One of many gear options on my lathe is also 30 on "a" and 60 on "b". It just happens that I had two 60's on mine when I took the photo.
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King 1440 and Craftex Threading
- Thread starter cuslog
- Start date
One of many gear options on my lathe is also 30 on "a" and 60 on "b". It just happens that I had two 60's on mine when I took the photo.
OK to continue this saga, it only took 2 weeks for the gear cutter to arrive from China. I didn't review the method I used to identify the pitch of the change gears for my lathe but I found all the info online which also got me some conflicting info from different sources. I determined the gear pitch to be module 1.25. For each module there is a set of 8 cutters that will shape the teeth correctly for any gear from the smallest possible to a flat rack with an infinite number of teeth. since I needed to cut a 36 tooth and a 42 tooth gears I needed a number 6 cutter.
I had already made 2 arbors, one for the cutter (22mm bore) and one for the gear blank (19mm bore). They were made from 1" CRS with the large ends turned to 25mm to fit a 24-25mm ER40 collet. I test fit the cutter into one of the 40 tooth gears that came with the lathe and it seems like a good fit.
I installed the 19mm arbor in the Vertex super spacer and indicated the shaft to set it parallel to the mill X axis and also checked that it was parallel to the table horizontally.
Then I set up the footstock to support the end of the arbor. I'm not sure this was 100% necessary but it seemed like a good idea.
To get the cutter on the center line of the gear blank I measured to the top of the blank with my height gage then subtracted half the diameter of the blank and was reassured when it measured 6.100" since I know that is the center height of the Vertex spacer. To get the cutter to that height I measure to the top edge of the cutter and added half it's thickness.
I had conflicting information from 2 sources about the depth of cut to make, Maryland Metrics says for a 1.25 module gear it should be .106" and Evolvement Design says it should be 2.25 X the module pitch which makes .110". So I decided to measure it. I slid one of my 40 tooth gears onto the arbor and moved the Y axis until the tip of a cutter tooth just contacted the top of one of the gear teeth, then set 0 on the DRO and advanced to Y until the tooth bottomed in the gear. I measured .123" on both 40 tooth gears and .120" on the 30 and 32 tooth ones. I decided to use .121" as my cut depth to try and match my existing gears as close as possible.
I wasn't sure how much of the depth I could cut in one pass so I tried .030" then .060" then the entire .121" and with a very slow feed rate it seemed fine to do the full depth in one pass. Spindles speed was set at 215 rpm and feed rate was set just about as slow as it can go on my table power feed. For the 42 tooth gear it was make a pass, turn the indexer 2-9/63 turns and make another pass. The cutter performed well and it seemed to slice through the 4140 gear blanks with little effort.
Here's a short video showing a few cuts.
johnconroy.smugmug.com
The finished gear.
More of the same for the 36 tooth gear except I didn't need the indexing plates, just cut a tooth every 10 degrees.
Tomorrow I'll install them on the lathe and cuts some 1.75mm threads!
I had already made 2 arbors, one for the cutter (22mm bore) and one for the gear blank (19mm bore). They were made from 1" CRS with the large ends turned to 25mm to fit a 24-25mm ER40 collet. I test fit the cutter into one of the 40 tooth gears that came with the lathe and it seems like a good fit.
I installed the 19mm arbor in the Vertex super spacer and indicated the shaft to set it parallel to the mill X axis and also checked that it was parallel to the table horizontally.
Then I set up the footstock to support the end of the arbor. I'm not sure this was 100% necessary but it seemed like a good idea.
To get the cutter on the center line of the gear blank I measured to the top of the blank with my height gage then subtracted half the diameter of the blank and was reassured when it measured 6.100" since I know that is the center height of the Vertex spacer. To get the cutter to that height I measure to the top edge of the cutter and added half it's thickness.
I had conflicting information from 2 sources about the depth of cut to make, Maryland Metrics says for a 1.25 module gear it should be .106" and Evolvement Design says it should be 2.25 X the module pitch which makes .110". So I decided to measure it. I slid one of my 40 tooth gears onto the arbor and moved the Y axis until the tip of a cutter tooth just contacted the top of one of the gear teeth, then set 0 on the DRO and advanced to Y until the tooth bottomed in the gear. I measured .123" on both 40 tooth gears and .120" on the 30 and 32 tooth ones. I decided to use .121" as my cut depth to try and match my existing gears as close as possible.
