Metalwork advice

[flykeith]

After being quoted £18 per SS bolt 6mm by 220mm, I decided to by the rod and make them myself. Threading them is not a problem but what is the knack in working the other end into a nice 'countersunk mushroom'?
Here is a picture of old and new, the latter having had about half hour hitting with ball hammer.

 

[boatbuilder]

Heat and lots of it, you need to get the metal to a plastic state before it will easily deform.
Have you got a forge locally , that would help.

 

[alexrunic]

originally they would of been formed on a press with the correctly sized and shaped tool / die. I'm sure with a hammer and if you find a large heavy piece of steel to use an anvil that should work. You will need to clean up the end with a angle grinder. failing that you could heat the ends up until cherry red then do the hammering. might want to be careful with both ideas it case of and cracking or work hardening but should be ok if not a major structural fixing.

 

[seanfoster]

Don't plunge it into water or you would harden it and make it brittle.

 

[Poignard]

A blacksmith would do it by "upsetting" , i.e. heating the end red hot [or almost white hot] and letting it drop vertically onto an anvil.

 

[exfinnsailor]

Stainless Welding .. Have a word with your local fabricator .. Be a lot quicker and less stressfull .. Finish on a grinder or with a file ..

 

[pyrojames]

How about threading both ends, making up an inch long piece of 3/8 or 1/2 bar threaded right through internally as a joiner, and then using a conventional short CS machine screw to bolt down the track? You can then remove the track at anytime without having to pull out the whole 220mm and trying to get at the impossible places below deck.

 

[flykeith]

Thanks for the ideas.

These are for the stanchion posts (I'm screwing the track) and as they go through the stringer I need the length. I have heated to cherry red, but was worried about the effect of heat on there properties, maybe MrStainless will sort me out.

Hoping for first sail this weekend /forums/images/graemlins/smile.gif

 

[dan9487]

Dont know if this is any help but A2A4.com do a stainless M6 x 220mm cap head screw, they dont state a price but their M6 x 160mm cap heads are only £1.27 each so you might be able to save yourself some trouble and money!

 

[Niander]

i would of used threaded bar...
and if you dont want a nut showing on top screw on a nut but not all the way and stainless weld the top then grind flat...easy..long as you want.

 

[Cliveshep]

Put a 6mm nut onto a piece of 6mm set screw, i.e. where there is only a short thread, cut off bolt end, put in chuck of drill, clamp drill into vice or workmate, spin up and bevel with a mini grinder. and also round off. Remove from drill, unscrew bevelled nut, put onto new rod threaded say 6mm down, weld down on top, grind smooth, polish with sander, belt or disc, using fine grit - thread the other end - bingo - a c/sunk bolt any length you like! Assumes you have a welder or access to one, plus you will need monel metal rods if you don't want it to rust.

 

[fishermantwo]

I do this regularly by drilling out the thread on a SS nut to suit. Slide it on the end so that there is a small hollow and weld in place with ss rod and arc welder.