Hello and a part-built blowfly

[Jim]

As Roger says those gauges are useful to the point of being essential for thread cutting on the lathe.

As you know with the diamond cutter's sharpening jig you can also use it to grind a very accurate profile thread cutting tool. When I need to, I cut all my threads using the diamond tool holder and the modified cutter.

It's a personal thing but while I have tipped tooling I rarely use it as I find the 'diamond' cutter does an excellent job due I'm sure to to being able to always sharpen it to the correct profile using the jig, essential for a fumble fingers like me.

[Lisa]

All right, you've both twisted my arm and I've just bought one of those gauges.

When I did threadcutting on dad's old big lathe I used the diamond holder and grinding jig; it makes things easy.

Also, for those who think the vertical tool might slip with a big cut, the deepest cut I've taken with a diamond holder was 3mm (6mm off the diameter) in mild steel, there was no issue whatsoever.

Random anecdote:
In the early years of commercial running, dad got in with a large amusement ride company who were quite thrilled to have a steam train ride on the books. The owner of the company was a fitter and turner by trade, having done his apprenticeship before taking on the family business. He was quite delighted by the little Taig lathe and used to drop by regularly for tea, sharing tips and would spend a bit of time 'perfecting' the lathe tools with a stone. Dad said he never noticed any difference before and after.
One tip though was getting tools on centre height:
Hold a ruler vertically and flat against the side of some round stock in the chuck, nip the cross slide in so the tool just grips the ruler, then check with a square; if the ruler's vertical then the tools at the right height, otherwise it'll lean.

[Lisa]

I decided to ignore the thickness for the moment, and get the crossheads fully squared up and machined to the right length and height.
So far, one done, one to go:

The axlebox casting I'm using is tapered, so you can clearly see the rough spot of the finished one where it gets too small; this will all get cut off anyway, so doesn't matter as the bit I need is the right size.

[Jim]

Nov 27, 2016 12:32:56 GMT Lisa said:

Random anecdote:
In the early years of commercial running, dad got in with a large amusement ride company who were quite thrilled to have a steam train ride on the books. The owner of the company was a fitter and turner by trade, having done his apprenticeship before taking on the family business. He was quite delighted by the little Taig lathe and used to drop by regularly for tea, sharing tips and would spend a bit of time 'perfecting' the lathe tools with a stone. Dad said he never noticed any difference before and after.
One tip though was getting tools on centre height:
Hold a ruler vertically and flat against the side of some round stock in the chuck, nip the cross slide in so the tool just grips the ruler, then check with a square; if the ruler's vertical then the tools at the right height, otherwise it'll lean.

You can use a similar method for lining up the centre of the rotary table or chuck with the column on a mill. Using two centres, one in the rotary table the other in the column, bring the column down until it will hold a business card or similar between the two points, you the move the feeds until the card is parallel with the table and all is now centred.

Jim.

[Lisa]

A bit more machining on the crossheads, now they just need to be cut down to width.



I also had a bit of a play with the new lathe, though I really don't like the lack of a carriage stop on it; so that's something I'll have to come up with a solution for. On the plus side though, I finally found out how to change the angle of the compound slide; the slide has to be wound out till the thread disengages in order to uncover two socket head bolts which clamp it in position.

[jon38r80]

Lisa
Had the same concern about a stop for the saddle on my lathe , looking for inspiration I came across this website which has a couple of simple elegant solutions for the type of lathe bed your lathe probably has.
www.micro-machine-shop.com/cross_slide_compound_carriage_gears.htm#Adjustable_Carriage_Stops

[Roger]

Hi Lisa,
Here's another option that's reasonably cheap and would have a far bigger impact than a simple stop. I don't have a stop on the lathe, you don't need one if you can measure where the tool is. I usually face off the end and then set that as zero for the rest of the job. If I switch tools, I gently touch the end and zero the reading, or preset it to the thickness of the parting blade. Ok, you can't do that last operation the same way if you can only zero the count, but you can still move it the thickness of the blade and click zero.

[Lisa]

Thanks, that's quite a brilliant little design, certainly simpler than any of the ideas I've had so far.

Roger, even with a DRO I'd still want a stop, while it may not be necessary, it has the safety bonus of ensuring one doesn't jam the tool into the chuck!

[Roger]

Dec 1, 2016 10:25:11 GMT Lisa said:

Thanks, that's quite a brilliant little design, certainly simpler than any of the ideas I've had so far.

Roger, even with a DRO I'd still want a stop, while it may not be necessary, it has the safety bonus of ensuring one doesn't jam the tool into the chuck!

Fair enough, but it would tell you how far it's embedded into the chuck 

[johnthepump]

Dec 1, 2016 10:11:08 GMT jon38r80 said:

Lisa
Had the same concern about a stop for the saddle on my lathe , looking for inspiration I came across this website which has a couple of simple elegant solutions for the type of lathe bed your lathe probably has.
www.micro-machine-shop.com/cross_slide_compound_carriage_gears.htm#Adjustable_Carriage_Stops

Hi Lisa,

This is an interesting link, as my MicroMill is based on a Taig mill.

Thanks John.

Perhaps I have thanked the person, so thanks to jon38r80 as well

[Roger]

Dec 1, 2016 11:46:58 GMT johnthepump said:

Dec 1, 2016 10:11:08 GMT jon38r80 said:

Lisa
Had the same concern about a stop for the saddle on my lathe , looking for inspiration I came across this website which has a couple of simple elegant solutions for the type of lathe bed your lathe probably has.
www.micro-machine-shop.com/cross_slide_compound_carriage_gears.htm#Adjustable_Carriage_Stops

Hi Lisa,

This is an interesting link, as my MicroMill is based on a Taig mill.

