Bending Trailer

[Pete7]

Originally Posted by Limey Linda

Temp. of process is 460 C. maybe enough to case harden. It is only a guess as I could not think of another reason, unless the steel was hardened in the first place. It is HARD.

Its been a while but I thought case hardening normally involved adding extra carbon to the surface whilst hot, then quickly cooling it? Could the surface work hardened as you were drilling it.? Surely the galv process of heating and cooling it would result in annealing.

This doesn't help Hightower though. Andy suggest you bring the draw bar along to the next church as well as the prop

You could try ditching the draw bar and replace it with a straight piece. Then double it with another on top which the frame bolts to with JWs idea of angle iron, so you end up with an over/under like a shotgun.

Pete

[Hightower]

Originally Posted by Pete7

Its been a while but I thought case hardening normally involved adding extra carbon to the surface whilst hot, then quickly cooling it? Could the surface work hardened as you were drilling it.? Surely the galv process of heating and cooling it would result in annealing.

This doesn't help Hightower though. Andy suggest you bring the draw bar along to the next church as well as the prop

You could try ditching the draw bar and replace it with a straight piece. Then double it with another on top which the frame bolts to with JWs idea of angle iron, so you end up with an over/under like a shotgun.

Pete

I was trying to keep it DIY and keep the costs and hassel down a bit. doing it JW's way I'd have to weld plates on the ends of the side pieces so that it would become a stable platform for the angle iron bits, afterwards the two side of the frame would need dipping.

What I was thinking of was a new upgraded draw bar, but instead of a bend two pieces of box welded together to get the height right for the cross member.

Then I was going the have two plates made up that would go down the side of the side frames, angled at the joint area and up the draw bar, each plate would have angle iron welded to the back to locate the frames and U bolts atc to hold it all in place.

What you think?

[jwalker]

Andy, what section is the drawbar and what is it's thickness?

[Hightower]

Originally Posted by jwalker

Andy, what section is the drawbar and what is it's thickness?

I haven't a clue, was planning to take a look, untill the front offside brake caliper on my Rover decided to seize up yesterday, rendering it U/S. I've had to replace the caliper, discs and pads today, lucky the bearings seem OK

I've a job interveiw tomorrow, taking my boat to get measured up for it's new screen rail, paying my car tax for another year and going to work....I'll try to fit it in

[jwalker]

OK. When we know the sizes, it'll be easier to move forward.

[Top banana]

Andy. If that was my trailer, id list it in the bits for sale section,on this forum no one will ever know. and get my self a beefier trailer.

Ps. maybe just leave it a couple of months first.

It must be a week for trailer problems. Id picked mine up from upholsterers on friday, for got to take the hand break off. and 5 miles down motorway got stopped with flames coming from both wheels.luckilly there was a canal running along side. so off went my mate for several buckets of water.
spent yesterday collecting and fitting new complete axle.Oh for the joys of boating.

[Limey Linda]

Originally Posted by Hightower

I've had to replace the caliper, discs and pads today, lucky the bearings seem OK

Ouch, I bet that was pricey. You sound like a very busy man. Regarding the trailer. Have studied the pics; it is very light weight construction. I would cut out the tow bar and fit a new one as previously suggested. I would also pay attention to the mounting of the winch post while you are at it as it appears a little flimsy.

[Limey Linda]

Originally Posted by Pete7

Its been a while but I thought case hardening normally involved adding extra carbon to the surface whilst hot, then quickly cooling it? Could the surface work hardened as you were drilling it.? Surely the galv process of heating and cooling it would result in annealing.

Pete

The case hardening process you are thinking about is used for steel with no carbon. If the steel already has carbon in it it will harden unless the temp. is lowered slowly, which is annealing. If they took it out of the zinc bath and sprayed it with water it will harden. No, it did not work harden as you would get with a skidding drill bit.

[bedajim]

Hi

Can you not place a box section from the back of the blue label each side to near to the front handles on the draw bar (like a second A frame) and either make up a plate and bolt through or u bolt them in place and then have a couple of cross sections to sandwich the existing bars one behind the existing A frame joint and a couple in front to add support, spread the load

Or make up a new draw bar like a ladder on its side with a second box spaced under the first to give more support

[Hightower]

This is what I had in mind.

Excuse the wonky look of my rough sketch, it is late

Original on left modded one on right.

The reason I have designed it like this is that I can have it made seperate and fit it in an hour.

[bedajim]

Originally Posted by Hightower

This is what I had in mind.

Excuse the wonky look of my rough sketch, it is late

Original on left modded one on right.

The reason I have designed it like this is that I can have it made seperate and fit it in an hour.