I wasn't sure how much of the depth I could cut in one pass so I tried .030" then .060" then the entire .121" and with a very slow feed rate it seemed fine to do the full depth in one pass. Spindles speed was set at 215 rpm and feed rate was set just about as slow as it can go on my table power feed. For the 42 tooth gear it was make a pass, turn the indexer 2-9/63 turns and make another pass. The cutter performed well and it seemed to slice through the 4140 gear blanks with little effort.
Here's a short video showing a few cuts.
Metal working projects - John Conroy
This video hosted by SmugMug; your photos and videos look better here.
The finished gear.
More of the same for the 36 tooth gear except I didn't need the indexing plates, just cut a tooth every 10 degrees.
Tomorrow I'll install them on the lathe and cuts some 1.75mm threads!
Looks GREAT John!
Those shipping delays can be a killer!
Hope your 1.75 threads go well!
Well done!
Nice job. Measuring was the smart thing to do. I've noticed different DOC mentioned on spur gears too & never really got to the bottom of the issue. It couldn't be explained by +/- tolerance on the OD & they referenced the correct PD so hard to say. Someone once told me that not everything on the internet is true & I'm starting to wonder...LOL
My old brain gets lost in the maze too easily. I'm not really sure what you mean. I think the surface speed of each tooth as it plows through the steel does matter cuz it affects how it cuts - surface finish, distortion, etc. But the tooth count should make for a much better cutting experience and less worry about feed rate as long as the machine is big enough. IIRC, @John Conroy has a nice big Precision Mathews mill so I think that this is basically a zero issue for him on all counts.
Did I understand correctly?
Just to return for a moment to gears on Susquatch's lathe, what are stock listed gears for imperial threads as per plaques on lathe/ ops manual? Mine is the 30 on "a" shaft and 60 on "b" shaft. This allows cutting most all common pitchs in imperial. Other gears are mostly for cutting metric pitchs. Haven't filled the spaces in on the metric plaques as of yet, appears "best" combo will cut 2 common metric pitchs with out a change.
That looks like some very good gear cutting there John.
That looks like some very good gear cutting there John.
Sorry if I missed it but I didn't see that you cut in a keyway in the ar or for the gear cutter. If not, do you think it would be any better with it?OK to continue this saga, it only took 2 weeks for the gear cutter to arrive from China. I didn't review the method I used to identify the pitch of the change gears for my lathe but I found all the info online which also got me some conflicting info from different sources. I determined the gear pitch to be module 1.25. For each module there is a set of 8 cutters that will shape the teeth correctly for any gear from the smallest possible to a flat rack with an infinite number of teeth. since I needed to cut a 36 tooth and a 42 tooth gears I needed a number 6 cutter.
View attachment 33452
I had already made 2 arbors, one for the cutter (22mm bore) and one for the gear blank (19mm bore). They were made from 1" CRS with the large ends turned to 25mm to fit a 24-25mm ER40 collet. I test fit the cutter into one of the 40 tooth gears that came with the lathe and it seems like a good fit.
I installed the 19mm arbor in the Vertex super spacer and indicated the shaft to set it parallel to the mill X axis and also checked that it was parallel to the table horizontally.
Then I set up the footstock to support the end of the arbor. I'm not sure this was 100% necessary but it seemed like a good idea.
To get the cutter on the center line of the gear blank I measured to the top of the blank with my height gage then subtracted half the diameter of the blank and was reassured when it measured 6.100" since I know that is the center height of the Vertex spacer. To get the cutter to that height I measure to the top edge of the cutter and added half it's thickness.
I had conflicting information from 2 sources about the depth of cut to make, Maryland Metrics says for a 1.25 module gear it should be .106" and Evolvement Design says it should be 2.25 X the module pitch which makes .110". So I decided to measure it. I slid one of my 40 tooth gears onto the arbor and moved the Y axis until the tip of a cutter tooth just contacted the top of one of the gear teeth, then set 0 on the DRO and advanced to Y until the tooth bottomed in the gear. I measured .123" on both 40 tooth gears and .120" on the 30 and 32 tooth ones. I decided to use .121" as my cut depth to try and match my existing gears as close as possible.
I wasn't sure how much of the depth I could cut in one pass so I tried .030" then .060" then the entire .121" and with a very slow feed rate it seemed fine to do the full depth in one pass. Spindles speed was set at 215 rpm and feed rate was set just about as slow as it can go on my table power feed. For the 42 tooth gear it was make a pass, turn the indexer 2-9/63 turns and make another pass. The cutter performed well and it seemed to slice through the 4140 gear blanks with little effort.
Here's a short video showing a few cuts.
Metal working projects - John Conroy
This video hosted by SmugMug; your photos and videos look better here.
