Leaf spring

M

MBurks

Joined
Mar 21, 2016
Messages
272
I was going to make a marlinspike out of some leaf springs I have but I ran into a problem.

I have some leaf springs I thought I might use for fittings at some point and I started working on a rigging knife and marlinspike for my uncle.

I used 1075 for the knife and thought the leaf spring would be ok for the spike.

I heated to almost a white heat, I could see decalesence through the whole piece, and then let it cool in the forge.

It cut easily on the bandsaw, but when I tried to drill it the bit welded in place and twisted off in the steel. I assumed it was something around 5160 but now I'm thinking it might be some alloy I'm not familiar with.

No idea what they came off of, they are relatively short so I figure maybe a trailer.

Any clues or suggestions? I never planned on using them for a blade but at this point I'm thinking I might not be able to use them for anything.
 
I'd be interested in seeing your marlin spikes - being an old boat bum I used those for many years.

Since the steel cut easy with bandsaw, it should drill just fine. Did you have good bits? What rpm? Any lube?

Ken H>
 
I'll just echo what Ken said. If you could saw it, you can drill it. It sounds more like a dull bit work hardened the area you were drilling.
 
Sounds like your temp was too high. Not that it explains your drilling problem, seems like needless to anneal just to drill a leafspring, nothing special needed, take one off a car & drill thru it. They are not that hard.
Anyway, dont understand drilling to make one. Is it some kind of folding marlinspike to put in ones pocket ??
As a millwright, I know marlinspikes are 10" or longer, x .5-.75 dia tapered to a blunt screwdriver like point.
 
Ken H> said:
I'd be interested in seeing your marlin spikes - being an old boat bum I used those for many years.

Since the steel cut easy with bandsaw, it should drill just fine. Did you have good bits? What rpm? Any lube?

Ken H>
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This will be my first and will probably never see any real use, the knife probably will though. My uncle hasn't sailed in a while now.

Let's put the annealing questions to the side, it was soft enough to cut with a bandsaw .

I went through 4 bits before one seized up in it. A 1/8th went through fine, I stepped up to a 1/4 and made very little headway, changed to a new 1/4 and rounded it off, went down to a 3/16ths and rounded it off, on the second 3/16th bit it seized and twisted off.

I didn't think 5160 would work harden like that so it must be something else right? If so, I'm not going to use it.
 
Lieblad said:
Sounds like your temp was too high. Not that it explains your drilling problem, seems like needless to anneal just to drill a leafspring, nothing special needed, take one off a car & drill thru it. They are not that hard.
Anyway, dont understand drilling to make one. Is it some kind of folding marlinspike to put in ones pocket ??
As a millwright, I know marlinspikes are 10" or longer, x .5-.75 dia tapered to a blunt screwdriver like point.
Click to expand...

Just drilling to make a lanyard hole.
 
kuraki said:
OK, what RPM was the drill running at?
Click to expand...

Probably a bit too fast, it's my 3rd from lowest speed on my drill press, not sure what rpm but it's where I normally leave it mine has about 8 speeds the slowest is crawling. I probably was running a little faster than I should but not by much, and its where i normally drill metal without any trouble.

I'm at work right now, when I get home I'm going to experiment some. The thing that confuses me is the 1/8 bit went through like butter, and that was the only bit that wasn't brand new, maybe not the best bits (Dewalt I believe ) but it was night and day difference between the 1/8th and all the rest.
 
Hoss, I noticed also his "almost a white hot" heat was too high, but since the bandsaw cut the steel just fine I expected it to be plenty soft for drilling.

The 1/8" bit needs to turn a good bit faster to drill good than does a larger size bit. The 1/4" should drill pretty fast - perhaps the 1/8" work hardened the spot causing the drilling problems. BTW, some 1/2" W2 drill rod would make a nice marlinspike - already round, just need tapering on the end. Chuck in drill motor and spin while grinding on slack belt.

Ken H>
 
There are two problems here, the hardness of the steel and the speed of the drill. Harder steels require slower speeds. The band saw is not a good indicator of drill-ability.

