OT from How do I?? "Mini lathe transmission replacement"

[PekkaNF]

Pekka,

I will not argue over this issue, if you want to ignore many years of design and machining experience, and if you think you are better than the original machine designer, you just go ahead and do whatever you want.

There is a great difference between doing minor mods to a machine to get it to work better, and what you are trying to do, which is to take it beyond it's already designed limitations.

I would suggest that you don't ever post anything on here ever again about a lathe you own either breaking or burning out, as you will get no sympathy from this quarter, in fact, I will sit back and laugh at your machines' demise.

Bogs

Didn't want to hijack the thread soo here it goes:

1) My intention was not to undemine anybodys experience or skills on this board

2) I'm bit new here, I probably should have used longer time lurking here

3) If I get kicked out here: No problems and hard feelings.

4) I value experience very high. I value Bogs input here and also on some other forums. It was his article that led me here after all!

5) I see bad design all the time. Many people would be surpriced how much there is bad design. It's not always engineering: Once I was on one ocasion where one car designed triumphed when he went against engineers and against sales department to make it look more agresive and more of his vision.

and lastly: Everybody is responsible for his own actions. If I'm inspired to do something that looked like a good idea and it goes KABOOM: you guys are first ones to hear from it! But it is because I would need sympathy (well maybe just a little). If I live to tell the tale I would like someone learn from my mistakes. I have learned a lot. Sometimes I'm inspired on someones success and sometimes I'll take something more seriously if someone fails.

Are we cool?

Pekka

[spuddevans]

I'm just going to repeat what I posted up in the original thread,

I would suggest that you don't ever post anything on here ever again about a lathe you own either breaking or burning out .......

I think that it is not in keeping with the general atmosphere of this forum to discourage anyone from posting about their experiences and tools, even when they might have caused the problem themselves by ignoring advice given.



That being said, Pekka, it might be wise to listen to the advice being offered from many experienced engineers, the last thing we want to see is a picture of you, or anyone for that matter, having recieved injuries because a machine was pushed beyond its capabillities and let go.


We all want to be the one who pushes the "envelope" further, to "boldly go where no-one's been before", but let's do it safely.

1) My intention was not to undemine anybodys experience or skills on this board

I dont think that your comments were taken that way, I think that there was just concern being expressed over the potential consequences of what you seemed to be suggesting.

2) I'm bit new here, I probably should have used longer time lurking here

As a forum, we have always tried to encourage members both old and new to post up their questions, thoughts and comments. Like any internet forum, the written word is often not as clear as the spoken word (add to that the potential misunderstandings that come with many different languages), so often things can be taken not as they were intended.

3) If I get kicked out here: No problems and hard feelings.

I dont think you are going to be "Kicked out"

4) I value experience very high. I value Bogs input here and also on some other forums. It was his article that led me here after all!

5) I see bad design all the time. Many people would be surpriced how much there is bad design. It's not always engineering: Once I was on one ocasion where one car designed triumphed when he went against engineers and against sales department to make it look more agresive and more of his vision.


and lastly: Everybody is responsible for his own actions. If I'm inspired to do something that looked like a good idea and it goes KABOOM: you guys are first ones to hear from it! But it is because I would need sympathy (well maybe just a little). If I live to tell the tale I would like someone learn from my mistakes. I have learned a lot. Sometimes I'm inspired on someones success and sometimes I'll take something more seriously if someone fails.

It is very true that each person is responsible for their own actions, but you have to realise that this is a public forum, and we have to be mindful that many more people read these posts than comment on them. That's probably why a number have responded a bit negetively to your post, they are mindful that some may read things on a forum and then take that as gospel truth and could potentially injure themselves implimenting such ideas.


So please dont take all this as a personal attack on you or your ideas, it is meant purely as a cautionary note to be careful when you want to push machinery beyond it's originally designed specs.

Are we cool?

How could we be anything other than cool, cos we are all part of Madmodders, the coolest place on the net  


Tim

[PekkaNF]

Thanks Tim,

I understand and agree most of your post. I read it and appreciate you effort to explain.

