How Does This Come Apart? QCGB

[David2011]

After many months I finally figured out where this lathe was leaking oil. It didn't leak while running but would discharge 1/2 teaspoon (2.5cc) of oil from the feed rod drive every time I shut it off. After a while that leaves a lot of oil in the chip tray, especially since I mostly work on small items. According to the operation manual the shaft is splined inside the QCGB. I removed the 3 socket head capscrews but there is no sign of movement from the flange either in rotation or by pulling. I put screws in the drive and wrapped some heavy wire around the heads. Yanking on the wire didn't move anything. I suspect that as tight as the screws were and the way they cracked when I broke them loose that they hadn't been removed before. The lathe is a Victor 1340GHE which appears to be a loose clone of the Clausing Colchester 13" 8000 series. This flange and shaft need to come out so I can replace the O-ring that controls oil. Any suggestions?

The manual is not a service manual so the drawing is the best I have.

 

[Ulma Doctor]

If you take a small punch and use one of the countersunk bores, you can tap on the collar to get it to break free. Keep going until you can get a pry bar behind the flange and gently pry it out.

 

[David2011]

Thanks. I tried that last night but will give it another shot. It may just be glued in with 30+ years of hardened oil. I'm tempted to put some heat on it but the lathe is usable as is; I don't want to make it worse. Might try my electric heat gun that will strip paint.

 

[tailstock4]

It might help if you posted more of this parts drawing and the part description of each of the numbers.

You might try lightly tapping on it or prying if you can get under it, but I would strongly caution against using any real force. You just want to see if it moves at all. Also, don’t use heat.

Looking at the drawing you have, it is difficult to tell if or where this shaft terminates. It looks like at least one gear is taper pinned to this shaft. More than likely you are going to have to remove the front cover – and this is a far safer way to go about this.

One other bit of advice, when you use force on a machine tool to disassemble it, you better be very sure that force is the correct solution. Many years ago I received some advice from an older gentleman who had a great deal of experience working on machines. He asked me if I owned a 4 lb. hammer. In response to my answer of “yes”, he told me to throw that SOB as far as I could. Machine tools rarely need more than gentle persuasion to disassemble their parts.

 

[David2011]

It might help if you posted more of this parts drawing and the part description of each of the numbers.

You might try lightly tapping on it or prying if you can get under it, but I would strongly caution against using any real force. You just want to see if it moves at all. Also, don’t use heat.

Looking at the drawing you have, it is difficult to tell if or where this shaft terminates. It looks like at least one gear is taper pinned to this shaft. More than likely you are going to have to remove the front cover – and this is a far safer way to go about this.

One other bit of advice, when you use force on a machine tool to disassemble it, you better be very sure that force is the correct solution. Many years ago I received some advice from an older gentleman who had a great deal of experience working on machines. He asked me if I owned a 4 lb. hammer. In response to my answer of “yes”, he told me to throw that SOB as far as I could. Machine tools rarely need more than gentle persuasion to disassemble their parts.

I'm including scans of the pages as PDFs because there's too much on each page to make good JPG images. Removing the front cover will be a really big deal because the control knobs don't want to come off. I've tried several times in the past including when I painted the machine. I don't want to damage the aluminum plate by prying against it, even with something between it and any tool. I agree that things SHOULD come apart easily but I know that it doesn't always work that way.

The guy that told you to toss the 4 pound hammer has obviously never disassembled a Naval gun that was built in 1912 and was exposed to the oceans of the world until 1948. We ended up using a portable hydraulic ram to take the guns apart.

Back to the problem at hand, if I understand what I've read about the similar Clausing lathes that flange is all that holds the drive in place.

What is the problem with heat from an electric heat gun? Just saying "don't" without a reason doesn't make sense. I've used one many times to disassemble model airplane engines that were stuck together with hardened oil. They're not nearly as robust as a lathe.

When viewing the "Scan of QCGB" everything to the right of part #71 (when rotated to the upright orientation) has been removed in the photo above.

 

[tailstock4]

I’m sure you’re right that he never disassembled a Naval gun of any era. I’m quite sure I haven’t, but it sounds fascinating. Would love to hear more some time. My background was large coal and gas fired power plants, so I understand the need for force on occasion.

My concern with the heat gun wasn’t that it would do any particular harm, but rather it might expand the housing against the feedbox casting making it more difficult to move or pull out.

