Stripped threads on 510 table

[fturner]

Does anyone have any experience with using inserts to fix stripped threads? One of the trunnion mounting holes on the underside of my table is stripped.

[dicksterp]

Does anyone have any experience with using inserts to fix stripped threads? One of the trunnion mounting holes on the underside of my table is stripped.

It's not hard to do. Go to a specialty fastner store and get a Helicoil kit for the correct thread size. It should come with the tap drill, special tap and install tool (plus the inserts). Then all you need to do is drill out the stripped hole, tap hole, insert Helicoil just below flush, break off the tang on the insert and you are good to go. (Word of warning: DO NOT EVER run a tap into a Helicoil, as it will bind up and you will break the tap trying to remove it.)

[billmayo]

I have been buying threaded inserts from http://www.mcmaster.com/
Type in threaded insert in the search box.

You need a special tap for helicoil and an insertion tool.

I find the Self-Tapping inserts works well in aluminum. I only use stainless steel self tapping inserts to prevent rusting and seizing on the bolt later. An allen wrench can be used to install some of the inserts. I use a bolt with a nut to install some of them. I use the permanent LocTite on them when installing. Only problem is buying more than you need at the time but they are not expensive.

Does anyone have any experience with using inserts to fix stripped threads? One of the trunnion mounting holes on the underside of my table is stripped.

[fturner]

Thanks for the advice.

[cdmclain]

I was doing some needed clean up, maintenance and alignments on the Mark V. I picked up a dial indicator to do some fine tuning of the table alignment and was surprised even though I did the alignment several times as indicated in the manual, it was "way" out of alignment using the dial indicator. Eventually, the table was finally aligned, within .002 and as I was trying to do the final tightening of the table bolts, they just wouldn't tighten. Took them out to take a look and most of the aluminum threads were wrapped around the bolts. I first thought that only two were stripped, but after I turned the table over to examine the damage, three were stripped and one was really close to being stripped. I would assume that the holes were mostly stripped when I purchased the SS used but I am sure that I contributed making them unusable and in need of a fix.

I went to the forum first and did some searching and I found this thread discussing the same issue which gave me a picture of conceptualIy what I needed to do. I then put in an emergency email to Mr. Bill Mayo, who had contributed to the solution of the thread. I asked him to expand on his initial discription and to provide a list of exactly what he suggested to be used. In short, I needed to order a certain size drill bit, tap and stainless steel threaded inserts. Probably lots of sources for the previous listed items, but he suggested and I ordered from McMasters-Carr, they were great. So, in concept, I only needed to drill the table holes out, tap the holes and make them ready to screw in stainless steel threaded inserts with a application of permanent loc-tite. Also put in some time on the internet researching tapping aluminum, threaded inserts, etc. Mr. Mayo's instructions described using his SS to do the drilling and using it, not plugged in, to tap the hole. My issue was, I could not figure how to use my SS since I was having to repair the main table. The "light bulb" would come on later.

Sorry for the poor quality of the photos.
Photo 1: My SS main table on my rolling shop cart. ( It helped that I did not have a drill that would accept the bit due to the bit diameter, it made me think about this more. That was the light bulb, maybe a little dim, but it came on.) I used the shop cart to support the main table as I did the repair work. I checked for level and plumb the best I could locked the cart wheels, clamped the main table and just went to work.

Photo 2: The tap, tap handle (Ordered the handle because I didn't think I could use the SS, but I feel that I had better control using the hand tap.) and the four stainless steel threaded inserts. A bolt and nuts to help screw the threaded insert into the tapped holes.

Photo 3: Drilled and tapped table hole. (Hard to tell what your looking at, even for me and I took the photo.)

Photo 4: Last threaded insert in place, all done.

Reassembled everything, did the table alignments, realigned everything to the realigned table and I am back in business! I really want to say, "Thank you!" to Mr. Bill Mayo, I could not have gotten this done this without him taking out the time to explain the process and making my shopping list of items. Hope this helps someone in the future.

[mtobey]

Bill Mayo may well have contributed to the longevity and pleasant use of thousands of Shopsmiths. I go to him regularly. Thanks, again Bill