My condolences. I naively assumed the front mount selector knobs were a more convenient means of selecting the full range like Norton-like gear changer, more like @John Conroy GH 1440 lathe. I guess not the end of the world but something to be aware of. The Colchester is a Beast!
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King 1440 and Craftex Threading
- Thread starter cuslog
- Start date
Just count the teeth and restamp them. Even if you can figure out the old stamping, I'd still count em.
lucsimoneau
Active Member
Hi all ... just to add to the confusion, maybe someon can explain to me ...
I have an old King Canada 1440B lathe and the front plate has the following information:
But on the side cover where the change gears are, it has this plate on it:
This machine was available with a metric (3mm pitch) lead screw and an imperial model (8 TPI lead screw). From what I have mesured, my lead screw is 7/8 inches in diameter and has a 8 TPI pitch.
Would the side plate be for the metric pitch lead screw with the associated feeds?
If so, that means that I don't have any information for the feed rates associated with the levers and the change gears.
Any insight would be helpful.
Cheers!
I have an old King Canada 1440B lathe and the front plate has the following information:
But on the side cover where the change gears are, it has this plate on it:
This machine was available with a metric (3mm pitch) lead screw and an imperial model (8 TPI lead screw). From what I have mesured, my lead screw is 7/8 inches in diameter and has a 8 TPI pitch.
Would the side plate be for the metric pitch lead screw with the associated feeds?
If so, that means that I don't have any information for the feed rates associated with the levers and the change gears.
Any insight would be helpful.
Cheers!
We have grandkids here for spring break, but I simply could not stand not knowing, so I snuck out to the barn after supper and went over my gearing and did the detailed math. Turns out the internal gears don't affect the numbers the way I assumed they did.
I believe the numbers you inserted into the chart are absolutely correct. Cutting (or obtaining) a 42 and a 36 tooth gear will yield the desired 1.75 at 1-E-A.
That's the good news for @John Conroy. The bad news for me is that I'm gunna have to make myself a spread sheet and figure out what gears I need to do every possible thread there is. I'll never sleep a wink till I do! LMAO!!!
CRAP, I guess I am hopeless.....
Matt-Aburg
Ultra Member
I will get to that.. For the short term, I already threaded the spigot leaving a little bit for die cleanup/ I will be running to KBC for 9 am. I really need to get the housing assembly done. I finished the housing. Spigot is used to true the OD's of the sleeves I roughed on the router when my lathe was down. I need to finish turn some to suit as the bore varied slightly. I am on the home stretch for V3 housings. My to-do list has just grown again finding the rats nest... but at least I found the parts that were missing too...
Big update coming as I close out the Griffith job (this week...) !!
Does it look like this model with the shift selectors on front? Mine is called CT-1440-G but they had different names depending on the re-brander/importer
I don't believe so. The side plate includes the 127 gear so it is the chart that is used with the 8TPI Leade screw to cut metric threads.
A true metric lathe doesn't need the 127 gear. The 127 gear is used with a 100 or 120 gear to convert an 8TPI Screw to the metric equivalent.
I'd guess that if your lathe came with the metric leade screw, it would have entirely different charts attached to it.
Edit - also, the top chart on the side is the same as the front plate.
The manual for my old CT1440G has thread charts for both the 8tpi lead screw and the 3mm one. They call the lead screw a screw leading stick.
Did the lathe come with both "sticks"??? Or was it just a generic manual for both lathes?
Crazy name for it........ LOL!
Usually (hopefully) the manual makes this distinction because the lathes were offered in both IMP/MET. The manual can be pretty sparse & hard to interpret especially if you are new to this. But I have also heard of cases where the metric thread/feed placards were left on IMP lathes or some crazy conversion indicators. Feed I'm usually not too fussed about, but threads have to be bang on.
If you look at the ”front plate”: the 127T/120T is used as an idler to just fill the gap between the 10T and 40T gear. They happen to use the 127T portion of it for convenience. Therefore this is a lathe with an Imperial lead screw cutting Imperial threads. As @lucsimoneau mentions, he measured a 7/8” by 8TPI on the lathe.
The 120/127 transposing gear is required to cut Metric threads on an Imperial lathe. Just like the 120/127 ratio is required on a Metric lathe to cut Imperial threads.
The side chart is for a lathe with a Metric lead screw (3mm pitch) as the 120T/127T transposing gear ratio is actually being used by the input onto the 120T and the output from the 127T portion of the transposing gear. The chart depicts most of the same SAE thread pitches as the front chart. The green boxed items are longitudinal and cross feed speeds in mm / spindle revolution.
So, based on the pictures of the charts on the lathe, NO Metric threads are published. Perhaps the possible ones are listed in the manual?
The 120/127 transposing gear is required to cut Metric threads on an Imperial lathe. Just like the 120/127 ratio is required on a Metric lathe to cut Imperial threads.
The side chart is for a lathe with a Metric lead screw (3mm pitch) as the 120T/127T transposing gear ratio is actually being used by the input onto the 120T and the output from the 127T portion of the transposing gear. The chart depicts most of the same SAE thread pitches as the front chart. The green boxed items are longitudinal and cross feed speeds in mm / spindle revolution.
So, based on the pictures of the charts on the lathe, NO Metric threads are published. Perhaps the possible ones are listed in the manual?
Yup. Pretty sure its the same as mine which is same as as @John Conroy prior lathe
I'd have to check but I think mine does have the metric threading placard mounted on the lathe presuming the 8TPI leadscrew & included gears. Excerpt is from the manual. I can send a PDF copy if it helps
I'd have to check but I think mine does have the metric threading placard mounted on the lathe presuming the 8TPI leadscrew & included gears. Excerpt is from the manual. I can send a PDF copy if it helps
Duh..... Of course you are right! No idea why I thought metric lathes don't need the 127.
lucsimoneau
Active Member
Ju
Just to mention that the front plate top gear is a 40T gear - there is a spot on the photo
lucsimoneau
Active Member
Does this mean that I need to build a spreedsheet to find the correct feeds with my imperial lead screw?Ju
Just to mention that the front plate top gear is a 40T gear - there is a spot on the photo
No. You don't need a spreadsheet. The 40 tooth on the plate graphic is just an example. The charts show the required setups.
Sometimes it helps to do the spreadsheet though because the charts don't always show all possibilities. @PeterT mentioned this oddity earlier in the thread.
lucsimoneau
Active Member
I'm talking about the linear feeds, not the threading. The only available information is on the side plate with the metric values specified.
It's just metric info. Easy to convert. If you need an Imperial chart for convenience, it's an easy spreadsheet to make.
lucsimoneau
Active Member
My questionning is that the side plate chart uses the 120T/127T gear while the front chart just uses the 127T gear as an idler. Will this influence the feed rates obtained on the carriage?
So if I put my levers in the E1 position, the longitudinal feed on the plate states 0.134mm (0.0053 in). Would the use of the 127 idler gear in the inch configuration yeild the same feed?
Ah, your question wasn't clear to me before.
Yes, it matters. At least it does on my lathe. That's the exact issue @PeterT and I were suggesting to @cuslog. Your charts will be wrong for your use if you use a different gear configuration.
However, it won't matter if both the input and output are on the same gear. In this instance the 127 is just an idler gear. Idler gears don't affect the ratio.