# Thread: 1045 precision ground shaft deflection

1. ## 1045 precision ground shaft deflection

I'm trying to find te deflection of 1045 ground shaft 1" in length of 5' down any ideas?

2. Way too high. :-) Get yourself a copy of Beamboy and let it do the analysis for you. (Google Beamboy)

3. Cool little prog, any ideas where i can find 1045 round bar properties?

4. Deflection will be EXTREMELY close to the same as 1040, 1020 or 1010

5. There was a BIG arguement on this subject on another board, but what I learned from it is that the deflection is related to the modulous of elasticity of the material, so all kinds of steel in any heat treat condition will all have roughly the same deflection :-).

makes sense if you think about it..

Yes the ultimate tensile and yield strengths will vary greatly in differant alloys and heat treat conditions, but not the deflection....it all changes when the deflection force exceeds the yield strength of the steel, but until that point all steel will act very similar.

Bill

6. 1" over 5' = nightmare.

Modulus of elasticity of steel = 30,000 ksi

Area moment of inertia of a 1" bar = pi(0.5)^4 / 4 = 0.049

Beam deflection with rigidly supported ends, let's say 50 lbs force:
= Wl^3 / 192EI
= ( 50lbs * 50"^3 ) / (192 * 30,000,000 * 0.049)
= .022"