you do, it will be so much easier for you.

Secondly, on my particular model, the tail-stock end bearing block, for the lead and feed screws are part of the main bed casting. Because of this, there is a little more work involved. If your bearing block on your lathe is a separate part, the job will be less involved.

If your bearing block is an integral part of the main casting, you will have to separate the lead and feed screws from the gear box, release the tail-end collar grub screw on the feed shaft and slide both shafts through the bearing block about halfway. They should be supported with blocking or whatever you can come up with, so that they don't bind in the bearing block and damage the bearings. 

On my lathe, I didn't have to remove the saddle, cross-slide, nor the compound slide to remove the apron.

The first thing to do is to remove the lower gearbox (threading gearbox) cover. 




Sorry for the fuzzy pic. This pic shows the left driving shaft gear. There is a retaining collar with a circlip holding the collar. Remove the circlip and slide the collar to the left. This would be a good time to take a digital picture for your own reference with this cluster of gears and collars. It's not a real complicated arrangement, but I did.

The next two pics show the leadscrew gear and the driving gear coming into mesh. To do so, simply roll the chuck around and manipulate the "metric/neutral/imperial" lever to engage the slots. This is to allow a little more room for the next step.







Now, remove the grub screw from the locking collar at the far right of the gearbox...




Then, unscew one collar at a time until both are entirely clear of the threads on the leadscrew. It may be neccesary to slide the leadscrew out of the gearbox a little to gain enough space to do so. Now, the leadscrew should be free to slide out of the gearbox. Once the leadscrew was clear of the gearbox and supported, I slid a bar through the gears and collars and pulled the whole lot from the gearbox to keep the proper sequence of parts.

Now slide the leadscrew clear of the gearbox and support it.

Next is the feed shaft. There is a pin that binds the feedshaft coupling to the feed shaft. The pin is located outside of the gearbox. Drive this pin out and then slide the feed shaft free of the apron and support it.

In this pic, you can see two locking collars on the outside of the gearbox for the leadscrew. DO NOT fiddle with these locking collars. It is not necessary....  It's been some time since I removed the apron and can't recollect exactly how  got the leadscrew free of the apron. I think that I had to manipulate the leadscrew at the same time that I removed the apron.




Next, are 4 capscrews to remove on the saddle which will detach the apron from the saddle in its entirety. It's a little heavy, but not overly so. It's not a bad idea to have some blocking beneath it to catch it in case it falls.

Now it should be fairly straightforward from here. I'll have to go have a boo at what I wrote and make sure that it makes sense. Feel free to ask any questions. I was a little intimidated when I first did this, but it's really just one part at a time.

Oops... pic 3 and 4 should be reversed...

Best regards... 

Brian


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## Texasgunguy

Hey Brian, I've found that no matter how clean we might think our apron is, the Colchester has its own opinion on that. When I bought mine the cross feed wouldn't work so I tore it down like you did (I didn't have any drawings). Once I got it all torn apart I didn't see anything either. So I just cleaned everything, and reassembled the whole damn thing. Now it works fine. I still get mad thinking about it, I hate not finding out what was wrong.


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## Colchester lathe man

Hi,
If you need any manuals or parts, you can contact me. Frank with FDK 3 Company in Houston.


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## Kiwi

see two locking collars on the outside of the gearbox for the leadscrew. DO NOT fiddle with these locking collars. It is not necessary.... It's been some time since I removed the apron and can't recollect exactly how got the leadscrew free of the apron. I think that I had to manipulate the lead screw at the same time that I removed the apron.




 You have to remove these locking collars to remove the Key  it is a  keyed  bush beside the lock collars the key then goes through bearing and into the lead screw you cannot remove the lead screw without doing so  there is also a threaded collar inside the box with a grub screw and lead plug in it this has to be undone remove the circlip from it's seat remove gear selector lever drive out roll pin pull lever out lift out selector  once thats done engage half nut and wind back the saddle (towards tailstock) this will drag  the lead screw out removing the circlip washer and dog clutch gears as the shaft comes out placing parts  on shelf in order. Wind the leadscrew only half way release the halfnut wind the saddle (towards head stock) till it's clear off the lead screw
The drive shaft undo grub screw in collar at tailstock end then drive out roll pin as in picture above this shaft should just pull out easy  only till its clear of the saddle
to remove the apron support it on the chip tray remove the four cap screws from the saddle drop the apron clear easy slide the lead screw back in and the drive shaft for support and protection 
 Reassembly is just the reverse the locking collars are not done up dead tight just to the point that you feel  the lead screw starts to tighten loose is ok at this point once it's all put back together run it and check the backlash adjust 
accordingly
hope this helps some one you probably have it all sussed by now 
cheers Kiwi


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## Ropata

Hi Kiwi, I too am from the land right under. I hope you still visit these boards because I'm currently in the process of a full tear down and rebuild of this model Colchester and could do with some help. At the moment I'm struggling with removing the tumbler handle shown bottom of your photo above, Is there some kind of shear pin inside the bushing? I noticed a small grub screw on the front.


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## Kiwi

Hi Ropata on brian's #11 post on this page you can see the end of the roll pin stuff a rag under it to catch it if you knock it too far just take a pin punch and tap it out the lever will then pull out then the dog clutch slide will lift out I suggest that taking photos at every stage of the strip down they sure help on re assembly month's latter


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## Ropata

Yeah thanks, I'm looking to pull the lever apart too so have you had the lever apart  from the slide that goes into the gearbox?


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## Kroll

Good morning Brian,stopped by to catch up on what's going on.Read about your problem then solving it which is fantastic and I learned by looking at your pics that I am missing a gear for going from metric/imperial threading.Anyway nothing better than fixing these lathes problems,but once fix correctly they will last the next owners lifetime.Na I having to take a leave of absence from my lathe due to work at work and picking up work at the homestead which I posted over in the Doall section.For now not much time for myself but that's OK


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