Best way to remove broken tap

[foufou]

If you could find a slightly larger diamond hole saw, say 1/4", you might be able to create a larger hole and remove the offending item. I have small diamond hole saws but none that small. It may not even need to be diamond to cut through the stainless steel. Good luck.

[deblen]

Here is another idea : No personal experience. You could use electronic component freeze spray. https://www.amazon.com/Professional-.../dp/B000Z99ZCA

https://www.youtube.com/watch?v=LrP-E6xeJKA

[TKDSailor]

Look for Machine Shops or Tool and Die shops near you, and bring it there. They have ways... even if they do not want to take the job, they will be able to direct you to someone that will. Best of luck!

[Cowpoke]

If you are determined to keep the same hole, the acid erosion would be my choice but be prepared to spend a great deal of time with constant flushing with fresh acid. Tap extractors are a waste of time on that small tap especially if it broke coming out rather than going in.
Carbide drill in a milling machine works well if a machine shop is available.
Good luck.

[DeborahLee]

I had some LUCK using a dremel tool with several small grinding stones and lots and lots of patience.

[Zai]

Blow it out with an oxy/acetylene torch.

[US1Fountain]

Trying to weld a head of a bolt on a recessed #10 tap will more than likely end up with the head of the bolt welded to the part trying to be tapped. A carbide drill or mill works every time when done in a mill to control cut and location. Will probably chip the endmill, so you just do a quick hand sharpen on the diamond wheel and go back at it. I’m assuming the op doesn’t have access to mills, EDM’s and will be attempting with less specialized equipment. But if all else fails, it can be done very easily by a machine shop at a cost.

[Crusty Joker]

Ziggy,
Having been a marine mechanic in a virtual other lifetime, sometimes a diamond tip drill to make a dimple, then a reverse swist small drill bit at slow speeds will cause enough vibration to dislodge and back out the device. See if you can judge how far 'through' the material the thread chaser has broken and why. This may happen as they exit a surface or hit a blockage at depth. I believe I have used every suggestion here a time or two and a few others, including putting hard nails through the spaces and using lineman pliers to back out the offending item. Where I was successful, I had patience. The other item used, is the skill of a good friend with similar experience... that is what you asked for here! My mentors and friends taught me things which I needed later because of circumstance and my own negligence! Welcome to Post Graduation U. The equation of value, includes time, danger, and dollars, as well as personal risk and depth of vocabulary! Cheers and Good Luck. Keep us posted on your progress. Any photo available?

[Crusty Joker]

Just happened to think of using adhesive to attach instead of a weld. I don't think I ever tried that, but you might search on the idea. Technology has some wonderful applications we dinosaurs could find useful... My shop once used marinetex to repair the head and block of a 4-108 Perkins. That product was a high carbon product that was not on the market very long. Worked very well. Applications engineering was extremely good. btw, the British have engineered some very wonderful engines for special applications. Sure one of the guys working in a shop there has a path you could follow! ben

[Crusty Joker]

Ziggy, what is diameter of shaft? Is the part on or off the shaft? Is the prop on or off the shaft and is the boat in or out of the water? What do you have in the way of a shop and access. These are important questions I should have asked before. I just assumed that the part was off the shaft and in a vise or other device. You size boat might indicate a 1 inch to 1.5 inch shaft. I assume the shaft is stainless, but it could be some other material. It takes a lot of patience to be me. I am ADD and yes, I am a member of the Ziggy fan club! I was a wrestler and hate not having victory because I gave up too soon! McCain is and was NAVY. Always had my respect even when we did not agree! Amazing life and great family!

[Crusty Joker]

I researched on line for this part and availability is a bit sketchy and cost seems a bit high. sources seem to be direct to mftg or through bay or other online marketing... one which I assume might fit your vessel's shaft diameter was in the area of US 230.00. Incentive to play around at the vice for a few hours. Sometimes a trip to the yard or a boat builder shipwright will produce some great assistance. Maybe an experienced mechanic would like to split a few beers and bs while you let him demonstrate his vocabulary.... also freeze it with CO 2! then warm the stainless and maybe that will work for you both while you chill some ice cubes and prepare to celebrate with a single malt... ADD and possible ADHD in a senior. ben

[Terra Nova]

Unsubscribed.

[captlloyd]

Originally Posted by Kita

as a machinist I have had my fair share of broken taps. each one is an individual case. there is a thing that they call an EDM machine. it is basically electrical discharge Machining, they will burn throughthe tap...the tap is harder than anything else you can put through it,sometimes as previously mentioned you can get a good carbide End Mill and get the job done but it's not easy and will probably kill the End Mill and then you have even more problems but it can be done. the guy that said a plasma cutter is just way out of line there's no room for that! but if they drilled and tapped that part and then had it Harden they will be able to use an EDM to get there. Research EDM Machining and then find a local machine shop that has one and they will be able to save that part

X2. Your best advice here. Of course we are all assuming your cutter is off of the shaft. You can forget welding anything to it as it is broken below the threads and too small to begin with. If it is still on the shaft I would say freeing and chipping it out is your only option. Always lubricate when using a tap, especially on stainless steel, it likes to gall. If it is off of the shaft the plasmas cutter might not be a bad choice, a short blast and it’s gone.

[missourisailor]

Several assumptions here.
The cutter is off the shaft.
It is a through hole.
You don't have much more than 1/4" of the tap, in the hole.


Using a needle tip rose bud torch head, heat the tap to cherry red.
Using a straight, pin punch, just smaller than the minor dia of the hole. beat the snot out of the tap until it is driven out.


After everything has cooled, enlarge the hole to accommodate a heli-coil. Thread and install the heli-coil. Then install a new set screw.


A through hole is easy to fix. A blind hole is a PITA!!!!!

[CaptainJohn49]

You need to look at why the tap broke, once you get the old one out OR if you drill a new hole. Stainless is very hard and difficult to tap as you have found out. If you are using taps with straight flutes you need to stop there. You need the get spiral taps. The flute twists. There are several types. Get a taper spiral for general work and a bottoming spiral tap if you do blind holes. Most machine tool supplys have them. I buy mine from Fasteners Supply a national chain. The are less than $10 per tap. I think I paid about $7 each for 1/4 x 24 tpi when I needed a couple for my Flicka.

The other thing is a good cutting oil. I can’t recommend Rapid Tap enough. Small bottle is less than $5 and will last years for the DIY type. Keep the tap and hole oiled and back out the tap every half turn (after you get it started) to clean out the chips.

These two, spiral tap and good cutting oil make the job a breeze or maybe a Bf4.

I almost forgot. I sometimes I use a bulb type bellows to clean clips out of holes. You could use an air compressor with a blow gun in a shop but this is a squeeze bulb with a nozzle the fits into or near a hole and gives a nice blast of air when needed. Cloth rags also help. Paper towels, even the blue shop towels just spread around taps. Cloth is best.

Good luck, stainless can be a bitch.