11-10-2016, 02:20 AM
I tried something this afternoon that I have not done for about 25 years, using the oxyacetylene torch to straighten a shaft. The results were very confusing and I'd be interested in opinions as to why.
I set my mill up with the horizontal arbor for the first time yesterday and discovered that the arbor is bent- it's a 1" shaft about 20" long with a NT50 drive end. After discovering the shaft was bent, I put it between centres in the lathe and measured the bend with an indicator- the bend was right in the middle and there was about .037" bend, i.e. the indicator read .037" difference between two points 180 degrees apart around the centre of the shaft.
I put the shaft on some blocks, applied heat to the apex of the bend (i.e. the high spot) and then quenched it with water. Put it back in the lathe and the bend was now .010" less. Repeated the procedure and this time the bend was worse than when I started, had about .045" bend at the same point. Repeated the procedure, heating the high spot and quenching with water from a jug. this time the bend was .052".
Thought I might be doing it wrong after all these years, so I heated and quenched the inside of the bend. A slight improvement, back to about .040". Tried the same again, and was back to .050". I have now tried more heat, less heat, heat the inside of the bend, heat the outside, and the results have been random- no pattern to what seems to pull the bend in the direction that I want to. I'm now back to the starting point of about .035" bend in the same place as where it was originally. I think I'll be up for a new arbor but I'm puzzled as to why this procedure has produced such random effects.
I set my mill up with the horizontal arbor for the first time yesterday and discovered that the arbor is bent- it's a 1" shaft about 20" long with a NT50 drive end. After discovering the shaft was bent, I put it between centres in the lathe and measured the bend with an indicator- the bend was right in the middle and there was about .037" bend, i.e. the indicator read .037" difference between two points 180 degrees apart around the centre of the shaft.
I put the shaft on some blocks, applied heat to the apex of the bend (i.e. the high spot) and then quenched it with water. Put it back in the lathe and the bend was now .010" less. Repeated the procedure and this time the bend was worse than when I started, had about .045" bend at the same point. Repeated the procedure, heating the high spot and quenching with water from a jug. this time the bend was .052".
Thought I might be doing it wrong after all these years, so I heated and quenched the inside of the bend. A slight improvement, back to about .040". Tried the same again, and was back to .050". I have now tried more heat, less heat, heat the inside of the bend, heat the outside, and the results have been random- no pattern to what seems to pull the bend in the direction that I want to. I'm now back to the starting point of about .035" bend in the same place as where it was originally. I think I'll be up for a new arbor but I'm puzzled as to why this procedure has produced such random effects.
Lathe (n); a machine tool used in the production of milling machine components.
Milling Machine (n); a machine tool used in the production of lathe components.
Milling Machine (n); a machine tool used in the production of lathe components.