Roller Shaft Alternatives

[Luke000]

I am in the process of rebuilding my trailer for my new 1959 Lone Star El Dorado. The trailer is the original one that went with the boat, a Lone Star Road Crown. I am in the assembly process right now and i found out that the old shafts for the 8 rollers got thrown out, so I am in the the market for some new ones. The local trailer store is out of the 19 inch sections that i would normally cut up into the 7-inch sections. The ones on ebay are super expensive (about $18 a pice and i would need 4) and would take a while to get to me. I have a metal yard not too far from my house and they would cut up a section of 5/8 diameter 1018 mild steel in any length I need. All the metal I would need would be less than $10 and I just would get some end caps from my trailer shop. Is there any reason I should not go this route? The boat should weigh less than 1500-1700 pounds when it is water-ready. From what I can tell, the purpose made roller shafts are nothing special metallurgically besides being galvanized.

 

[smokeonthewater]

personally I would want hardened or stainless but the WORST the mild steel will do is bend or rust... It's your call

 

[Luke000]

I just checked with the metal shop and I can get 5/8 round bar in 304 stainless for $5 a foot or the 1018 MS for a little under $2 a foot. I know the stainless has been annealed so I don't know how well it would hold up against the 1018 in terms of possibly bending. It would be FAR better for rust resistance. Is the 304 annealed stainless more or less likely to bend than mild steel in this application?

I have some left over scrap from the roller shaft (purpose made) and it does not appear to be hardened steel and I know it is not stainless.

 

[Luke000]

After doing some quick research I found that 304 stainless seems to be the stainless that the manufactures use for their higher end shafts. 304ss vs 1018ms mechanical properties have the stainless beating out the mild steel in tensile strength and in the charpy impact test. So I think stainless it is for me. If anyone has any other input please chime in

 

[Scott Danforth]

304 does rust, 316 does not , however it doesnt have enough carbon in it so it is really soft. for shafting, we use 17-4PH at work unless it is below the water line. then we use either polished 316 ( in compression only) or aquamet 17

if you plan on using 304, I recommend passivating it unless you can live with it rusting. the passivation process does change the material properties a bit.

how is it loaded? what is the loading on each roller? for a loading of only a few hundred pounds or less, the 304 would be fine, and you may even be able to go to 316 or 316L. if it is heavily loaded, then I recomment 17-4PH-900

 

[Luke000]

304 does rust, 316 does not , however it doesnt have enough carbon in it so it is really soft. for shafting, we use 17-4PH at work unless it is below the water line. then we use either polished 316 ( in compression only) or aquamet 17

if you plan on using 304, I recommend passivating it unless you can live with it rusting. the passivation process does change the material properties a bit.

how is it loaded? what is the loading on each roller? for a loading of only a few hundred pounds or less, the 304 would be fine, and you may even be able to go to 316 or 316L. if it is heavily loaded, then I recomment 17-4PH-900

Well it is amazing what a nights sleep will do- I just realized i was looking at the wrong set of data last night for the 304 . The yield strength is about 25-30,000 PSI where as 1018 steel has a yield strength of about 54,000PSI! So it looks like I am just going to pick up some 1018 for this project.

Scott, I wanted to get some 17-4, but the place i have only has 1/2 inch or 3/4 in that size and I dont have a lathe to turn 8 bars down- plus it would be a lot of extra work. this is going to be a fresh water boat so I am just going to have to deal with some rust, the original ones from 1959 seemed to hold up quite nicely and those were just steel.

 

[Scott Danforth]

1018 will rust and swell, and then your rollers wont turn.

you can send out the CDS to have it galvanized.

Or you can buy 17-4 from mcmaster carr and have delivered to your house http://www.mcmaster.com/#stainless-s...y-rods/=tymlas
or you can also look at 410 stainless. http://www.mcmaster.com/#stainless-s...y-rods/=tyml4q

17-4PH-H1050 is about 100ksi, 410 is 40ksi

your trailer was probably originally made with A36 which is 36-51ksi material