2015 POTD Thread Archive

[Round in circles]

Stuart.......... That looks like a steam traction engine fly wheel it's that big .

Come on spill the beans what grade steel how big a duameter is it , what's desired the end size .

Did you turn the internal thread on that lathe with it bolted to a back plate ?
If so roughly how far did you have to have it stand off the back plate ?

I ask because as I was bar boring a parallel 3 x3 x 8 inch block of aluminium freehand that was bolted to and spaced/ stood off the face plate .... suddenly an expensive sounding " clang " & I'd got one dead indexed tip tool .
I turned a bit too deep and caught the headstock shaft even though I thought I'd allowed for the clearance . (It looks I'll have to make my carriage stop a lot sooner than I'd planned )

 

[RJSakowski]

Wow. I would never have guessed that you quench aluminum to anneal it. Doesn't that harden steel?

I don't believe that quenching in the sense of cooling quickly is required for annealing either aluminum or copper. It doesn't hurt and is usually done for sake of expedience.

 

[Round in circles]

Now you have said that I've just had an apprenticeship flash back of nearly 50 yrs ago doing it .
I do believe I gave out bum info earlier in the thread .
Brass is the one you quench in cold water to anneal it not alu or copper ..... You let them air cool

 

[johnnyc14]

I'm in the process of bringing a Ferro branded mill back to health and one of the things that needed attention is the Y axis lead screw and nuts were worn out. The screw turned out to be 32 mm but thread 5 threads per inch in an Acme type thread. Not wanting to mess around trying to find threaded rod like that I bought a 3 foot length of 1.25" 5TPI left hand threaded rod locally. My plan is to machine the rod to match the original and convert the Y axis to an imperial Acme thread size. I ordered 2 bronze nuts from Roton industries and machined them to closely match the originals. Next will be machining the threaded rod. I mounted the threaded rod in the lathe and used it as an arbor to hold the nuts. Since it is left hand thread the nuts wanted to just turn and move away from the chuck when the turning tool touched them so I used one of the old nuts as a jamb nut to hold it from turning on the shaft. Here are some pics to the machining process on the nuts. They are a super nice fit on the rod with almost no detectable backlash.

Here's the original nut and the new ones before and after machining.

 

[Franko]

Nice work, Johnny.

 

[stupoty]

Thread gauge plug for lathe

• stupoty
• Apr 16, 2015

turned between centres so i could check it as i made it for fit in my 3 jaw chuck.

The bolt...

Test fitting backplate

• stupoty
• Apr 16, 2015

moment of truth, and yay :) first time lucky, making the plug guage was a good idea as fliping...

Four jaw chuck on backplate

• stupoty
• Apr 16, 2015

you can see where the threading tool was too pointy and made a trace of e thread in the register...

Internal threading tool in a booring bar

• stupoty
• Apr 16, 2015

Tool made from a used hss centre drill , had to give it a touch with the oil stone once during...

Internal threading tool

• stupoty
• Apr 15, 2015

hss threading tool made from broken centre drill

Backplate

• stupoty
• Apr 14, 2015

New backplate for four jaw chuck

Stuart.......... That looks like a steam traction engine fly wheel it's that big .

Come on spill the beans what grade steel how big a duameter is it , what's desired the end size .

Did you turn the internal thread on that lathe with it bolted to a back plate ?
If so roughly how far did you have to have it stand off the back plate ?

I ask because as I was bar boring a parallel 3 x3 x 8 inch block of aluminium freehand that was bolted to and spaced/ stood off the face plate .... suddenly an expensive sounding " clang " & I'd got one dead indexed tip tool .
I turned a bit too deep and caught the headstock shaft even though I thought I'd allowed for the clearance . (It looks I'll have to make my carriage stop a lot sooner than I'd planned )

I nearly had a panic as i got near full depth threading as the end of the bar is not where the tool is it was getting very close to the chuck jaws (i was up one step on the external jaws) Luckily theirs plenty of depth on the part so I knew i could wind it in before the very end, i should probably have cut an end under cut first.

5tpi threading is taking of a realy wide chip near full depth so i took max 10th a pass after the first 2 or 3.

It's a piece of cast iron bar, i had ordered a face plate casting but they had damage to the size I ordered and offered a piece of bar as substitute. Its about 6.5 inch dia their with its unfinished edge.

I thought i should do to 4 jaw one before the 3jaw as in some ways the rgister pressision is a little less important. All good practice anyway. I've added some more pics, i got it on and managed to missalign 1 of the clearance holes for the chuck, opps some presison fileing will sort that out hopefully chuck body runout and spinle fit seem realy good so im nice and happy with it, i'm trying to decide if i should turn down the edge or if I might not get a slightly bigger 4 jaw somtime soon (ish)

Stuart

 

[Round in circles]

Thanks for the pictures and reply .
I like your thread angle gauge by M&W , I purchased a nice thin steel one a few weeks ago ... Chinese of course , checked it with several indexable tips and found they match very well . So it's about 50/50 as to them being accurate or the misshapen tips fitting a misshapen gauge .

The end set screw that secures the cutting tip in your bar . In my boring bar it sticks out about 10 mm out of the bar , do you have a high tensile steel machine quality Allen key socket headed grub screw on your bar ?

Doing the initial aluminium boring jobby ,I hadn't yet purchased the more stable QCTP , I was using a modified Myford block. I guess that the harmonics showed up a bit and made things just that bit more difficult.
Once I got the QCTP up & running with indexable tips it was like riding in a chauffeur driven Rolls Royce Silver Ghost , till I snagged the indexed tip in the last millimeter or so.

 

[stupoty]

Thanks for the pictures and reply .
I like your thread angle gauge by M&W , I purchased a nice thin steel one a few weeks ago ... Chinese of course , checked it with several indexable tips and found they match very well . So it's about 50/50 as to them being accurate or the misshapen tips fitting a misshapen gauge .

The end set screw that secures the cutting tip in your bar . In my boring bar it sticks out about 10 mm out of the bar , do you have a high tensile steel machine quality Allen key socket headed grub screw on your bar ?

Doing the initial aluminium boring jobby ,I hadn't yet purchased the more stable QCTP , I was using a modified Myford block. I guess that the harmonics showed up a bit and made things just that bit more difficult.
Once I got the QCTP up & running with indexable tips it was like riding in a chauffeur driven Rolls Royce Silver Ghost , till I snagged the indexed tip in the last millimeter or so.

I have a smaller diameter boring bar that a has a ridiculously long screw out the end, i managed to catch it recently, opps.

The grub screw seems quite good quality, not sure if its hardened though.

The thread guage was quite cheep off ebay, i somtimes find the edges not so well finnished or a little thin with the china brand flat guages, i have some that are ok though. I had a very anoying time with cheap bore gauges.

The grind was a little off , I should have put a wider nose flat on it. Works ok though

I did the initial bore with a shaped hss tool not an insert bar keeps it nice and short.

Stuart

 

[Round in circles]

Thanks Stuart ,
The last sentence makes great sense . I hadn't a small enough tool initialy and didn't think to rethink things through when I had the new QCTP and indexable tools in place.

 

[stupoty]

Thanks Stuart ,
The last sentence makes great sense . I hadn't a small enough tool initialy and didn't think to rethink things through when I had the new QCTP and indexable tools in place.

Yeah I need to get some bigger drill bits for starting holes, what ever boring implement i pick up first the hole is about 1mm to small

Stuart