Andrew, from here it looks like your parting tool may be a tad under the center line of the chuck. If it is it would cause the tool to grab the stock rather than shear it. What I have found that works well for me is to use the parting tool to face off some stock and work up to the point where it takes off the little tip that is left if a tool is too low. If the tool is too high and you are using an insert, the tool will rub to the point where there is so much pressure that it shatters the insert. (Yes, I have learned this lesson the hard way.) Thanks for sharing your successes but more importantly your struggles with us.
Dear Andrew, Really enjoy your machining with mistakes. As a time served machinist one must bear in mind these are all one off's. Of course the first off is wrong. You reset your machine and practise and get it right then continue to make a larger batch. Production work teaches you this. After many years you get the first off right and enter the world of skilled men. I just did about eight years before life took another turn and I return forty years later making mistakes everyday. It is what makes this pastime hobby trade call it what you will so fascinating. You know what your doing and thank you for putting up your channel. I for one think you are doing a great job. I am off tomorrow to the Stuart foundry to buy my S50. It is an old timers dream. Engines in dusty cabinets with a dog on the couch and stuff lying about. Yes I am no modern man. Analogue all the way. God bless.
Hi Andrew. Many thanks for the support and encouragement! Yeah I agree, it's a fascinating hobby and it keeps the old brain active. Enjoy your visit to Stuart and I hope the S50 turns out well. All the best. Andrew
I think Tubalcain recommend 3/16 r. from the hole as that = 6/32 and very close to 13/64 (0.203125) which is half of the width of that small arc, to get you close enough to eyeball where to scribe a mark from each edge, simplifying locating the feature. to be more precise would be some very accurate measurement which takes away from modelling and wholly in the realm of experienced machining technique and tools. you did fine! maybe it will have a harmonic vibration at a certain rpm because it's not super precision, but is any hobbyist's model utterly perfect?
Thanks for the suggestion Timothy. I did later remake it and made a far better job of it. Since then I've purchased a jeweller's saw. They are great for cutting fine slots and good for cutting bolts to length as they don't damage the threads. Take care! Andrew
Yes I agree and use one all the time particularly for cutting small studding and screws. The blades are a bit fragile but as you say, the burrs they raise are minimal. Thanks Tim
Use heavy high sulpher thread cutting oil for parting and flood it. The mini lathe isn't stiff enough to part steel very well. you have way too much over hang on your compound, pull it back until the top and bottom castings are even and lock it down. too much over hang on your tool holder allowing it to spring. If you can use the stock 4 way tool holder it will give you a lot more ridged setup than the quick change, especially with the parting toolholder hanging that much farther out. use the narrowest parting tool available. Those type of inserts should never need honing. Parting off sucks no matter what you do.
Thanks for the tips Ross. I think that this was one of my earlier attempts at parting off and it wasn't a great experience. I agree that the mini lathe isn't great when it comes to parting off, but locking everything down certainly helps. I have now reverted to using a thin HSS tool, which works reasonably well.
Hey Andrew: Forgot to add: What size slot width was your crank pin head? Missed that . Have you tried this? Collet block in vise ----- USE A 'JEWELERS SLITTING SAW ' WITH MATCHING ARBER OR USE VERTICAL ROT./TABLE . THE S..SAWS YOU CAN GET ALL SORTS OF SIZES FOR SCREW SLOT CUTTING. WE USE THEM HERE FOR MAKING 'EXACT' SIZE SLOT SCREWS FOR GUNSMITHING WITH HALLOW GROUND SCREWDRIVERS SO DON'T DAMAGE SLOT. HAVE YOU ALSO TRIED A HIGH SPEED STEEL PARTING OFF BLADE ----- THAT MIGHT HELP ALSO IN STEEL---- LESS PRESSURE TO CUT CHEERS MIKE
Andrew if you can’t recess the stud thread, you can put a recess in the internal thread with a slightly bigger drill, good videos, from one Yorkshire man to an other sithee.