Hoss
 
The band saw is not a good indicator of drill-ability.
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Hoss, I certainly would NEVER argue with your superior knowledge and experience - I assumed if the bandsaw would cut, then a drill would cut, but we all know about "ass-u-me"ing. {g}

Ken H>
 
DevinT said:
There are two problems here, the hardness of the steel and the speed of the drill. Harder steels require slower speeds. The band saw is not a good indicator of drill-ability.

Hoss
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Ok

I overheated because the piece was thick and I wanted to get internal temp at least hot enough, since I was using a forge I just heated up, took it out and straightened it then stuck it back in and turned off the forge.

I think I'm going to leave this stuff alone until my evenheat comes in (whenever that is) so I can control the temps.

Ken H> said:
Hoss, I noticed also his "almost a white hot" heat was too high, but since the bandsaw cut the steel just fine I expected it to be plenty soft for drilling.

The 1/8" bit needs to turn a good bit faster to drill good than does a larger size bit. The 1/4" should drill pretty fast - perhaps the 1/8" work hardened the spot causing the drilling problems. BTW, some 1/2" W2 drill rod would make a nice marlinspike - already round, just need tapering on the end. Chuck in drill motor and spin while grinding on slack belt.

Ken H>
Click to expand...
I never thought about the difference in the speed of bits, it makes sense but it never occurred to me.

Using drill rod would be perfect but I don't have any.

I considered using 1/2 inch rebar but I'm not sure of the hardenabilty, although I've heard of people making knives from it.

I don't have to be hurry so I've been kicking around some ideas. Since this is going to be a companion to a knife and probably won't see any use, I may use some 1075 and make I a little smaller than it would typically be.

I will still have to do some forging to get some thickness but it doesn't have to be a 1/2 inch thick stock to start with.

Thanks for all the replies!
 
I was also thinking of hot punching a hole and cleaning it up with a file, which is probably what I'm going to try first, although I'm still not going to harden it until my oven gets here.
 
Another problem is the drill progression you used. Drilling pilot holes is fine (though unnecessary in this case), but the pilot should be smaller diameter than the width of the chisel point of your next size drill. By starting with an 1/8" drill and going to 1/4" or worse, 3/16", the bigger drill gets undue stress out towards the lands. It's likely that the 1/4" started cutting, then rolled or chipped the cutting edge, while the 3/16" probably didn't even cut before the corner of the cutting edge and drill land rounded right over.

The 1/8 went through because while it may not have been annealed properly, it was soft enough to drill. Because it wasn't annealed properly though, it was tougher than in a complete "free machining" state. The 1/8" bit didn't "bite off more than it could chew" for lack of a better expression. Devin is right that bandsawing isn't necessarily an indicator of drillability, because the chisel point of a drill, where the surface speed is 0 and the cutting edge terminates, actually extrudes material rather than cutting it. This is where the majority of heat comes from during drilling, even with a sharp bit. But it also does a good thing, which is slow the axial feed rate and keep it steady.

Once those 1/8" holes were in, and you followed up with another (especially NEW) drill that didn't have this axial resistance, they did bite off more than they could chew. If it was properly annealed, they may have gone right through. Or they may have gone through 3 holes before blowing their cutting edge.

Drilling into an existing hole of greater diameter than the web of the drill is about the hardest operation you can put a bit through. It needs to be done slowly to work.

I can't count how many FiF episodes where someone drills holes too small or out of alignment, then tries to open them up with another bit, and then blows the corners of the drill off. Then they keep forcing it through the hole and wipe the lands right off the drill and wonder why the pin still doesn't fit.
 
I always keep a print out of a drilling speed chart taped to the drill press at work. You don't need to be changing belts for every little variation in bit size, but it will definitely help to keep it in the ballpark. Also using lubricant can really help both in the drilling and in warning you that you're running it to hard. Watch your chips and the amount of smoke coming off the lube. If you're chips are turning brown or blue and you're blowing smoke ease off. Especially with self annealed material. You never know if there's a hard spot hiding in the middle.
For where you're at in the process I would throw it back in the forge and re-anneal to get the work hardened spot out, then drill again. Or try hot punching it if you think some of the bit is still welded to the walls of the hole.
 