The drawings refer to part 27 as an overload clutch. It is still unclear to me how the shaft that this is mounted on connects to the shaft and housing that you are trying to pull out. Could be a simple spline. Could be pinned. Hard to say. Most of the ones I’ve worked on would not simply slide out without a little more disconnecting inside. But with your machine, you’re the one with eyes on the problem. I’m sure you’ll figure it out. Good luck.

 

[David2011]

I started some threads some time back on my work for the Battleship Texas restoration. If you search Members Projects for "Battleship" they're easy to find. I haven't posted mush lately; been pretty busy with the actual work as their volunteer machinist.

Part #27 is on the lead screw. I'm working on the feed rod, the shaft below the lead screw, which drives the carriage when not threading.

At this point all I have to go on is that the drawing indicates a splined shaft and the only spring pin (their nomenclature for a roll pin) near that area is for a gear. I'll let is soak with Kroil on it and see what happens. Seems line there is nothing to stop it from rotating once the screws are out and that's what makes me suspicious of solidified oil. Just hoping I don't have to take the front cover off because none of the control knobs want to come off. More Kroil, I guess.

 

[tailstock4]

Sorry about the confusion. I think I got off when I rotated the drawing.

It looks like both the spline shaft and the shaft you are working on turn in bushing (#63) and the gear is pinned to the shaft you’re working on. So I guess the question is whether that gear is small enough in diameter to make it out of the hole that you are pulling the housing out of. If the answer is yes, your problem is solved. But it looks like to me from the drawing that the gear may be a little too large. Sometimes the housing can be pulled by reattaching the feed rod and c-clamping the feed rod at some point on the right side of the apron where the feed rod comes out. The c-clamp becomes a stop to push against. Then use the carriage to pull the housing. I’ve done this with some success with both feed rods and lead screws. Of course your end bracket would have to be removed. Just a thought, but I don't know what your apron looks like.

 

[David2011]

Sorry about the confusion. I think I got off when I rotated the drawing.

It looks like both the spline shaft and the shaft you are working on turn in bushing (#63) and the gear is pinned to the shaft you’re working on. So I guess the question is whether that gear is small enough in diameter to make it out of the hole that you are pulling the housing out of. If the answer is yes, your problem is solved. But it looks like to me from the drawing that the gear may be a little too large. Sometimes the housing can be pulled by reattaching the feed rod and c-clamping the feed rod at some point on the right side of the apron where the feed rod comes out. The c-clamp becomes a stop to push against. Then use the carriage to pull the housing. I’ve done this with some success with both feed rods and lead screws. Of course your end bracket would have to be removed. Just a thought, but I don't know what your apron looks like.

The first thing I did was remove the end bracket and slide all 3 rods out of the way. The flange just needed a few more solid taps and it broke loose. It was, as expected, stuck in place due to hardened residue. The flange pulled out easily with my wire contraption. Unfortunately, you were right about the gear being pinned to the shaft so I had to figure out how to get the front cover off. Fortunately, I found a detail that I had previously overlooked. The 3 black control knobs were held on with 2 set screws each. Once both of the setscrews were removed the knobs came off but I would not say they came off easily. The important thing is that I didn't lose any of the detent balls and springs. The numbered dial of the big round knob was removed to give better access to one of the socket head capscrews but it didn't help. I cut the paint at the seam and the front came cover off without even damaging the gasket. I will apply some Permatex before putting it back on. Another leak would really bite.

The roll pin in the gear was a challenge to get out. It had to be driven out part way, the shaft rotated and the pin pulled with Vise Grips. Seeing how much heavy material had collected in the bottom of the gearbox made having to remove the cover a little easier to swallow.



All I need to do now is find a correct size O-ring and reassemble. The O-ring goes on the shaft somewhere inside where the casting is. Once the pin was out of the gear the shaft came out easily. Once the snap ring was off (visible edge-on against the orange paint) the assembly slid apart easily. The existing O-ring was definitely flattened. It's probably 40 years old.

The manual specs the O-ring size as P22.4 (item 152). Does anyone know what that means? I'm pretty familiar with Imperial sized O-rings but lost on metrics nomenclature. I'm only a few miles from a massive industrial area along the Houston Ship Channel so surely one of the O-ring places over there can help.

I knew that the headstock was leaking when I bought the lathe. The seller didn't even clean the chips packed in oil up and the origin if the first leak was obvious. I only discovered the second leak after fixing the first one. I usually machine dry so the constant presence of oil was a nuisance.

Thanks for all of the excellent answers! Every response had correct information. I am really looking forward to having a dry chip tray.

 

[GHThomas]

The "P" is the O-ring series; the 22 is the ID in mm and the 4 is the cross section (D) in mm.