Advanced Fettling 404

[Jim Koepke]

This post will be linked at the end of the original Fettling old metal planes in the Neanderthal wisdom/FAQs Sticky.

Occasionally, the threads in the base of a plane may get stripped. Cast iron is funny that way. For repairs, I have used JB Weld since that is what is on hand. It has worked for me. Like many products, it is probably best to let it harden for at least as long as the directions suggest.

Other Creekers have suggested some products that one may choose to use, Form A Thread from Locktite and another called Belzona which has different formulations for different metals. My experience is limited to JB Weld. If these other products are better than JB Weld, then they will be awesome.

The hole was cleaned using Q-tips and lacquer thinner. The cut off nail in the picture was used to push the mixture into the hole. A layer of tape was used to get the diameter close to the drill size, #17. The tape was not overlapped. In my case, since there just happens to be some in the shop, teflon tape was used. Regular clear tape should be good enough. It may not really be needed.

Drilling.jpg

The tap is a 12-20 which is available from Victor Machinery Exchange (victornet dot com). They have a minimum order of $25 so I bought 3 taps and ground the tip off of one to make a bottoming tap. The current list price on the tap is $9.50. It is listed under HS Special Thread Taps.

WARNING WILL ROBINSON WARNING!!! If you like machine tools and such, avoid this site, you may be tempted by their close outs or other deals, DAMHINT.

Tapping.jpg

The hole only has enough depth for about four or five threads. It is probably a good idea to count how many turns you are making with the tap so you do not go too far and pull out all the new threads. Also, a starting tap will not be able to go the full depth. That is why a bottoming tap is needed. For one of those, you will need to make one from an extra tap.

After forming the threads, the oil and chips need to be cleaned from the hole and the tote bolt installed. If the threads on the tote bolt are bad, you will need to find a way to repair them before installing the bolt. I have used the multi-piece adjustable 1/4-20 dies with good results. Be careful to not over tighten the tote bolt. My method is to lightly wiggle the bolt while tightening. When the bolt doesn't wiggle any more, if it is firm in its position, then that is where I stop. I also pay attention to how many turns it has been given. The goal is to engage as many threads as possible without damaging them.

Mount Bolt.jpg

When assembling a plane, it is easiest to instal the tote before the frog.

After the plane has been assembled, it is time to test it out. Oops, this plane is making shavings left and right, but not center.

No Middle Shaving.jpg

That means the sole is convex laterally and needs to be lapped. After one fresh strip of 80 grit abrasive, the shavings are showing an improvement. They are shown as they came from the blade, left to right. There is still almost a thousandths of an inch difference in the center shaving, so more lapping is needed, but not tonight.


Getting Better.jpg

If you have never tapped threads before, this would not be a good first project. You should at least get a little instruction in the proper way to use a tap. Tapping threads also requires oil. I have used regular motor oil when tapping oil was not available, but the right oil for the job is always best.

jim

[James Taglienti]

Thanks Jim
always enjoy your pictorials and unpresuming manner

[Roy Wall]

Good info Jim........ thank you!

[Randy Bonella]

or those of us just learning all of this stuff

Thank You!!!

Randy...

[Jim Koepke]

Glad to hear others find this useful.

As I read this again, it seems a few things were overlooked.

When drilling the hole, use a low speed and make sure you are at the correct angle. I used another plane sole as a guide and had the body in the vise so the hole would be straight up and down. Originally, I was thinking of using the drill press, but that seemed like too much set up work.

The through taps come with some starting threads and do not fully form threads all the way to the tip. A bottoming tap does not have a pointed tip. To make one from a regular tap the tip has to be ground off. Be very careful doing this as heat will soften the tap and the threading area on a tap is sharp and if there is a slip when sharpening you may need band aids or worse. The metal is also brittle and it is easy to break off some of the cutting pieces.

jim

[Jim Koepke]

This plane with the tote thread repair in the original post was being used yesterday when the handle all of a sudden came loose.

So the JB weld held on for almost 10 years of regular use. Now comes the decision to see if an insert or heli-coil repair can be made or if it is time to look for another #4.

There is another type 6 #4 in the shop.

jtk

[Steven Mikes]

Jim, I suggest you try Form A Thread from Locktite next, then report back in 2030

[Jim Koepke]

Jim, I suggest you try Form A Thread from Locktite next, then report back in 2030

Maybe if some can be found.

Where can it be found?

jtk

[Tony Zaffuto]

Jim, I suggest you try Form A Thread from Locktite next, then report back in 2030

How do you use this product? Do you need a release agent on one side of the threads?

Thanks!

Curse you Jim for that metal working tool website (Victor Macinery Exchange). I see many dollars floating that way!

[Tony Zaffuto]

Maybe if some can be found.

Where can it be found?

jtk

I have successfully used JB Weld, but extreme care must be used to grease one side of the threads, and use very sparingly!

[Tom M King]

The one plane body that I rethreaded a hole in, I upsized the hole to the next closest size, which was metric. I found a metric bolt that worked. That one is still in service, probably 20 years later. I don't ever remember trying to rethread epoxy.

With short threaded holes, I start the tapered tap, by hand, with the tap held in a drill press so it stays perfectly straight. It's easy to bugger up the starting threads by hand, which in a short hole, every thread is important. If you look at sets of taps, you can see how to regrind the end on a bottoming tap. The cutters aren't exactly straight across, even on the bottoming tap. Typically, they come in sets of three-the tapered tap to start the hole, the plugging tap, which is still tapered some, but only maybe half as much as the tapered (starting) tap, and the bottoming tap to finish a stopped hole.

For holes over 3/8", I like to use an 8-point socket, and breaker bar, rather than a tapping wrench, regardless of how large the tapping wrench is. You can still go back and forth easily with a breaker bar, rather than a ratchet. The larger the hole, the larger the breaker bar you need. For example, a 30" 1/2" breaker bar, with a comfortable handle, is about minimum for a 1"-8 hole in cast iron.

A lot of mechanics like Helicoils, but you have to drill a larger hole than you would if you just upsized the threaded hole, and they're not as strong.

[Tom Bussey]

This is good information. But a better way to solve the problem is to not cause the problem in the first place. There is no reason for any screw or threaded part on a plane to be tightened to the point of stripping ( pulling out the thread) Also clean threads go together better. Care when starting the threaded part into the hole is essential.

On the other hand one can not control what other previous owners have done so your information is pertinent.

[Frederick Skelly]

Curse you Jim for that metal working tool website (Victor Macinery Exchange). I see many dollars floating that way!

Yeah. Thanks A LOT Jim! In one quick look, I already saw $100 worth stuff I "need`.

[Adam Herman]

anyone vouch for their drills?

[Rob Luter]

This is good information. But a better way to solve the problem is to not cause the problem in the first place. There is no reason for any screw or threaded part on a plane to be tightened to the point of stripping ( pulling out the thread) Also clean threads go together better. Care when starting the threaded part into the hole is essential.

On the other hand one can not control what other previous owners have done so your information is pertinent.

I wonder what effect seasonal changes have? Some well meaning fettler snugs up the tote screw during winter when his heated shop is dry as a bone. On about July the warmth and higher humidity swell the tote and put a heck of a pull on the threads. I've had it go the other way too. A plane I restored in the summer had a loose tote in the winter.