Well after having my mini lathe for a week now I finally got to "make some chips" last night. It may not be pretty and I'm sure I can only get better but here's my first ever part. Yesterday I rescued an old aluminium trolley jack from the scrap when I'd stripped it down I was left with lots of ally plate and steel bars to play with. I thought I would start with having a go at making the crankshaft for Elmers #25 Wobbler that I intend to be my first engine. I turned down a 3/8 rod to just a little bit bigger than the 3/16 diameter that it should be, then took a little bit more off. When I measured it again it was too small, doh!! I'm not too bothered as I'm not happy with the finish of it so I'll have another go tomorrow and see if I can improve. If anyone has any advice for me I would be grateful. The main thing is I'm loving my new hobby and I'm looking forward to many a happy hour in my shed.
First efforts of a UK newbie
- Thread starter Swesson
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Hi Swesson , always good to hear aluminium rather than aluminum lol!.
there are several factors that govern the finish you can achieve when turning , the correct tool shape and speed are probably the most important.
Due to lack of rigidity , these variables are more important on mini and micro lathes than their larger counterparts.
Model engineering is an addictive past time and I am sure you will make rapid progress.
there are several factors that govern the finish you can achieve when turning , the correct tool shape and speed are probably the most important.
Due to lack of rigidity , these variables are more important on mini and micro lathes than their larger counterparts.
Model engineering is an addictive past time and I am sure you will make rapid progress.
AussieJimG
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Welcome Swesson, as long as you are enjoying it, you will get better.
Jim
Jim
WD-40 is useless as a cutting oil for steel , although it is better than nothing with aluminium . I prefer HSS to carbide but only buy genuine Mo-Max or Mushet and use slower speeds than those recommended.
I have not used a mini-lathe , I have a Pultra , but if your lathe is brand new I suggest you check and adjust where necessary the spindle end float clearance and slide way gib screws as these are often any how when leaving Chinese manufacturers , and any play can contribute to poor surface finish.
I have not used a mini-lathe , I have a Pultra , but if your lathe is brand new I suggest you check and adjust where necessary the spindle end float clearance and slide way gib screws as these are often any how when leaving Chinese manufacturers , and any play can contribute to poor surface finish.
canadianhorsepower
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Swesson;. I turned down a 3/8 rod to just a little bit bigger than the 3/16 diameter that it should be, then took a little bit more off. When I measured it again it was too small, doh!!
This was probably cause by to much feed rate when cutting, a tool bit that does not cut properly or some flexing of your part
If anyone has any advice for me I would be grateful.
On aluminium and almost everything else I loved round cutting tool about 1/8 in diameter, 7 degree of rake, and a slow feed rate give a superb finish
as for WD40 as coolant you would be better with water WD40 only contain 10% lubricant and has a flash point of 64 C
The main thing is I'm loving my new hobby and I'm looking forward to many a happy hour in my shed.
that's the most important parts
This was probably cause by to much feed rate when cutting, a tool bit that does not cut properly or some flexing of your part
If anyone has any advice for me I would be grateful.
On aluminium and almost everything else I loved round cutting tool about 1/8 in diameter, 7 degree of rake, and a slow feed rate give a superb finish
as for WD40 as coolant you would be better with water WD40 only contain 10% lubricant and has a flash point of 64 C
The main thing is I'm loving my new hobby and I'm looking forward to many a happy hour in my shed.
that's the most important parts
Philjoe5
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I think you may find that a slower spindle speed and feed rate with cutting oil will improve your finish. I seldom use a spindle speed that's more than 300 rpm for any job, aluminum, bronze, mild steel or cast iron.
Some folks say carbide toolbits need to run at high speeds, but really, they can run at high speeds but will do OK at slower speeds as well. Feed rates play an important part in hobby machines that are lighter compared to their production counterparts.
I've never been disappointed by cutting at slow speeds and slow feed rates, it just takes more time. But patience wins it!
Enjoy the hobby, it will keep getting better,
Cheers,
Phil
Some folks say carbide toolbits need to run at high speeds, but really, they can run at high speeds but will do OK at slower speeds as well. Feed rates play an important part in hobby machines that are lighter compared to their production counterparts.
I've never been disappointed by cutting at slow speeds and slow feed rates, it just takes more time. But patience wins it!
Enjoy the hobby, it will keep getting better,
Cheers,
Phil
Thanks for your great advice guys I'm soaking it all up like a very dry sponge. yesterday I turned my attention to brass and had a go at making the bush that fits into the frame that the the crankshaft goes through. I have to say that I'm very pleased with the results I was expecting brass to turn a little easier than steel and it did. I first drilled a 8mm hole in some ally 1" bar that will be the frame then I turned the brass down to be a press fit into that hole then turned the other side of the bush to 10mm. I drilled a 5mm hole through it for the new crankshaft which I intend to do tonight with cutting oil at a slower speed. I will part off the piece when my new parting tool arrives.
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Hi Swesson,
Try running at 400---500 rpm with the finest feed rate with a sharpened HSS Cutter and apply dobs of Tapmatic Tapping Oil with small paint brush to get a smooth finish.
Cold rolled steel gives good finish. Hot rolled steels are hard to get good finish.
Welcome to HMEM.
I'm not sure which steel it is I'm using. The picture of the steel part I posted was made from a rod that I salvaged from my old trolley jack I think I will try some new 1" steel bar that I have later and see if that turns better. I'm intending to use waste engine oil as cutting fluid I'll see what that's like. I'll keep you all posted.
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Will be delighted with the good results. Most of us have not tried it as it is messy.
There is a new thread on cutting oils by a HMEM member.
Good luck.
There is a new thread on cutting oils by a HMEM member.
Good luck.
Well using waste oil went well, it is a bit messy but never mind. I finished the brass bush that I am delighted with and made a new crankshaft that is a lot better that the first attempt I've even made a start on the crank disc. Heres a piccy of the progress.
With steel I had trouble getting a good surface finish until I started using Tapmatic cutting fluid instead of WD40 or whatever oil; started using the tailstock center to support the work (too much overhang and deflection) and used this lathe tool to remove the last two or three thou of metal;
http://www.gadgetbuilder.com/VerticalShearBit.html
Easy to make and works great on steels of unknown heritage....
Cheers Garry
http://www.gadgetbuilder.com/VerticalShearBit.html
Easy to make and works great on steels of unknown heritage....
Cheers Garry
