Hi Guys,
Need some help. I have been new Robart 630 structs, which are supposed to be 1/2 inch diameter. I measured them, and they exceed 1/2 inch by 4-5 thousands of an inch. So far so good. I have brand new Sierra Precision replacement trunions. Measured the hole and it's 2-3 thousand of an inch LESS than 1/2 inch diameter. Therefore can't get the struct inside the hole. [:@]

I can try to put some extra muscle into opening the trunion hole with some leverage. No sure how much can I go before damaging the trunion. How much bigger than the struct the hole must be so that I can install it ok?

Last time I had exactly the similar issue with the Robart trunion. Ended up forcing it using a hammer. What I didn't realize its that doing that, I would be unable to get it out in the future . don't want to do the same mistake twice.

I would have though that something like this will not be required if I'm buying the right parts.

Help.

Thanks
Edgar

Sorry, maybe I am missing something here but there is a clamping bolt that tightens the trunion around the strut. Therefore, the strut hole should be of variable diameter, depending on how tight the trunion bolt is. See picture with Sierra version on the right, original Robart on left. I must not be understanding your issue.

Keith.

The diameter of the hole in the trunion is too small, even with the screw taken out completely. I will try to "sand" the strut down to make it fit. If that fail, I will try to enlarge the hole in the trunion.

Regards,

Just take the bolt off the trunion, get yourself a wide flat screwdriver, insert it into the incision on the trunion, and gently tap it with a hammer to widen it.

You do not have to sand the strut.

Try it, it works every time. If you can put it in using above prescribed method, you can also take it off when need using the same methodology. Just make sure you do not over tighten the bolt on the trunion and put indentation or deform the strut.

To make sure you're pickin' up what the Ghost is puttin' down here's a pic.....

Kevin

ghost,

I tried that, but was afraid to damage the trunion... Maybe I should just put some more muscle to it...

I've got three brand new Robart 630 trunions I'll sell for $40 shipped for all three if you want them for spares...I'm going to post them for sale right now in the "Jet Hardware" section....

Kevin

Wanted to post my solution for the record...

Couldn't get the struct hole opened enough with a screwdriver. Ended putting back the bolt in the trunion, screwing it completely. Once 'closed', I used a drill press with a 1/2 inch drilling bit. This resulted in just taking out enough material. After taking out the bolt, I used the screwdriver method and opened the hole, inserted the struct and screw the bolt in. Perfect.
Tried with several structs, all fine.
Thanks for the suggestions.
Regards,
Edgar