I'm afraid I'll get here even more deeper on this one, but -  In spirit of your answer: I feel to ask on one detail. If I get it right your take on this one is all about machine safety?

This concern about this exact case is the one that I don't quite get. I see here all kind of techniques suggested and used and never seen text
peppered with warnings.

To my understanding on the original post question was to keep the original motor and the lathe and to replace the gear train with belt drive. No mention of hooking the lathe at the rear end of V8.

Then I butt in and blurted out on what I have been thinking of doing with automotive parts. And I'm all ready miffed about the drama I got myself in and strangely have need to explain myself.

Putting this to minilathe context: Automotive parts are manufactured under rather strict standards and rated to several kilowats and some serious rpm compared to the minilathe. My question is: What is this danger that my answer seems to suggest?

Exceeding the lathe evnelope or maximum ratings? I'm unaware what are design limits of this particular lathe. I have seen only machine cards of industrial production machines. The hobby lathe etc. I have bought are not furnished with this information. Maybe minilathe has that information. I bought a little time ago a pneumatic percusion drill (Makita) the manual had pretty good spesification on what size drills to use on different material and what performance to expect.

I got salvo fired at me, here is my spin:

I'm an electical engineer and I have been working most of my adult life on a company that makes manufacturing machinery and most of them exceeds big time: volume, size, weight, power demand and also unfortunately the value of house I'm living in. This explains why I can think of several problems when a person that is not professional electrician installs VFD. Staring from lethal voltages, risk of fire, interference to the possible bypass of safety features and original lathe controls and to the possibility of bursting the cast iron chuck (should wrong mechanical speed selected AND ramping motor over 100& of speed). Not to mention what it would do original lathe bearings. One thing that probably is discussed here is dangers of running motor too low. Not only to bearings, but also a small (and retofit) motors are not fitted with temperature switch or sensor and hardly ever they are connected to VFD. What happens if fan cooled motor is spun slow (usually to turn relatively large diameter billet)?

I did not suggest of using belts here, but suggested on having a look on automotive parts. How is this different of using steel replacement gears? And we are talking here about minilathe.

I have been writing safety instructions last two months and I'm full of newish EU safety standards. It might go a little way of explaining why I'm a little cranky about safety related issues now.  If I need an mechanical/electrical/hydraulic/pneumatic view on stuff I can talk to design engineers on coffee break and ask. Sometimes I even learn a bit.

I take my work very seriously. My hobby takes my mind off the work, because it demands 100% concentration. As we all should know power tools are very unforgiving. I never go garage mad or tired. As you see I'm here. Wondering if it is any good to post this respond.

Anyway, my take on safety and now I'm off to figure how to hook a mighty big QCTP on lathe.

Thank you for listening,
Pekka

[spuddevans]

Hi Pekka,

If I get it right your take on this one is all about machine safety?

I didnt mean to give that impression, the main number one concern I have is Personal Safety, if anyone wants to risk spoiling their machines that is entirely up to them and their wallet

This concern about this exact case is the one that I don't quite get. I see here all kind of techniques suggested and used and never seen text
peppered with warnings.

To my understanding on the original post question was to keep the original motor and the lathe and to replace the gear train with belt drive. No mention of hooking the lathe at the rear end of V8.

Then I butt in and blurted out on what I have been thinking of doing with automotive parts. And I'm all ready miffed about the drama I got myself in and strangely have need to explain myself.

Putting this to minilathe context: Automotive parts are manufactured under rather strict standards and rated to several kilowats and some serious rpm compared to the minilathe. My question is: What is this danger that my answer seems to suggest?

Exceeding the lathe evnelope or maximum ratings? I'm unaware what are design limits of this particular lathe. I have seen only machine cards of industrial production machines. The hobby lathe etc. I have bought are not furnished with this information. Maybe minilathe has that information. I bought a little time ago a pneumatic percusion drill (Makita) the manual had pretty good spesification on what size drills to use on different material and what performance to expect.

Your comments about using a belt drive are valid, and the newer version of the mini-lathe comes with a belt drive. But I think the parts in your post that maybe sparked off a few of the comments were -

If you can chuck 7" billet on 7" lathe and there is no indication (maybe there is on the user manual?) that you can only turn e.g. 2" of free maching steel, 3" aluminium with 1 mm2 swarf then what we are left with?

