Two Questions - Drilling Hss & Lathe Lubrication.

[Robbo3]

Two Questions - Drilling Hss & Lathe Lubrication.

How can I drill rivet holes in an industrial hacksaw blade which is presumably either hardened or high speed steel?

Some years back I made a narrow parting tool from a piece of blade from a recipricating hacksaw. After grinding a tang I made a conventional round handle to suit.

Having offered to make another one with flat sided handles for a friend, I realised that I only have HSS drill bits & they won't touch it. Hence my question.


Lubrication Points

My lathe, a Draper WTL-90, the type with split pulleys, has lubrication points that are spring loaded ball bearings, inset so as to be flush with the end of the shafts. Working on the principle that any lubrication is better than none, I have always used an oilcan with a nozzle & a heavyish oil. The problem with this is that if I overdo it, oil gets thrown everywhere.

Another friend has suggested that I should be using grease instead of oil but could offer no solution as to how to get the grease into the shaft. My knowledge of grease guns is limited to, that they have a nozzle which pushes over & clips onto a grease nipple, which obviously it can't do in this case.

I have seen cone nozzles which screw on, I presume, in place of the standard nozzle. Is this what is required to grease this type of lathe?

The manual for the lathe makes no mention of there even being lubrication points, let alone how to go about it,
- http://www.drapertoolbox.co.uk/link/1/63938ins.pdf

So if grease is the correct lubricant, what type should it be & what equipment is needed to apply it?

Regards

Robbo

 

[paulm]

On the hacksaw blade question, cobalt drills and cutting compound/lube might get through it, but otherwise you would need to heat the handle end of the metal blank with a blowtorch until orange/red and allow to cool which will "unharden" it and make for easy drilling.

There are more experienced metal bashers out there than me though so I stand to be corrected

Cheers, Paul

 

[Roger C]

Robbo 1 Try using a tungsten bit that is sharpened and at very slow speed with water or a cutting liquid and very little pressure. 2 Most blade are HSS +-18% 3 Cut a slot in with a small angle grinder and a thin disc, one from say the teeth side an one from the other side spaced say 25mm / 1" apart can be more.
A small grease gun will do they have nozzles that fit over the grease nipple. Wheel bearing grease will do

Regards Roger

 

[CHJ]

paulm has the right approach with the blade, heat to soften, clamp the major part of the blade in something that will absorb the heat such as metal vice jaws to avoid wrecking the temper of the working end, if you limit the heating to the minimum length required to get the fixing there should be enough hardened (bend resistant) blade left in the handle to allow use without having to re-harden and temper the drilled section.

On the lubrication front all you need is a small push to pump grease gun, they normally come loaded and last years before needing refill, it it does not come with alternate needle type nozel just make sure you hold it square on to the ball fitting to reduce leaks.-
<<< linky pic.

 

[boysie39]

On the question of the parting tool ,why not fit the handle as you did before and plane to shape :?: :?: simples.

 

[CHJ]

On the question of the parting tool ,why not fit the handle as you did before and plane to shape :?: :?: simples.

Eugene, with a thin flat blade it is safer to have the whole blade width sandwiched in a wooden handle, a reduced tang is more likely to twist or snap off in use.

 

[TEP]

Small grinding stone if you have one of these mini-tools, best way IME for the odd hole, keeps the temper in all the blade. (Although mine is made from a full length machine 1 1/4" hacksaw blade. I don't use any handle on it. Just use the blades as is) Or carbide drills or burrs if doing a production run.

 

[János]

Hello,

Drilling hardened HSS is a wasting of time and effort, as the stuff is at HRC 63 (very hard). Annealing the tang might be a practical solution, but many HSS types are air hardening, so annealing them properly is not that easy, especially in thin sections. And a badly annealed tang may break or bend in use. Try and take your blank to a water jet cutting or laser workshop, they could bore trough it easily.

Have a nice day,

János

 

[12345Peter]

When I maqde my parting tool from a hacksaw blade I had a problem drilling, so I tried touching the blade with an angle grinder and that made all the difference, the drill bit (HSS) went through without a problem.

Regards

 

[Robbo3]

Thank you gents, one & all, for your suggestions.

On the drilling front,

I have a butane blow torch but IIRC it doesn't have sufficient output to heat to cherry red.

I also have a small propane cylinder but the cost of a new torch, hose & regulator is rather too high for the odd bits of plumbing that I do. Perhaps a Mapp gas torch & bottle might be the way to go.

A solid carbide drill bit at about £5 seems to be the most cost effective solution if I can't find anything suitable amongst my mini drills.

If 12345Peter's solution worked then perhaps the blades are only hardened on the surface & not all the way through.

