You would need to buy wheel hubs that have electric brakes and fit your axle and mounting holes. Replace your existing wheel hubs with the hubs that have brakes. I do not see how you need any welding etc, it should be straightforward if your trailer uses standard axles that have provision for brake hubs (square plates with predrilled holes to hold the brake hub).
If not, you can always buy a new axle with brakes etc installed. It is not that expensive.
You'd also need a brake controller (~$100) and the associated wiring installed on the tow vehicle. Surge brakes are really great on boat trailers because they are non-electric. Electric brakes on boat trailers are often submerged when loading and unloading the boat. It's only a matter of time b/4 this causes electrical problems. I've had both systems and prefer electric on all my trailers, EXCEPT boat trailers. I don't know of any trailer manufacturers that use electric brakes on boat trailers, perhaps for that reason. They all seem to use surge brakes. Just my $0.02, your mileage may vary. Paul
I've bought a lot of stuff from Northern Tools over the years. I never had one problem.
They have a lot of oddball items that are hard to find locally in many cases. Their stuff is all made pretty good.
I like looking through their catalogs for items that I didn't even know they made for a particular use. For those times when you have a yen to buy some tools, but can't find anything you don't already have at least one of.
Like a bung wrench. I never knew they made such a thing, and now don't know how I lived without one for this long.
They are local to me. Back in the 70's (??) a couple guys were trying to build a log splitter couldn't find suitable parts and especially the 2 speed pumps. One they found the items, they decided to do some mail order out of their garage. And on from there.
They used to have nifty "tent sales" for all their catalog returns. I'm really proud of my 2hp TEFC motor for $.50 (half a buck).
Ok, Paul. Iggy backed me up to re-read your message. I think I got it this time.
But there is still a fly in my pudding.
This boat is NOT a centerboard type. She's a proper (though tiny!) yacht with a ballasted fin keel. (there is a picture of her on the trailer on my web page)
The trailer has an extendable tongue (6 feet stock plus I've made an extra 12 foot one to deal with the low water levels in the lakes around here. It has worked well, and I've welded hangers on the trailer to haul it along with me.
With electrics I could unplug the brake cable when extending (or swapping) the tongue(s).
What I recall of the surge system on Lew's trailer, that would be sorta a problem?
So I'm back to fantasizing about a hybrid system with an electric controller but hydraulic brakes.
Waybe weld them to the drop stubs (about 6 to 8" long) to avoid distorting the bearing mounts?
There is a Northern Tool over in Garland. Guess I'll go over there and get some measurements.
As a note, while at the hard stand today I checked out a bunch of other trailers for brakes. Almost all had surge brakes (like Paul said!) BUT... NONE of the extended tongue trailers had brakes of any kind.
Your welding for the weld on plates would have to be very accurate for hubs to fit with the brakes etc (the stationary part to fit the rotating part so that brakes works and are very well aligned). Not very easy.
When I built the brakes for my last airplane the back plate had a center hole that just fit the axle tube. Self centering! I just had to line it up longitudinally and vertically. Went together real nice.
Dunno about this one tho, as the axle tube is way too big for my drill :( (no machine shop next door now)
See if you can work backwards, attach a plate to the outer hub, put everything together, see where the plate ends up, and then you need to weld it on to avoid substantial distortion... Not very easy to say the least...