Re: small mill for machining steel. Max spend £500 including computer
Re: small mill for machining steel. Max spend £500 including computer
I thought I would post an update on the mill progress. I have been a bit busy fitting a kitchen, drawing tractors for my son and somwhere along the way had time to make anther sprog - due soon!
As you can expect progress has not been great on the mill front, however I have the spindle operating and have made some cuts in delrin then steel . The machine performed ok but I am now making improvements. The next few post will bring you up to latest progress
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Re: small mill for machining steel. Max spend £500 including computer
These shots show the spindle drive pulley arrangement. Tensioning of the high speed belt is achieved by rotating a block in which the counter shaft is mounted (eccentrically). The low speed (v belt) is tensioned by rotating the pulley assembly.
Attachment 3791Attachment 3789
note that no guards have been added yet but are on the list before the mill is complete.
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Re: small mill for machining steel. Max spend £500 including computer
The anti backlsh seemed to work ok but I had an idea how to improve them. I modified the design so that the two nut halves are radially fixed to each other but axially free. this was acheived using 4 off 3mm rods in close fitting holes in both nut halves. The slave nut is threaded with a fine thread and an outer collar threaded on. this is biased with a tprsional spiring to take up any backlash. hopefuly this greasy sketch might help - it was used when I was machining the parts so it is not the clearest:
Attachment 3792
drilling the holes for the rods in the nut halves
Attachment 3793Attachment 3794
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Re: small mill for machining steel. Max spend £500 including computer
machining castelations in the collar
Attachment 3795
some surgery to the bed to fit the larger diameter nuts in - I love machining cast iron!
Attachment 3796
X axis nut in position but biasing spring not fitted over collar (lash up wiring shown!)
http://i1031.photobucket.com/albums/...20mill/132.jpg
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Re: small mill for machining steel. Max spend £500 including computer
one more picture showing x axis nut
Attachment 3797
Re: small mill for machining steel. Max spend £500 including computer
Re: small mill for machining steel. Max spend £500 including computer
thanks for sharing your build keep up the good work.
Re: small mill for machining steel. Max spend £500 including computer
Cheers all
BillTodd I looked up you roller nut for your mill conversion when I was wondering what would be a good low cost ballscrew alternative. Are you still using this and if so how is it going? I would be interested to see how the nut has worn. I decided against it as the chosen solution for a couple of reasons:
mainly space - it is tight enough with the current arrangement and i am not sure that I could have got a roller screw to fit without making it more complecated
Time - it seemed a time consuming (but rewarding) method
but could see the efficiency advantage.
Re: small mill for machining steel. Max spend £500 including computer
Quote:
BillTodd I looked up you roller nut for your mill conversion when I was wondering what would be a good low cost ballscrew alternative. Are you still using this and if so how is it going?
They're working really well, well enough for me to consider replacing the fixed nuts on my Haighton as well.
As you say, the space requirement is the main drawback. I've been eyeing Mike Everman's quad bearing design and wondering if I could use it with some compact bearings instead of my twin roller type.
Bill