He's added a fourth axis

[ecat]

The other thing to bear in mind is ... making parts yourself does not always work out cheaper ... and here speaks the voice of experience

... and then you figure in not only the build time but also the time spent learning how to build the device, how to spec the parts etc..

[irving2008]

Yeah,but you're using an off the shelf poduct here which is adapted to suit the needs,Irving...I'm talking about making and constucting the parts ourselves to reduce overall cost which has been shown in the two previous vids I posted..

Ignoring the cost of the stepper/control/chuck which are roughly common, the aluminium to construct that axis would be about £30, the steel spindle about another £15, the bearings about £15 and the pulleys/belt about £18 and machine screws etc about £10... you might do marginally better, but by my calculations the parts alone are £88, my rotary table was £40, the conversion parts about £10; it took me a lot less time to convert and only needed the lathe, no CNC milling machine....

Sometimes cheaper is illusionary.......

[GeorgeD]

You shop dear there,Irving

You have only to enter a scrap metal yard and you will pick up a couple of bars of metal for a fiver,Aluminium well its debatable whether this is an expensive matrial considering it can be gained for nothing in terms of collecting it in bits here bits there and then casting it.

Any aluminium fabication/machine shop will let you have unusable(off cuts)for a few quid,enough to melt down for a component.

Bearings,well yeah it pays to aquire new...just sent off on ebay for 2x 67x30x17mm roller bearings at £8 inc P&P

Its just me,I like to construct more than buy stock items as I get more pleasure out of it.

It is true that its sometimes cheaper to buy already built and assembled products but if we do the pricing up of components and put alongside the shop bought component then that is the decider before shelling out.

[irving2008]

You shop dear there,Irving

You have only to enter a scrap metal yard and you will pick up a couple of bars of metal for a fiver,Aluminium well its debatable whether this is an expensive matrial considering it can be gained for nothing in terms of collecting it in bits here bits there and then casting it.

Any aluminium fabication/machine shop will let you have unusable(off cuts)for a few quid,enough to melt down for a component.

Bearings,well yeah it pays to aquire new...just sent off on ebay for 2x 67x30x17mm roller bearings at £8 inc P&P

Its just me,I like to construct more than buy stock items as I get more pleasure out of it.

It is true that its sometimes cheaper to buy already built and assembled products but if we do the pricing up of components and put alongside the shop bought component then that is the decider before shelling out.

You must be very lucky then George...

Well all the scrap dealers around here and fabrication shops seem to know the value of their scrap... 'cos they wont give it away and they charge about the same as eBay sellers.. about £5-£7/kilo. To make that you arent looking at scrap but some quality tooling plate I doubt you'd easily find that in a scrap yard. And do you know what form of aluminium you are getting from a scrap yard, will it be machinable?

I hope the bearings you bought arent those advertised as 'transmission' or 'wheel' bearings... their tolerances aren't anywhere good enough... then again with only a ruler and no DTI you'd never know how bad they really are....

[John S]

George,
Why do you ask so many questions when it appears you know all the answers ?

.

[GeorgeD]

Why do you ask so many questions when it appears you know all the answers ?

Gotta keep the foums alive somehow,and I don't have all the answers.

A visit to a scrapyard can reap benefits particulary if its one that deals in industrial maching scrap and there's plenty of those down south,not many in this neck of the woods.

[GeorgeD]

I hope the bearings you bought arent those advertised as 'transmission' or 'wheel' bearings... their tolerances aren't anywhere good enough... then again with only a ruler and no DTI you'd never know how bad they really are....

Now,now Irving just because you lot can't sort the £24 power supply out,no need to take it out on us gentle folk.

I've had bearings off this blokey before and the tolerence was within their bore diameter ie they were a tight fit and had to be pressed on with tube and rubber mallet

Its a well known fact that the further south you go the higher the prices get.

ps I do have a Micrometer and I know how to use it.:whistling:

[irving2008]

....the tolerence was within their bore diameter ie they were a tight fit and had to be pressed on with tube and rubber mallet...

That wasn't what I was refering to.... there's more than one tolerance spec on a bearing and the one one the central bore diameter is one of the least important...

[GeorgeD]

That wasn't what I was refering to.... there's more than one tolerance spec on a bearing

Axial forces or Friction?

[Tom]

Axial forces or Friction?

I fancy a "Friday night pub quiz"....

George, the question is in two parts:

1) What is the difference between these two identically sized bearings? The answer I'm looking for is not £12.03
http://simplybearings.co.uk/shop/p17...duct_info.html
http://simplybearings.co.uk/shop/p51...duct_info.html

2) Assuming it was suitable for the task, which one would you install into your (hypothetical):
a) Moon lander
b) Nuclear submarine
c) Power station
d) Gantry crane
e) Precision 4th axis
f) Miscellaneous 23.5hr/day, production critical machinery
g) Front car hub
h) Rear car hub
i) Shonky 4th axis built as a learning exercise

Winner gets a pint. *In true pub quiz style, I reserve the right to fall asleep before the end of the discussion and not notice it's all finished until I see that all but one table is looking depressed.

By the way, it's not a loaded question. I haven't built my first shonky 4th axis yet, but when I do, it WILL be shonky.