Thread: He's added a fourth axis
Sometimes cheaper is illusionary.......
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.
Why do you ask so many questions when it appears you know all the answers ?
.John S -
29-07-2010 #15Why do you ask so many questions when it appears you know 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.
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....
29-07-2010 #17I 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....
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:
30-07-2010 #19That wasn't what I was refering to.... there's more than one tolerance spec on a bearing
30-07-2010 #20That wasn't what I was refering to.... there's more than one tolerance spec on a bearing
I'm just looking at the z axis and spindle design for mine and the design of spindles is very complex, It seems to boil down to tapered bearings for high load, low speed (10000rpm or less) and angular contact for every thing above.
There is the option of using deep groove bearings as they are capable of the highest speeds and stacking them in 4 or 5 deep to regain the load and ridigity, but the precision might not be there.
But I guess you knew that
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