Drilling holes in blades?

[Bo’sunParticipant @bosun58570]

Not a model engineering topic, but I’m certain one of you clever people will have the answer, or a least a suggestion or two.

I want to drill 1/16″ ish holes in a 1/4″ bandsaw blade (high carbon steel with induction hardened teeth).  What type of drill bit or process would be my best option?

I’ve drilled such steel with a sharpened masonry bit before, but somewhat bigger than 2mm.

In case anyone’s wondering, I need blades for a Marples wooden bow/turning saw.

[DiogenesParticipant @diogenes]

Anneal the very ends and go at it as normal.

[DC31kParticipant @dc31k]

How many holes? Would a punch and die work instead of a drill?

You could also drill using the method that has previously worked for you and then make a bush to reduce the hole diameter.

A carbide end mill would go through it but needs ridgidity. I would also be tempted to try a cheap carbide PCB (printed circuit board) drill (£0.59 each if bought in a multiple of ten from Amazon).

[VicParticipant @vic]

I’m not sure if they go down to 1/16” but a Locksmith’s drill would do it. As would a carbide drill, but they can snap quite easily in the smaller sizes. Do let us know how you get on though if you manage to do the job.

[John HaineParticipant @johnhaine32865]

I have a set of cobalt drills for this type of job.

[noel shelleyParticipant @noelshelley55608]

I might be tempted to use the spark eroder – nothing to break ! Noel.

[JasonBModerator @jasonb]

Way too much overthinking going on here as usual. There is a big clue in the question “high carbon steel with induction hardened teeth”

I would not use anything special to drill a bit of gauge plate or silver steel so why anything fancy or even spark eroders for this bit of carbon steel.

Get out the armchairs and give it a go.

Bog standard HSS 1/16″ drill that is past it’s best and in the rough work rack and a bit blunt, equally rough Naerok drill press, a bit of Sulphur containing CT90, no punch mark to start it and no skidding about. What could be easier. Hardest thing was holding the springy blade down, holding the camera and pulling the quill down with just two hands. Not even a bit of smoke to make it look like it was hard to drill

 

[JasonB]

On JasonB Said:

and pulling the quill down with just two hands.

Maybe use only one hand on the quill and that would leave a couple free for the other tasks you mention.

[JasonBModerator @jasonb]

I did use one on the quill, other held phone and blade.

Oh and if anyone was wondering the same HSS drill also goes through Eclipse hacksaw blades.

 

[DiogenesParticipant @diogenes]

..it wasn’t you that used to come to our local market and spend all morning drilling holes in files..?

[JasonBModerator @jasonb]

Waste of a good file😉 I never did buy anthing on those type of guys.

[Bo’sunParticipant @bosun58570]

Thanks for your thoughts.  Holding the “springy” blade down shouldn’t be too difficult as the blades are only 400mm long and need to be straight for the bow saw.

Just curious Jason, but why use an old decommissioned drill bit?

Any advantage with high cobalt drill bits for this?  I ask because the blades will only be 1/4″ wide and the “heat affected zone” may be a significant portion of the blades width.

[JasonBModerator @jasonb]

It was nearest to the drill press and also illustrates that nothing special was needed. If i’d have picked up a good one then it would have been coated and split point but the example was just plain black steam tempered and normal point.

The first hole drilled on the video which is second from the right was quite close to the heat zone so I’d just try a normal drill unless you have a suitable cobalt one to hand rather than buy something that may not be needed.

[JasonBModerator @jasonb]

Seems OK near the edge too, that’s an Axcaliber blade of some sort.

[Bo’sunParticipant @bosun58570]

Thanks Jason.

[VicParticipant @vic]

I tried to drill an Eclipse power hacksaw blade a while ago and a HSS bit hardly touched it. I sharpened a TCT masonry bit and that went through ok.

Edit: Not ideal but I’ve also used TCT Glass drills for hard stuff before.

[JasonBModerator @jasonb]

Quite possibly because their power hack saw blades tend to be HSS not carbon steel with hardened teeth that the OP wants to drill.

[Bo’sunParticipant @bosun58570]

I’m in the process of ordering some blades from Tuff Saws.  I’ll let you know how I get on.

[Bo’sunParticipant @bosun58570]

Not sure what’s happened to “TuffSaws”, but e-mails to Ian John have now become undeliverable, and the phone goes to BT Call Minder.  However, I’ve now got some blades from elsewhere.

Drilling with a 1/16″ HSS/Co drill worked perfectly.  Positioning the centre punch was the awkward bit as it kept skidding on the blade.

The image below shows my Grandad’s restored Bow Saw with a new blade and retaining pins.

As an aside, the stretcher is bowed by about 3mm, presumably from being compressed over the years.  I’ve tried to straighten it by supporting each end and sitting 6 engineering bricks on it for a couple of weeks, but to no avail.  Said stretcher has been finished with Danish Oil, so steaming isn’t going to work (unless I strip the finish).  Any suggestions how else I might straighten it?  The stretcher is Beech and about 25mm x 20mm.

[BazyleParticipant @bazyle]

You should be able to bend it with dry heat but more like a hair dryer than a paint stripper. Try first what the top temperature the finish can stand – I suspect about 90C.

Nice to have feedback after some suggestions are made. I haven’t used one of these since I cut my first dovetail at school but we did have one in the Men’s Shed. Unfortunately our obsessive tidier banished it from the museum section to the ‘send to Africa’ section.

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