Keenserts

[sako243]

The casting is so large you'll never get the heat into it to TIG braze.

Thats the mixer there.

Would a couple of reamed holes for locating dowels in between the mounting bolts to take some of the shear loading / vibrating off the bolts. Although I guess it'll still have the same effect unless it was substantially bigger.

 

[George A2Y]

The casting is so large you'll never get the heat into it to TIG braze.

Thats the mixer there.

Would the material / layout allow the drilling and tapping of a couple of extra fixings between what is there?

 

[Keithmac]

I'm a fan of Wurth Timeserts, with a dab of permanent lockthread occasionally job dependant.

 

[Brad93]

I'm a fan of Wurth Timeserts, with a dab of permanent lockthread occasionally job dependant.

Horrendously expensive. I've bought 4 sets of these for less than one set of timesert from
wurth

 

[Keithmac]

You get what you pay for, high quality thread repair system.

 

[500e]

And machine not replaceable. So cost is immaterial if the do the job

 

[Seadog]

You get what you pay for, high quality thread repair system.

You never watched the recent youTube video, then?

 

[smashweld]

Thats 3yrs... Which is enough for a new expensive car - let alone a few repair bolts in a "dough mixer"

What about filling the holes up with TIG braze and drilling and tapping them. All least if it all fails in another 3yrs - you can rework it...!

for curiosity...how old was the mixer when you did the first repair Brad?

 

[Keithmac]

You never watched the recent youTube video, then?

Never had an issue with a Timesert personally, into aluminium or steel.

 

[Seadog]

There was another thread on here where a comparison of the most common repair systems was carried out. The Wurth and Keenserts didn't perform spectacularly better than cheap Helicoils, if my memory hasn't failed.

 

[hotponyshoes]

Timeserts are good if you don't have much space around the damaged thread or you just want to put a hard thread into a soft material.
It's very hard to get any sort of locking on them if you are installing them by hand so you might want a locking compound (which in the case of the op would presumably need to be food safe?)

Keenserts are good if you have the space around the damaged thread.
The thin wall ones are a bit bigger than a timesert. The heavy duty ones are a lot bigger. On a soft material (like his cast iron) that gives a much larger surface area to distribute the stress and vibration.
Hand installing is easy and the locking is permanent. You don't use compound so there is nothing to fail due to heat or age and nothing that will break down under vibration.

 

[hotponyshoes]

There was another thread on here where a comparison of the most common repair systems was carried out. The Wurth and Keenserts didn't perform spectacularly better than cheap Helicoils, if my memory hasn't failed.

If you took a block of metal, fitted one of each type of insert, fitted an eye bolt and tugged at it until it pulled out I wouldn't expect a massive difference between any of them.
Or, an original thread in steel either for that matter.

The thing is, when you need to use one it's because the original thread has failed for some reason.

If you know what the reason for the failure is then there is normally a 'best choice' insert to use.
You may have to compromise from there depending on the accessibility, budget and so on..

I expect if you repeat the test for all the inserts under the conditions of failure the 'best choice' insert would be better!

 

[smashweld]

do the mating parts need to be disassembled for cleaning/servicing??

 

[Dozzer]

Reading through @Brad93 description and pics, the one thing i might look for is small cracks in the casting, just in case they are allowing the bolts to come lose. quick die pen tests would show.
The fact that its lasted this long is a testament to the last repair.

 

[Brad93]

Belzona in the three bad holes to enable more accurate drilling as per @hotponyshoes recommendation above.

 

[Brad93]

Job done.

Drilling wasn't without its problems but we got there in the end. The belzona while it did help probably needed a few days to fully cure. I reckon the drill still would have wanted to grab due to the oval hole.

If it breaks again in 3 years time I'll take the mixer to one of my customers and do the holes with the horizontal borer and an end mill.

These are the Lightweight keenserts. KNM10x1.5

12.7mm drill as recommended by Luke. A good call as 12.8 would have been sloppy I reckon.