But if you don't bring the bracing forward it will still be weak where it finishes

[jwalker]

Originally Posted by Limey Linda

The case hardening process you are thinking about is used for steel with no carbon. If the steel already has carbon in it it will harden unless the temp. is lowered slowly, which is annealing. If they took it out of the zinc bath and sprayed it with water it will harden. No, it did not work harden as you would get with a skidding drill bit.

There is no such thing as steel with no carbon. Steel is a alloy of iron and carbon. Low carbon steels will not harden and case hardening is the process of adding carbon to the surface of the steel so that it contains enough carbon for the surface to be hardened. There is a general modification to this terminlogy and case hardening also appears to be used to describe surface hardening of carbon steels. For the steel to harden, it needs to be raised above its upper critical point. This varies for different steels but is generally above 700°c.

Raising the temperature to just above the melting point for zinc would succeed in fully tempering a hardened steel and so reduce its hardness.

The maximum tempering heat is about 700°F so maybe that is a confusion.

However, there are various ways in which a steel can become hard and one of them is work hardening. A cold rolled steel can become very resistant to drilling, especially drilling at high speed.

The other way your trailer could be a hard steel is it's made from bed irons. Those bu**ers can be really tough.

[jwalker]

Originally Posted by Hightower

This is what I had in mind.

Original on left modded one on right.

The reason I have designed it like this is that I can have it made seperate and fit it in an hour.

I don't think you need the shorter cross bar. Your design will be much better than original because of the longer lever to the attachment point but you are still concentrating the load at those cross bolts so that is the area you need to strengthen. I see your angle but you need to take it forward a distance to stiffen up that section of the draw bar and distribute the load. It will also be better being clamped at the ends.

Your draw bar looks to me to be too flexible for that application because of its length and section and I'd bet it was a tad springy at the front until you pulled the boat down onto the snubber. My preference would be to use a section, say 120 x 60, keeping the top of it at the same level as your drawing and cut a corner out of it where it overlaps your cross member to keep the alignment level. Weld up that end to prevent crushing. This would allow the lower bolt at the front to pass through the tube. It wouldn't be the ideal dead centre but it would be sufficiently close. Any other stiffening you added there would be an advantage.

[Nos4r2]

I agree with everything Jono's said about welding it

What I'd do is a bit more radical-that drawbar looks like a Friday Aftenoon Special.

I'd do it this way:-
Remove your FUBAR drawbar and the T piece.
Cut the flat plates that clamp round the drawbar off the main chassis rails.
Buy a nice big chunk of galvanised box section that's a bigger section and with more wall thickness to use as a new drawbar.
Trim the chassis rails back a bit to suit the bigger drawbar and longer thicker clamp plates-use 4 bolts instead of two in the new clamp plates.
If possible,bolt the drawbar rather than weld it to a nice shiny new T-piece.
Use a different method of U-bolting the T-piece to the main rails-those plates on one edge look like they'd support some cheese but not much more.

Obviously there'll be a bit of 'making it fit' in there-but that 2 bolt clamp,U-bolted T-piece plate and welded T-piece that Admiral made it with are (scuse the language) worthy of CAN.

The results should be a bit like the pic below.

[mike-stgt]

I would take some tubes 60x40mm and 2 plates 100 x250mm and weld it as shon in the drawing . This should be fixed over the crossboow section with 4
u-bolts like a bridge to take the tension away from this single point.
Mike

[Jono]

Originally Posted by jwalker

Those bu**ers can be really "Grumpy Stuff ™"

.....™ JW

[Kernow Buoy]

Andy,
These people suggesting you modify your trailer are not your friends
There is a much simpler solution, your trailer looks ideal for a smaller Rib, perhaps a 5.35 with a 90 hp, my trailer however is a little large for my Rib, as unlikely as it seems I would be willing to swop boats (for free )
your friend
Kernow

[Mollers]

Originally Posted by Kernow

Andy,
These people suggesting you modify your trailer are not your friends
There is a much simpler solution, your trailer looks ideal for a smaller Rib, perhaps a 5.35 with a 90 hp, my trailer however is a little large for my Rib, as unlikely as it seems I would be willing to swop boats (for free )
your friend
Kernow

Taking into account that Kernow's trailer has been converted form horse drawn.

[Hightower]

Are there any trailer manufacturers in Hampshire that could manufacture a new custom draw bar?

Andy

[bedajim]

Originally Posted by Hightower

Are there any trailer manufacturers in Hampshire that could manufacture a new custom draw bar?

Andy

You just need a firm of metal bashers and a sketch, far cheaper too