Lofrans Royal windlass - helicoil?

[Gordonmc]

The bolt on the top of the Lofrans Royal windlass is a retainer for a horizontal crown wheel. There is similar under the windlass casing for the opposite crown wheel.
The bolt (stainless) has a habit of chewing the thread on the casing (aluminium).
Has anyone out there had experience of repairing the thread using a helicoil?
If so, tips would be appreciated. Was it possible to use the original bolt which is threaded only for about a third of its length, the rest being machined down to locate in a bush in the crown wheel.

 

[Zorro]

Wurth have a kit out now which is far better than helicoil, I have used them many times on aluminium motorcycle parts with great success, the kit is quite expensive but I am sure that many motorcycle shops and garages now use them and would probabally repair for you quite cheaply.

 

[Skylark]

I'm sure that Mr Google or his sibling Mr YouTube will point you in the right direction, here's one of many examples:-


http://www.nwlink.com/~kbaker/Automotive/Helicoil_12_04/helicoil_12_04.html


Fitting a helicoil into aluminium is common and accepted practice to improve joint integrity of aluminium components.

If the base metal is sound you should have no problems. In the marine environment, dissimilar metals don't get along too well and aluminium often comes off worse. I have a stainless steel guide plate held by a ss bolt into an alloy casing on my windlass and the thread has turned to dust. This is a more difficult problem to solve.

 

[Poignard]

I bought my Lofrans Royale for £20. It was seized up and the previous owner had removed the stub axle for the top bevel pinion thinking, as many mistakenly do, that it was an oil filler cap. He put it back cross-threaded but fortunately, he didn't screw it home fully so the thread was not too badly chewed.

When I overhauled it I simply ran a tap down the thread, making sure it was kept vertical, and that solved the problem. It has been fine for 10 years. Of course it depends how badly the thread on yours is damaged whether this will work.

 

[samwise]

I bought my Lofrans Royale for £20. It was seized up and the previous owner had removed the stub axle for the top bevel pinion thinking, as many mistakenly do, that it was an oil filler cap.

Did the same thing myself, years ago, not realising that these things are supposed to be lubed for life. That bolt can be tricky refit, but fortunately I got it on straight without crossing the thread.

 

[VO5]

The real pain with a Lofrans is removing the screws from the cover plate on the chainwheel side. The nasty little bolts are stainless allens and the body and plate are aluminium, a recipe for disaster. Sod's law at least one will refuse to budge, a real pain. Requests to the manufacturers to treat the threads with copper slip on assembly falls on deaf ears. Awful.

 

[Poignard]

You're right there, VO5. I had to drill them all out of my £20 Lofrans. When I re-assembled it I anointed all the screws with Duralac zinc chromate paste to save myself future grief.

If I ever buy a new Lofrans, the first job I do before before installing it will be to dismantle it and apply Duralac.

 

[VO5]

You're right there, VO5. I had to drill them all out of my £20 Lofrans. When I re-assembled it I anointed all the screws with Duralac zinc chromate paste to save myself future grief.

If I ever buy a new Lofrans, the first job I do before before installing it will be to dismantle it and apply Duralac.

I had two of these blighters freeze on me. I had to remove the plate because the arbor was fractured and needed replacement.

Just imagine the job in the blazing sun in sweltering heat with humidity at 80 %

All this with the windlass still in place on the foredeck.

If the Trocadero Bar ( ) still existed I would have drunk all the beer they could supply

I tried heating and cooling, tapping, WD40, anything you can think of, to no avail.

Finally I drilled them out and put in two helicoils, not forgetting to clean all the threads of the others and dipping into copper lube before replacing and tightening. Phew !

 

[Poignard]

If the Trocadero Bar ( ) still existed I would have drunk all the beer they could supply

Sad that the Troc has gone. What next? the apes?

 

[Gordonmc]

The real pain with a Lofrans is removing the screws from the cover plate on the chainwheel side. The nasty little bolts are stainless allens and the body and plate are aluminium, a recipe for disaster. Sod's law at least one will refuse to budge, a real pain. Requests to the manufacturers to treat the threads with copper slip on assembly falls on deaf ears. Awful.

I have the T-shirt. Two of the six Allens are solid in the plate. Fingers crossed an easy-out and some heat will free them.
Thanks to Zorro for the Wurth tip... the thread replacements are marketted as Time Sert and look like an improvement on helicoils as they secure themselves in situ.

 

[VO5]

Sad that the Troc has gone. What next? the apes?

Come over here and we can go on an expedition.

 

[VO5]

I have the T-shirt. Two of the six Allens are solid in the plate. Fingers crossed an easy-out and some heat will free them.
Thanks to Zorro for the Wurth tip... the thread replacements are marketted as Time Sert and look like an improvement on helicoils as they secure themselves in situ.

Squirting round the heads of the allens with lubricant.
Heating and tapping using a finely pointed punch.
Followed by drilling with a very fine drill.
Followed by application of easy out.
If easy out fails then drill a larger hole and the thread of the bolt is likely to come out in a fractured spiral.
Then drill a clean hole to take a helicoil.
When replacing allens (the six are available as a kit) make sure you lube them first just in case you ever have to extract them again.
Good luck.

 

[Poignard]

When replacing allens (the six are available as a kit)

I bought mine over the counter at an engineers' merchants shop in Croydon. I can't remember what they cost but it was a fraction of the price from the Lofrans agent.