HI ANDREW: I KIND OF SUSPECTED THAT---- IT SEEMED IN THE VIDEO'S YOU AWAYS HAD JUST GOTTEN SOMETHING NEW. THAT'S WHAT MAKES MODEL ENGINEERING PART OF THE FUN. CHEERS MIKE @@learningturningmetal
Hi Andy. I'm certainly determined to make a better one next time. Just trying to work out how to tackle the conrod. 🤔 It looks a little complicated. Cheers Andrew
If you can get a HSS P type parting blade .040 wide you will find it parts better since it's removing less material than the insert so less force on the lathe, easy to sharpen and hone and can be used to cut the thread relief.... www.amazon.com/CUT-P1N-P-Type-Cut-Off-Blade-Speed/dp/B00P0347B0
Hi Dave - I was starting to think on the same lines re HSS. Many thanks for the link. I will see if I can get something similar in the UK. I didn't have great success initially parting with HSS when I first started out, but I think I can put it down to poor lathe setup rather than the tool. I maybe need to get to grips with HSS tool sharpening too. Cheers Andrew
Hi Dave. Ha ha! Been on hols and been mulling over how to turn my first taper for the conrod. Just this minute finished it and now working out how to fix it to the rotary table to put a radius on both ends. Hope to get part 7 up soon! Thanks for the interest. All the best. Andrew
* IMPORTANT * IMPORTANT *
Please do not follow my bad working practice at 10:18.
Keep safe!
Cheers.
Andrew
Andrew, from here it looks like your parting tool may be a tad under the center line of the chuck. If it is it would cause the tool to grab the stock rather than shear it. What I have found that works well for me is to use the parting tool to face off some stock and work up to the point where it takes off the little tip that is left if a tool is too low. If the tool is too high and you are using an insert, the tool will rub to the point where there is so much pressure that it shatters the insert. (Yes, I have learned this lesson the hard way.)
Thanks for sharing your successes but more importantly your struggles with us.
Dear Andrew, Really enjoy your machining with mistakes. As a time served machinist one must bear in mind these are all one off's. Of course the first off
is wrong. You reset your machine and practise and get it right then continue to make a larger batch. Production work teaches you this. After many years you get the first off right and enter the world of skilled men. I just did about eight years before life took another turn and I return forty years later making mistakes everyday. It is what makes this pastime hobby trade call it what you will so fascinating. You know what your doing and thank you for putting up your channel. I for one think you are doing a great job. I am off tomorrow to the Stuart foundry to buy my S50. It is an old timers dream. Engines in dusty cabinets with a dog on the couch and stuff lying about. Yes I am no modern man. Analogue all the way. God bless.
Hi Andrew. Many thanks for the support and encouragement! Yeah I agree, it's a fascinating hobby and it keeps the old brain active. Enjoy your visit to Stuart and I hope the S50 turns out well.
All the best.
Andrew
Sometimes, I get better results parting off with carbide inserts by using a more aggressive in-feed rate. Go for it!
I think Tubalcain recommend 3/16 r. from the hole as that = 6/32 and very close to 13/64 (0.203125) which is half of the width of that small arc, to get you close enough to eyeball where to scribe a mark from each edge, simplifying locating the feature. to be more precise would be some very accurate measurement which takes away from modelling and wholly in the realm of experienced machining technique and tools.
you did fine! maybe it will have a harmonic vibration at a certain rpm because it's not super precision, but is any hobbyist's model utterly perfect?
Great series Andrew, I look forward to following along with your build :-)
Thanks Peter - no pressure there then!
All the best. Andrew
3:00 Use a “centre drill” first to get the location established. They’re only a few quid and will ease the life of your twist drills. :-)
Awesome. I'm learning right along with you
Great! - I'm glad you found it interesting.
All the best.
Andrew
sweet Andrew you are an inspiration....keep up the good work that you are doing.
Thanks Ray. Much appreciated.
All the best.
Andrew
Great video Andrew, you do awesome work.
Thanks Greg. I'm slowly getting there.
Cheers
Andrew
Hi Andrew - How about a couple of spanner flats on the head of the crank pin instead of a slot on the head. keep up the good work.
Thanks for the suggestion Timothy. I did later remake it and made a far better job of it. Since then I've purchased a jeweller's saw. They are great for cutting fine slots and good for cutting bolts to length as they don't damage the threads.
Take care!
Andrew
Yes I agree and use one all the time particularly for cutting small studding and screws. The blades are a bit fragile but as you say, the burrs they raise are minimal.
Thanks
Tim
Use heavy high sulpher thread cutting oil for parting and flood it.
