Possible help with lathe?

[Oliver19619]

Hi there ladies a gentleman, just wondering if anyone could guide me in the right direction, I’ve just got into hobby machining about a year ago, started with a mini lathe, have just possibly downgraded to a 10x22 bench lathe, okay so here is the issue.
Change gears for threading.
Okay so I believe I’m setting the gears correctly however I don’t believe this is the case because the thread pitch isn’t correct I’m aiming for 1.25 as you can see from photos the pitch isn’t correct on the scratch pass, do the drive gears look correct? Not a clue to be honest any help/advice would be greatly appreciated. Thanks

 

[Oliver19619]

Okay little update, these are the actual feed rates, per 1 revolution of the spindle, some appear to add up with the chart whilst others don’t, I’m not sure what’s going on, any help would be greatly appreciated.

 

[chaoticbob]

Hi Oliver. Have you made any progress with sorting this out? It seems pretty mysterious. From your picture there is nothing wrong with the change wheel setup. The only thing we can't see in the pic is the gear on the drive shaft, which is presumably correct and is not intended to be changed.
From the picture of your thread dial indicator it looks like the lathe has a 2mm pitch leadscrew. If it were me, as a starting point, I'd mount the 63/63 wheels, set the gearbox at B3 and check that leadscrew is in 1:1 sync with the chuck. Just a sanity check!

As the lathe seems to have both powered cross feed and sliding (longitudinal) feed there must be a gearbox in the apron. That complicates calculation of the relationship between threading and ordinary turning feed for a particular setup, but given data, it can be done. At the moment I can't understand your data for the sliding feed. You find that your measurements at some settings chime with the chart on the machine, but others don't. I compared 27 of your measurements with the machine chart and found that allowing for the likely margins of error in your measurements, combined with rounding errors on the chart, your measured feed rates are consistently around 2.5 times higher than the rates on the chart. So I don't know what's going on there either!
I'd be interested to hear how this pans out.
Rob.

 

[Oliver19619]

Hi Oliver. Have you made any progress with sorting this out? It seems pretty mysterious. From your picture there is nothing wrong with the change wheel setup. The only thing we can't see in the pic is the gear on the drive shaft, which is presumably correct and is not intended to be changed.
From the picture of your thread dial indicator it looks like the lathe has a 2mm pitch leadscrew. If it were me, as a starting point, I'd mount the 63/63 wheels, set the gearbox at B3 and check that leadscrew is in 1:1 sync with the chuck. Just a sanity check!

As the lathe seems to have both powered cross feed and sliding (longitudinal) feed there must be a gearbox in the apron. That complicates calculation of the relationship between threading and ordinary turning feed for a particular setup, but given data, it can be done. At the moment I can't understand your data for the sliding feed. You find that your measurements at some settings chime with the chart on the machine, but others don't. I compared 27 of your measurements with the machine chart and found that allowing for the likely margins of error in your measurements, combined with rounding errors on the chart, your measured feed rates are consistently around 2.5 times higher than the rates on the chart. So I don't know what's going on there either!
I'd be interested to hear how this pans out.
Rob.

Hi Oliver. Have you made any progress with sorting this out? It seems pretty mysterious. From your picture there is nothing wrong with the change wheel setup. The only thing we can't see in the pic is the gear on the drive shaft, which is presumably correct and is not intended to be changed.
From the picture of your thread dial indicator it looks like the lathe has a 2mm pitch leadscrew. If it were me, as a starting point, I'd mount the 63/63 wheels, set the gearbox at B3 and check that leadscrew is in 1:1 sync with the chuck. Just a sanity check!

As the lathe seems to have both powered cross feed and sliding (longitudinal) feed there must be a gearbox in the apron. That complicates calculation of the relationship between threading and ordinary turning feed for a particular setup, but given data, it can be done. At the moment I can't understand your data for the sliding feed. You find that your measurements at some settings chime with the chart on the machine, but others don't. I compared 27 of your measurements with the machine chart and found that allowing for the likely margins of error in your measurements, combined with rounding errors on the chart, your measured feed rates are consistently around 2.5 times higher than the rates on the chart. So I don't know what's going on there either!
I'd be interested to hear how this pans out.
Rob.

Hi Oliver. Have you made any progress with sorting this out? It seems pretty mysterious. From your picture there is nothing wrong with the change wheel setup. The only thing we can't see in the pic is the gear on the drive shaft, which is presumably correct and is not intended to be changed.
From the picture of your thread dial indicator it looks like the lathe has a 2mm pitch leadscrew. If it were me, as a starting point, I'd mount the 63/63 wheels, set the gearbox at B3 and check that leadscrew is in 1:1 sync with the chuck. Just a sanity check!

As the lathe seems to have both powered cross feed and sliding (longitudinal) feed there must be a gearbox in the apron. That complicates calculation of the relationship between threading and ordinary turning feed for a particular setup, but given data, it can be done. At the moment I can't understand your data for the sliding feed. You find that your measurements at some settings chime with the chart on the machine, but others don't. I compared 27 of your measurements with the machine chart and found that allowing for the likely margins of error in your measurements, combined with rounding errors on the chart, your measured feed rates are consistently around 2.5 times higher than the rates on the chart. So I don't know what's going on there either!
I'd be interested to hear how this pans out.
Rob.

hi there bud yes all sorted out now, not sure how I managed it but I seem to have created 2 threads with the same title not sure if you can possibly click on my name and see the other one, on there has all the information as to how it was sorted, bit of luck/few days of messing about in my spare time as well as friendly advice on here. Thanks