Drilling spring steel

[Spark plug]

I have been asked to upen up or slot some holes in a load of leaf springs for some seats. There like the springs that used to been seen on old tractor seats.

I have tried all the usual methods, even a carbide end mill but they are even harder than I was expecting. There’s quite a few holes to do so ideally need something that will do the job relitivly painlessly. Anyone done similar before?

 

[Wendelspanswick]

Plasma?

 

[Screwdriver]

You could try filling the hole with a TIG plug weld. That should lose the temper locally and also allow the drill bit to cut the material more slowly than trying to open an existing hole.

 

[Gritineye]

I have opened up the locating pin holes in leaf springs with a masonry drill, ground the tip angles like a normal drill but with less back relief. Worked fine in a pillar drill with oil.

 

[brightspark]

what size holes are there and what are u taking them out to

 

[rtbcomp]

You could try filling the hole with a TIG plug weld. That should lose the temper locally and also allow the drill bit to cut the material more slowly than trying to open an existing hole.

Or even a spot welder?

 

[Woody.v8]

What ever you do , keep it cool! It gets very hard very quick .
I do it on the piller drill nice and slow with pleanty of pressure using compressed air to keep the work and bit cool.
Use carbide if you can.

 

[pedrobedro]

How far are the slots going, can you drill another hole and join the two together with cuts ?

 

[Kram]

If carbide wont do it use grinder?

 

[Spark plug]

The holes are about 10mm opening up to 12mm or slotting them 1mm either way.

I was thinking about a carbide burr in a die grinder, but not sure how long the burr will last.

 

[brightspark]

The holes are about 10mm opening up to 12mm or slotting them 1mm either way.

I was thinking about a carbide burr in a die grinder, but not sure how long the burr will last.

it will last years if its a quality one and open them up in no time . my cone one has cut a lot of stainless steel fast and is still in good nick just wear gloves and goggles as the slithers come off hot and sharp

 

[Bill Edwards]

Decent cobolt drills will work great. Be aware though that even big names such as Milwaukee sell ones that aren't up to hardened metal, but good ones are available.
Plenty of lube and be aware that they're quite brittle.

 

[slimjim]

drill it using a real cobalt dril, or a carbide burr

Real cobalt drills are expensive and heavy in the hand for their size.

 

[mechman]

The holes are about 10mm opening up to 12mm or slotting them 1mm either way.

I was thinking about a carbide burr in a die grinder, but not sure how long the burr will last.

Decent cobolt drills will work great. Be aware though that even big names such as Milwaukee sell ones that aren't up to hardened metal, but good ones are available.
Plenty of lube and be aware that they're quite brittle.

Carbide burr shouldn't be a problem.

 

[Spark plug]

I have a few burr’s I’ve had for ages but been meaning to get a good die grinder. What are people’s preferences air or electric?

I used a electric bosh one and it seemed good albeit bulk’y.

 

[mechman]

I have a few burr’s I’ve had for ages but been meaning to get a good die grinder. What are people’s preferences air or electric?

I used a electric bosh one and it seemed good albeit bulk’y.

+1

 

[Kram]

What was the problem with the mill and carbide cutters? Im not sure why a die grinder with a burr would be any better? It would take forever in comparison.

 

[piman]

Hello Sparkplug,

"What was the problem with the mill and carbide cutters? Im not sure why a die grinder with a burr would be any better? It would take forever in comparison."

Exactly my thought as well, I don't believe that spring steeel cannot be machined using a carbide cutter in the mill?

Alec

 

[Bill Edwards]

I have a few burr’s I’ve had for ages but been meaning to get a good die grinder. What are people’s preferences air or electric?

I used a electric bosh one and it seemed good albeit bulk’y.

Preference is a difficult one. I would say that it's the usual thing of air giving you more power for less size over electric, if you always have air available then get a swivel coupler (£2 ish) and whip hose and it's then extremely handy.

Like everything quality varies, cheap ones are well apart from the expensive - I have a SO grinder which you can practically lean on but it just powers on regardless, without using much air. I would suggest a decent brand rather than anything bottom end.

 

[Spark plug]

I have ended up with a nice little Bosh die grinder and it’s doing the job very well, I ended up with an electric one as good name air ones are very expensive and I prefer the flexibility of an electric one if there is no air available.