The mini lathe isn't stiff enough to part steel very well.
you have way too much over hang on your compound, pull it back until the top and bottom castings are even and lock it down.
too much over hang on your tool holder allowing it to spring. If you can use the stock 4 way tool holder it will give you a lot more ridged setup than the quick change, especially with the parting toolholder hanging that much farther out.
use the narrowest parting tool available.
Those type of inserts should never need honing.
Parting off sucks no matter what you do.
Thanks for the tips Ross. I think that this was one of my earlier attempts at parting off and it wasn't a great experience. I agree that the mini lathe isn't great when it comes to parting off, but locking everything down certainly helps. I have now reverted to using a thin HSS tool, which works reasonably well.
Hey Andrew: Forgot to add: What size slot width was your crank pin head? Missed that . Have you tried this? Collet block in vise ----- USE A 'JEWELERS SLITTING SAW ' WITH MATCHING ARBER OR USE VERTICAL ROT./TABLE . THE S..SAWS YOU CAN GET ALL SORTS OF SIZES FOR SCREW SLOT CUTTING. WE USE THEM HERE FOR MAKING 'EXACT' SIZE SLOT SCREWS FOR GUNSMITHING WITH HALLOW GROUND SCREWDRIVERS SO DON'T DAMAGE SLOT.
HAVE YOU ALSO TRIED A HIGH SPEED STEEL PARTING OFF BLADE ----- THAT MIGHT HELP ALSO IN STEEL---- LESS PRESSURE TO CUT
CHEERS MIKE
Hi Mike
The drawing suggests 1/32" so I guess it would be in that ball park.
Cheers
Andrew
You need a small slitting saw to put the slot in the screw.
Andrew if you can’t recess the stud thread, you can put a recess in the internal thread with a slightly bigger drill, good videos, from one Yorkshire man to an other sithee.
Ee ba gum. Thanks for the tip Tony. 👍
Lose the plastic guard over the chuck. Throw away the rear chip shield as well, You will get so much better access for measuring and set up.
Thanks Ross - several months later I did remove the guard cover and I agree it makes a massive difference.
Cheers
Andrew
10:18 Christ, mate, you need those dear fingers! If that blade catches, the machine will push it through your hands in a blink.
Blimey - Silly me. I didn't realise at the time! Thanks for the advice. I think I need to increase my personal injury insurance!
Cheers
Andrew
Lesson learnt!
HI ANDREW; I'M SURE YOU ARE AWARE OF CHRONOS BUT THEY HAVE EVERYTHING YOU NEED IF YOU WANT TOO. GO THERE MIKE
Hi Mike - yeah I'm a regular customer 🤣
HI ANDREW: I KIND OF SUSPECTED THAT---- IT SEEMED IN THE VIDEO'S YOU AWAYS HAD JUST GOTTEN SOMETHING NEW. THAT'S WHAT MAKES MODEL ENGINEERING PART OF THE FUN. CHEERS MIKE @@learningturningmetal
The next time you make that screw you'll make it in half the time and it'll be twice as good
Hi Andy. I'm certainly determined to make a better one next time. Just trying to work out how to tackle the conrod. 🤔 It looks a little complicated.
Cheers
Andrew
Use WD40 when working aluminum.
👍👍👍👍👍🇬🇧...
Cheers mate!
:)
If you can get a HSS P type parting blade .040 wide you will find it parts better since it's removing less material than the insert so less force on the lathe, easy to sharpen and hone and can be used to cut the thread relief.... www.amazon.com/CUT-P1N-P-Type-Cut-Off-Blade-Speed/dp/B00P0347B0
Hi Dave - I was starting to think on the same lines re HSS. Many thanks for the link. I will see if I can get something similar in the UK. I didn't have great success initially parting with HSS when I first started out, but I think I can put it down to poor lathe setup rather than the tool. I maybe need to get to grips with HSS tool sharpening too.
Cheers
Andrew
Ha ha re your first comment!
Part 7? Have you been busy or did you get stuck on how to do something? LOL
Hi Dave. Ha ha! Been on hols and been mulling over how to turn my first taper for the conrod. Just this minute finished it and now working out how to fix it to the rotary table to put a radius on both ends. Hope to get part 7 up soon! Thanks for the interest.
All the best.
Andrew