| Gallery, Projects and General > Project Logs |
| Making a milling vice |
| << < (13/16) > >> |
| Beone:
It's worth a try to stress relieve an al casting to be machined by baking it for 5 to 8 hours at 450-500 degrees Dave |
| NormanV:
I've cast it again and this time had a bit of an 'event'. As the header and riser filled to near the top the mould opened and metal started leaking out of the side. I rapidly put my foot on top and pressed down, that stopped the leak. I poured in the rest of the metal from the crucible and waited for the metal to have a chance to solidify before I removed my foot. To my surprise I still got a good casting, there is quite a lot of contraction at the riser end but there is enough metal there to do the job. I think that I might take Beone's advice and stress relieve the castings in the oven. Beone it might have been a good idea to specify the units when quoting a temperature. When I made my first furnace Dave Gingery suggested curing it at 400 degrees in the oven, I did not give it a thought and set the school workshop oven at 400 degrees and nearly burnt the school down 400 degrees Celsius is very hot! |
| Beone:
Oh! Yeah! That's Fahrenheit if I set my wife's oven for 500 Celsius I would burn the house down! Dave |
| NormanV:
I've stress relieved both castings in my domestic oven. I had planned to leave them in for 5 hours but fell asleep so they were in the oven for nine hours. I was a bit concerned about the cost of electricity but was pleased to find that it only used £3 worth. I'll start machining the new one tomorrow. |
| NormanV:
I've now got the second casting almost to the same stage as the first one but even this warped slightly. When I took it off the mill after milling the base yesterday it sat absolutely flat on a surface plate. By this morning it had developed a slight rock, it is not a major problem as it straightens out when I clamp it down. You may notice from this photo that I have added mounting lugs to fit the tee slots on the milling table to enable me to mount it in either direction on the mill. Tomorrow I will start working on the lead screw that Philf kindly sent me. |
| Navigation |
| Message Index |
| Next page |
| Previous page |