DevinT said:
There are two problems here, the hardness of the steel and the speed of the drill. Harder steels require slower speeds. The band saw is not a good indicator of drill-ability.

Hoss
Click to expand...

kuraki said:
Another problem is the drill progression you used. Drilling pilot holes is fine (though unnecessary in this case), but the pilot should be smaller diameter than the width of the chisel point of your next size drill. By starting with an 1/8" drill and going to 1/4" or worse, 3/16", the bigger drill gets undue stress out towards the lands. It's likely that the 1/4" started cutting, then rolled or chipped the cutting edge, while the 3/16" probably didn't even cut before the corner of the cutting edge and drill land rounded right over.

The 1/8 went through because while it may not have been annealed properly, it was soft enough to drill. Because it wasn't annealed properly though, it was tougher than in a complete "free machining" state. The 1/8" bit didn't "bite off more than it could chew" for lack of a better expression. Devin is right that bandsawing isn't necessarily an indicator of drillability, because the chisel point of a drill, where the surface speed is 0 and the cutting edge terminates, actually extrudes material rather than cutting it. This is where the majority of heat comes from during drilling, even with a sharp bit. But it also does a good thing, which is slow the axial feed rate and keep it steady.

Once those 1/8" holes were in, and you followed up with another (especially NEW) drill that didn't have this axial resistance, they did bite off more than they could chew. If it was properly annealed, they may have gone right through. Or they may have gone through 3 holes before blowing their cutting edge.

Drilling into an existing hole of greater diameter than the web of the drill is about the hardest operation you can put a bit through. It needs to be done slowly to work.

I can't count how many FiF episodes where someone drills holes too small or out of alignment, then tries to open them up with another bit, and then blows the corners of the drill off. Then they keep forcing it through the hole and wipe the lands right off the drill and wonder why the pin still doesn't fit.
Click to expand...

Makes sense.

I've been working with wood too long.
 
kuraki said:
Another problem is the drill progression you used. Drilling pilot holes is fine (though unnecessary in this case), but the pilot should be smaller diameter than the width of the chisel point of your next size drill. By starting with an 1/8" drill and going to 1/4" or worse, 3/16", the bigger drill gets undue stress out towards the lands. It's likely that the 1/4" started cutting, then rolled or chipped the cutting edge, while the 3/16" probably didn't even cut before the corner of the cutting edge and drill land rounded right over.

The 1/8 went through because while it may not have been annealed properly, it was soft enough to drill. Because it wasn't annealed properly though, it was tougher than in a complete "free machining" state. The 1/8" bit didn't "bite off more than it could chew" for lack of a better expression. Devin is right that bandsawing isn't necessarily an indicator of drillability, because the chisel point of a drill, where the surface speed is 0 and the cutting edge terminates, actually extrudes material rather than cutting it. This is where the majority of heat comes from during drilling, even with a sharp bit. But it also does a good thing, which is slow the axial feed rate and keep it steady.

Once those 1/8" holes were in, and you followed up with another (especially NEW) drill that didn't have this axial resistance, they did bite off more than they could chew. If it was properly annealed, they may have gone right through. Or they may have gone through 3 holes before blowing their cutting edge.

Drilling into an existing hole of greater diameter than the web of the drill is about the hardest operation you can put a bit through. It needs to be done slowly to work.

I can't count how many FiF episodes where someone drills holes too small or out of alignment, then tries to open them up with another bit, and then blows the corners of the drill off. Then they keep forcing it through the hole and wipe the lands right off the drill and wonder why the pin still doesn't fit.
Click to expand...

I think you're right and that's the problem .Another thing , over the years I use many leaf spring for making a variety of things .And I have never problem to drill hole in them .Some leaf spring I use was more then 1.5cm thick .I think that no matter which tipe of leaf spring is in question ..........all are under 50 HRC , and they don t need to be anealed to drill hole .........
 
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