Thanks John.

Perhaps I have thanked the person, so thanks to jon38r80 as well

I guess there's no reason why you couldn't buy a cheap graduated dial, or even engrave one, so as to add measurement to it. I think our old Harrison had something along those lines.

[jon38r80]

The reason I wanted a stop was my lathe is an elderly emco that has no split nut so threading under power towards the chuck is a bit of a gamble. To add the the dimension control that roger suggests and I second as extremely useful. I bought a couple of fibre reinforced plastic caliper said from flea bay ( nice and easy to cut up and drill but work exactly like their stainless brothers) for a couple of quid each from China. Not quite Dro but helpful none the less. Must get round to fixing them properly.

[Roger]

Dec 1, 2016 13:00:36 GMT jon38r80 said:

The reason I wanted a stop was my lathe is an elderly emco that has no split nut so threading under power towards the chuck is a bit of a gamble. To add the the dimension control that roger suggests and I second as extremely useful. I bought a couple of fibre reinforced plastic caliper said from flea bay ( nice and easy to cut up and drill but work exactly like their stainless brothers) for a couple of quid each from China. Not quite Dro but helpful none the less. Must get round to fixing them properly.

Hi Jon,
I always set a zero DRO position at the end of the thread and stop about half a turn or so away from that. I then pull the chuck by hand over the last part until it reads zero. I don't like the idea of trying to stop dead at the end of a cut. I never disengage the half nuts, I think that's adding unnecessary risk and inaccuracy. If you leave them engaged, it doesn't matter what the pitch is, you know you're always going to be picking up the right position at the start.

[Jim]

Dec 1, 2016 14:05:35 GMT Roger said:

........I never disengage the half nuts, I think that's adding unnecessary risk and inaccuracy. If you leave them engaged, it doesn't matter what the pitch is, you know you're always going to be picking up the right position at the start.

I agree Roger, as you say you know you'll always pick up the tread at the right start position. A suggestion I've seen and keep meaning to follow up is to make a crank handle to fit into the end of the bore in the chuck shaft to facilitate turning the chuck by hand to cut short threads or to rewind the chuck ready for the next cut.

Another job that should keep me out of doing the garden.

Jim

[Lisa]

Today was relatively cool (forecast 38°C, was 'only' 33°C), and I was able to direct the bit of breeze that was blowing through the workshop; which made it tolerable around dusk.

So I got back to the crossheads, and faced them down to width (plus a bit) in the new lathe. Here's one done to show how much had to come off:

I considered parting them, but ultimately didn't because it's a fairly deep part and I'm still getting a feel for the lathe.

After doing one, I checked the time and decided dinner could wait, so did the other one.

No trick of the light, they are different sizes; I'll finish them accurately to size in the mill.

[joanlluch]

Dec 4, 2016 9:42:00 GMT Lisa said:

Today was relatively cool (forecast 38°C, was 'only' 33°C), and I was able to direct the bit of breeze that was blowing through the workshop; which made it tolerable around dusk.

Hi Lisa, I sympathize with that. We also have such range of temperatures during our late Spring and early Summer. Fortunately, these temperatures tend to come with very dry air, so you can stand them relatively well for the most part. Then in late Summer it rains a lot, so that helps to keep temperatures controlled during that time. I suppose you don't have such a welcome relief provided by intense rains during the hottest season in Ipswich, Australia...

[Lisa]

Joan,
I'm still not sure whether dry or humid is worse; dry tends to hit you like a brick if you have to go outside, while humid feels like you're melting.
Summer is also our wet season, so it's not uncommon to get multiple severe weather warnings in a day; first for the heat, as a lot of elderly people die of heatstroke here in the summer; then for thunderstorms, often with hail (golf ball sized hail stones are not uncommon).
Thus, summer tends to be a hot and dry day, followed by damaging storms in the evening, then 80-95% humidity through the night.
When we're lucky the rain stays long enough to give a few cool days, otherwise the house is air-conditioned, which also acts as a dehumidifier. The workshop, however, is not so lucky, and has an uninsulated iron roof; though some trees planted a few years back are starting to shade it a little.

Then along comes winter, which gets down to -4°C.

The state tourism board used to advertise Queensland as "beautiful one day, perfect the next."

Fortunately, autumn and spring are mostly pleasant.

[joanlluch]

Wow, it's quite surprising that wheather is so similar in both our locations!!. In our case, storm clouds originate from the hot waters of the Mediterranean Sea and travel from East to West, suddenly discharging on rather unpredictable places. And a lot of big hail stones too that can severely damage cars and house roofs. We don't have such extreme winters though. They are mostly sunny with minimum temperatures rarely below 2°C.

[Jim]

We have a very similar climate here in Canberra though much dryer and with lower humidity; fortunately with cooler nights though. Too hot in the workshop at 33C so have been rebuilding the back verandah which is in the shade. A plus to this is that I'm losing weight.

[Lisa]

Well the crossheads are now machined to width, so I've scribed on some guide lines for where the slidebar slot should be, and started milling out the slot.


Starting with a 6mm cutter I'll go down to almost depth, then work on milling the slot accurately to size and position; which will then give me somewhere to position the pin and piston rod holes from.