NEED HELP.. Stainless Steel bolts in Aluminum

Have you tried heat and/or cold. The two metals will react differently.

Stainless is ~1.5 timers harder than a standard bolt but can be drilled.Use a good quality high speed steel bit. The most common problem is people use a drill @ to high RPM with no lubricant. Small bits turning fast get hot quickly,especially the cutting edge melts/dulls and quit cutting. You can wipe a new bit out in 5 seconds.

Center punch,low Rpm(variable speed drill) and keep spraying with either WD-40 or a silicone lubricant ,cutting oil to keep the bit cool. If the bits flexing ,your applying to much pressure,use shortest bit possible to control flex. You may want to drill a size smaller and try a extractor or run a Tap in. If you mess up just use one drill size larger and re-tap. Say from 1/4" to 5/16". Good luck

You got it, it takes a lot of pressure and you have to keep it on to keep cuttinng or it will just spin the drill bit and work harden the SS, then you are toast. That may be the case now if you have been working on it for a long time and didn't drill it once and drill it right.

If there is enough access you can try using a thin small diameter cutoff wheel and cut a notch in the bolt similar to a straight slot screw head, then use a large screwdriver with a wrench on it to apply a lot of torque, tighten direction then loosen back and forth with penetrant and heat (beeswax is great for this) Good luck

If you cant get the bolt out using a small cut off wheel as Marmot suggest then the key to get the bolt out is to use the proper hardened drill. I have drilled out grade 6 or grade 8 bolts with the appropriate drill. Then if you need they make a pound in insert to remove bolts that are totally frozen or have been locktited in. MSC in the US will sell the correct drills.

Hi,

A Good drill to get started in broken bolts is a Centre Drill as used on a lathe, they are short, stiff and robust enough to enable you to get a start in most broken bolts.

Another way is spark erosion- This is not a do it yourself deal but can get bolts out of most delicate items. I once bought a Mini 14 that had a broken tap in a hole drilled to mount a scope on. I took it to my local SKF Bearing Centre who did the job in a couple of minutes.

Here is a US Based Co that does it, there must be someone close to your location.

http://www.kleinindustrialservices.com/broken-bolt-removal.php

Silver Lining- Grade 6 and 8 Bolts are steel , this guy is dealing with Stainless Steel here.

K1W1, I realize that he is dealing with stainless and not grade 8. My point was that grade 8 are in fact generally stronger and a hardened material compared to stainless. Stainless in general has little carbon in it and as a result makes for a weaker bolt than grade 6 or grade 8, albeit corrosion resistant. Drilling a grade 8 hardened bolt is tougher than a stainless bolt. There are a select few hardened stainless bolts, but they are not common and would not be used to mount an inspection panel.

I believe a carbide tipped steel drill will do the task with moderate operating pressure. I am unsure if the stainless to aluminum interface will have peculiar corrosion attributes, but that is not a matter of drill integrity but rather a matter of extraction technique.

-Rick

I found this:

Corrosion risks with aluminium and stainless steel in contact

Aluminium and stainless steel together also appears to be a bi-metallic corrosion risk, from the 'nobility' table.
With this combination the affect of relative surface area on corrosion is important.

A large area of 'cathode' relative to 'anode' will accelerate the anodic corrosion. Although aluminium is anodic to stainless steel, large relative surface areas of aluminium to stainless steel can be acceptable, dependant on local conditions.
Stainless steel fasteners in aluminium plates or sheets are normally considered safe, whereas aluminium rivets or bolts holding stainless steel parts together is an unwise combination, as there is a practical risk of corrosion.

An example of the safe use of stainless steel and aluminium together is where stainless steel fasteners and hold down bolts are used to secure aluminium roadway or bridge parapet guards.
Even with no insulation between the metals, there should be little risk of corrosion.

In contrast, in a marine environment, severe localised pitting corrosion to the aluminium treads has been observed where un-insulated stainless steel bolts were used to secure the treads in place.
On the same ladder however, bolts with sound insulating washers did not show any pitting on the surrounding aluminium.

This illustrates the beneficial effect of breaking the corrosion cell by isolating the two 'dissimilar' metals in marginal cases.

It came from here: http://www.bssa.org.uk/topics.php?article=89

I wish someone would have mentioned this to Broward in the 80s

+1

Stainless steel work hardens very quickly if not drilled with what to many people seems like a bit too agressive technique. A 316 bolt will never be as hard as a Grade 8 steel bolt but if too fast a drill speed and inadequate pressure is applied it will harden beyond the ability of most hardware store drill bits to handle. The sharpening angle of the drill bit is important as well since a shallow angle will harden the chips and dull very quicky and then the material will harden.

We used to use a lot of 316 bolts into aluminum framing on submersibles because there just wasn't any other practical way to do the job and siezed bolts were an everyday event in spite of trying every kind of special sauce known to man. Removing the siezed SS fastener with a slighly larger hole saw is sometimes the best alternative if it hardens beneath the surface of the aluminum.

Installing SS rivet nuts is better than threading the aluminum in many applications.

Hi,

Well written there Marmot.

I was just trying to address the original posters request for assistance by explaining the way I have personally drilled out hundreds of broken and drilled off bolts, the drilled off bolt heads being the easiest as there is always a lead.

Too much hi tech data seem to receive a negative curve here on YF from many posters which is why I refrain posting it most of the time.

I am sure that a lot of us here know from machine school that you can oil harden a piece of steel to be able to cut a softer material after the hard but brittle stage.

Rivnuts either SS or MS are great because you only have to grind or drill the rim off and you can hammer them out. They also give a much greater depth profile and even offer a blind hole deal for thin plate apps

Whoa... hold on there, boy wonder from down under. Let's implement a new YF rule here and now. When it comes to useful, helpful and relevant information... delicately correct isn't required on this cruise. It's content that counts.

You two guys know way more than most of us about the technical and mechanical sides of yachts. Some of the stuff you write bores hell out of me because it has no relevence to what I do. However I learn from it, and on stuff that is relevent to me I learn more. Never dumb it down. If it's important to one member he/she will figure it out. The others will take what they take.

Small Parts dot com

Not exactly off-topic, but a handy source for those bits that seem to disappear in the bilge..............

This little company (it's in SoFla) continues to amaze me in the depth and breadth of their unusual hardware inventory. Not as much fun as walking up and down dusty aisles and groping thru mysterious bins, but I find that if I order 4 things, only one was what I went there for in the first place.

No counter sales, but orders are filled promptly

www.smallparts.com

Hi,

I haven't been there for 10 yrs or more but I am pleased to read they are still in business.

They were an excellent source for small metric things and could get things quickly if they didn't have enough in stock.