The finished gear.
More of the same for the 36 tooth gear except I didn't need the indexing plates, just cut a tooth every 10 degrees.
Tomorrow I'll install them on the lathe and cuts some 1.75mm threads!
Mine is 60/60. But it is far from covering the majority of imperial threads. Murphy lives in my shop someplace. I find that I am ALWAYS swapping gears. Not that I mind. Cutting threads is a labour of love for me. Changing gears, setting up angles, sharpening cutters, etc etc are all a great chance to have some fun.
I have not really looked to see if any of my gears are unique to metric threading other than the 127. I'm still being over-supervised by SWMBO, but I'm pretty sure I can get away with looking at my gears for a while later today. I'll do that and report back later.
I snuck out to my shop @Bandit. Looks like most of the optional gears are there to cover imperial threads. (54, 56, 57, 60 63, 66, 69, & 78). Metric threading only uses 30, 56, 60, and 63.
Odd if you ask me, but there it is!
I should prolly do more metric threading.... NOT! LOL!
Wow, thanks for sneaking out to the shop. Still got snow there? Leaves tracks. Anyway, I am rubbing my head and wondering just how many different gear boxes/setups are on these lathes that are "clones". No, I don't really need to know,LOL. I don't change the gear train on mine for the common imperial threads. But it does appear if I run no reduction from "a" shaft to "b" shaft, maybe able to get 4 to 7 pitch imperial, not that I will need it any time soon. The gears with mine are for cutting metric mostly it seems.
There is one gear set I need to take a look at, a single hub, double gear, have no idea what it is for or where it may go. A picture would help I know, however--. The joys of no reading manual.
Hope you will not have to sneak soon, as it goes, " strut, boy, strut!"
There is one gear set I need to take a look at, a single hub, double gear, have no idea what it is for or where it may go. A picture would help I know, however--. The joys of no reading manual.
Hope you will not have to sneak soon, as it goes, " strut, boy, strut!"
I always marvel at the generic differences between men and women. We are different and I really don't care if the modern wake world insists otherwise.
No, there is no snow here this week. When I look at the snow or the dew or the dust or or or, I see a story that tells the recent past. A bunch of buff feathers and some scuffle marks tells me about a Falcon that nailed a Robin. A flat path with side paddles is a turtle looking for a place to lay eggs, big shoe sized prints in the sand is an old man sneaking out to the shop. My wife sees nothing except snow, grass, and dirt. On the other hand if I put the pepper shaker 1/2 inch out of place, she sees it the instant she walks through the door.
I believe it's our genetic makeup. Women gather and shop, men read signs and hunt. Lots of overlap but that's my take.
No worries. She was gone when I went out there and never knew I was there when she came home.
Nice!
My guess is that it's an intermediate gear from another machine that snuck its way into the set for your lathe and doesn't belong at all.
I mounted the gears and they run nice and smooth and successfully scratch tested 1.75mm threads. Thanks to all the members who helped me get this project done.
Looks like those gears will do a fine job.
The "wake" world, before I left work a few new hires were trying to edgeimacate me about "things". It did not matter what I thought, I was not "aware". Slowly became "aware" one hand was to hold cell phone, now needed 2 people to get one set of Hands. #- sign, was now hash tag, not talking to another person could get me wrote up.
Sorry, better stop now.
The "wake" world, before I left work a few new hires were trying to edgeimacate me about "things". It did not matter what I thought, I was not "aware". Slowly became "aware" one hand was to hold cell phone, now needed 2 people to get one set of Hands. #- sign, was now hash tag, not talking to another person could get me wrote up.
Sorry, better stop now.
I'm pretty sure my gears are module 1.25 too. It's either that or 20 DP. The measurements and numbers don't work out perfect for imperial. I'll prolly go with 1.25 because my lathe was made In China. The gear bore is 1" though so...... Yet another hybrid.
My question is, how did you determine you needed a 20° pressure angle? I can see no visual difference to help me determine this.
All the previous gear cutting I have done was on much bigger gears. This little stuff is bewildering to me. I'm no watch maker. Even under a Magnifier it isn't clear to me what they are.
The best I could come up was this. It's a 40° gauge. I used the biggest gear I have to get as close to a rack as possible. It was hard to take a photo under a magnifying glass, so it's not a perfect picture, but you get the idea.
The math on that particular gear is 78 teeth OD is 3.933" or 99.89mm
(78 + 2) / 3.933 OD = 20.34
Call it 20
99.89 / (78 + 2) = 1.249
(call it 1.25)
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