@ Chas - I have one of those grease gums kicking about in one of my old tool boxes. I'll dig it out & have a go. Just hope my visions of mountains of grease oozing out around the contact point or the nozzle skidding & grease shooting everywhere, aren't realised. Someone once told me it was called a pom-pom grease gun.

I will report back after I have had a chance to play.

 

[Phil Pascoe]

Butane burns at 1970c - cherry red steel is about 800c. You need a hearth of some description - a couple of fire bricks or something similar.It might be that the touch of the angle grinder was just enough to start the drill, instead of it's skating on a hard surface - I wouldn't have thought it got hot enough to soften it.
Phil.

 

[dickm]

I wouldn't have thought it got hot enough to soften it.
Phil.

... unless you were trying NOT to soften it!

A good source of fire bricks seems to be old storage heaters. I have three from Freecycle which form a really neat hearth and make brazing a lot easier.

 

[Phil Pascoe]

I wouldn't have thought it got hot enough to soften it.
Phil.

... unless you were trying NOT to soften it!

A good source of fire bricks seems to be old storage heaters. I have three from Freecycle which form a really neat hearth and make brazing a lot easier.

Presumably the op was trying to soften it, in order to drill it?

 

[chipmunk]

Hi Robbo,
A spear-point TCT tile drill will drill HSS.

Use plenty of lubricant and a dimple made with a Dremel will help the tile drill to bite but it'll go through ok. I've used this method to drill 5mm holes in 3mm thick HSS and one tile bit will drill about 3 or 4 holes before it chips.

HTH
Jon

 

[tomthumbtom8]

Dremel with a diamond tip would be my first bet

or even a grinding stone in a Dremel lets think about it. How are you going to shape it after you've mounted it in your handle ??

on a grinder that use a abrasive wheel

TOM

 

[chipmunk]

Hi Tom,
Diamonds will last no time at all with steel of any sort at high speed. It'll need to be TCT or AlOx or Silicon carbide or similar.

Diamonds are just another form of carbon which will react with the iron in the steel at any sort of high temperature I'm afraid. Diamond sharpening's only really any good for hand sharpening where the speeds are slow and the temperature is kept well down.

Having tried to use a small grindstone to cut a hole in HSS all I can say in its favour is that it works - e-v-e-n-t-u-a-l-l-y ! Tile drills are much much quicker and result in a better and rounder hole. But the small gindstones are good for marking the surface of the HSS so that the drill doesn't skate and can get started.

HTH
Jon

 

[tomthumbtom8]

Jon

Thank you for the info I'm off to find a band saw blade now as this would be a good project to do with my son over the summer holidays

Tom

 

[Robbo3]

Update.

I managed to get some grease into the shafts using a small push type grease gun similar to that depicted by Chas earlier in this thread. A bit messy, especially if you don't get the gun exactly in line but not as bad as I thought & it wipes off easily.

After a lot of trial & error I also have two holes in my HSS hacksaw blade.

My butane blowtorch wouldn't get the blade above straw colour exept for right at the end where there is an original fixing hole. I suspect that it was a combination of too small a nozzle & the vice holding the blade sucking up too much heat.

Taking various bits of advice from previous posts, I cleaned & scored the surface in the shape of a + with a small disk on the end of a flexible shaft, to create a start point for a drill.

After a touch up on a green wheel, I used a 5mm masonry TCT bit which successfully started the hole. I didn't persevere as I only needed a 4mm hole.

I tried a 4mm Bosch 5% cobalt bit. This failed to bite & I ended up over heating it, even though I used some oil as a coolant.

I then found an ancient set of David's boron drills that I bought from a DIY exhibition when they used to be held at Olympia. One of these finished the first hole & drilled the second but disintegrated on breakthrough.

A TCT spearpoint glass drill was the easiest to use but again disintegrated on breakthrough even though a piece of hardwood was used as backing.

So thank you for all your tips, We got there in the end.

Regards
Robbo

 

[Robbo3]

A few photos with apologies for the poor quality but you should get the idea.

Starting point - A piece of hacksaw blade.

This is a 2nd blade which broke when I dropped it on the floor. You can just see the small hole, drilled with a spearpoint TCT glass bit, in the corner of the smaller piece,

Back to the first piece cut with an angle grinder.

Teeth cut off. Other markings were for a tang but weren't used.

The nearly completed tool. The handle was made in two halves with one half channeled out to accept the blade. Plenty of gorilla glue & 3 stainless steel 4mm pins to hold them together.

Regards
Robbop

 

[chipmunk]

Hi Robbop,
Glad you managed to get your holes completed - the parting tool looks "the business".

I wonder whether your difficulties may be due to the small size of the holes - I never drilled holes smaller than 5mm with TCT tile drills?

The other thing I wonder is whether the hacksaw blade was M42 or some other exotic Cobalt HSS rather than good-old M2?

...but probably somewhat academic now.
Jon