I'm no way expert in judging what size of work is apropriate for this size of lathe, but for me it is: If the tool tip is towards the centre from the bed way, then it should be fine.

It may be considered a bit picky just to focus on those couple of sentences, but having a 6-7" piece of Ali spinning on a such a light-weight lathe is, quite frankly, a terrifying prospect. Even well bolted down, it still could not be considered wise, there just isnt the needed mass to keep it all stable.

Leave the stability aside, working with some material of that size, the risk of the workpiece breaking loose is also increased, and having a 6-7" diameter workpiece chasing you round the workshop is not my idea of fun


Your illustration of the pneumatic drill is a good one, and it would be a good thing for manufacturers to put a recommended max workpiece diameter list in the manual, but, at least on my mini-lathe, they didnt. That's what I meant when I posted about pushing the machine beyond it's capabilities, because I didnt want someone trying to turn a 6" length of 5-6"diameter steel or even Ali in a mini-lathe based on just the fact that such a workpiece can fit on the lathe, and I especially didnt want them to get the idea from a forum I was a mod of.


Please dont think I am getting at you, personally I think that there could've been a better way of addressing this point, I'm sure that I could've put things clearer, but what has been said, has been said, and I'm sorry that you feel that you have been under a "salvo".



Tim

[mike os]

unfortunately most (all?) of these kind of machines are way overspec on what they can actually handle..... I think twice about 7-8dia" on my colchester & that will handle 12"... 13" in reality, mainly because I dont have the experience, but when someone like Bogs advises something I would take it seriously.

[PekkaNF]

Thank you Tim

I'm content and wish to became contributing memeber of this community some time in the future. I really shouldn't jump on a gun, today I see that what felt like a big deal yesterday does not hurt today at all.

Part of touchiness game from the fact that I find this site very easy going, informative and polite environment. And very international too. We come from very different backgrounds and there are going to be many different people with different set of values and standards.

I'm cool and a little dispilinary action seldom goes in vain!

Pekka

[spuddevans]

I'm content and wish to became contributing memeber of this community some time in the future.

I think that you already are a contributing member of the forum, and I for one appreciate your contributions to the various threads and please keep on posting.



We want all the members here to feel free to post up comments and questions.

Tim

[raynerd]

Chill out and don`t worry about it. I`ve been in your shoes and it just isn`t worth fretting about - I`m too hot headed and would have been much more irrational than your posting of these sensible replies - be cool and forget about it and just keep learning as well all are....

Chris

[Stilldrillin]

Pekka.
We all feel on the wrong side, occasionally.   

I usually sulk for a day or two....... Then I feel better! 

David D

[jim]

Pekka.
We all feel on the wrong side, occasionally.   

I usually sulk for a day or two....... Then I feel better! 

David D

me too!

at the end of the day, its just a forum, not life and death!!

[PekkaNF]

Thanks guys,

You have no idea how pissed I got over the fact that I got pissed!

I was so mad I could not machine anything yesterday. So instead of driking myself silly and go to village center to loud mouth all the tatoed village troublemakers - I took my anger on particulary dirty myford copy that I have used only to turn parts out of wood/corck/such for flyrods. Man it was dirty! I had forgot what piece of klunker it was, removed the chuck and measured the spindle taper. Frigging 0.04 mm of TIR at nose but judging from the shake it's spindle is bent. Bad. I hate the hamfisted klots who bent it, but hey - I got is free. Adjusted the gibs and found out that bed was not overly worn out. This might be good canditate to go "boldly go where no-one's been before", but I'm not that worked yet.

I have one bought QCTP simmering on low heat. Little more cooking, head scratching, staring out with an empty expression and I might come up with an useful way of using same toolblocks (with dedicated tools on some) on two different size lathes without needing to reset height adjustment when taking a block from one lathe to another..good I have weird ideas. I never had a QCTP before, but it's only mere mortals that design and make them. Can't be that difficult.

Cheers,
Pekka