Pin point drill source

[bertiedog]

Does anybody know the source of half spearpoint drills, without chisel point of conventional drill type? I had a few, from clockmaking supplier who has long closed in Soho in London, but they are missing presumed lost, and I urgenty need some, I wondered if they are made commercially.

 

They are to take the standard Pin point axle used these days, the type I had before were a few degree larger than the taper, and only touched at the point.

 

I can grind a drill of this form from scratch, but also need a back up, which means matching several blanks, if they are made, it's worth while buying them in.

 

The drill point has to cut like a form tool, on one edge only, usually in a pre drilled hole done by a conventional drill at half diameter of the follow up in point drill.

 

Stephen.

[Adrian Wintle]

Would an in-situ solution like the Micro-Mark Truck Tuner work?

 

Or are you looking for drill bits?

 

Adrian

[bertiedog]

It's the drill bits to drill lost wax castings for bogie sides, and I have just found what I used before which was Swiss Grobet flat spearpoint, and the price of these and Swiss Burgeon alternatives are eye waveringly expensive. So it looks like grinding from scratch, perhaps in carbide to keep wear to minimum, it is only a small batch. Some Burgeon bits are $100 plus each.........the States seem the only source. They used to be made in the UK, but all manufacture seems to have stopped.

 

Stephen.

[bertiedog]

The truck tuner form looks interesting, a plain cone without relief behind the cutting edge, the Grobet Spearpoint was fully relieved, with rake as well, but may be too sophisticated, I will grind a 60 deg cone point and grind a cutting edge into it and see if it works.

 

The old ones, Swiss Grobet brand, that I had before, cost about 5 shillings each!! shows how long ago they were bought in Dean Street in Soho.

 

Since they are for tender trucks It really does not actually need pin points, plain polished parallel stubs would do, but all the wheels to hand have pinpoint axles already fitted.

 

Stephen.

[Coombe Barton]

So five bob in 1970 -

 

http://www.measuringworth.com/ppoweruk/result.php?use[]=CPI&use[]=NOMINALEARN&year_early=1970&pound71=&shilling71=5&pence71=&amount=0.25&year_source=1970&year_result=2010

 

Says it's worth today:

 

£2.90 using the retail price index.

£5.23 using average earnings.

[Adrian Wintle]

The truck tuner form looks interesting, a plain cone without relief behind the cutting edge, the Grobet Spearpoint was fully relieved, with rake as well, but may be too sophisticated, I will grind a 60 deg cone point and grind a cutting edge into it and see if it works.

 

The Truck Tuner is intended for fairly soft materials (primarily Delrin), which may have some bearing on its design. It works reasonably well for that (and on Lima bogies).

 

Adrian

[craigwelsh]

The Truck Tuner is intended for fairly soft materials (primarily Delrin), which may have some bearing on its design. It works reasonably well for that (and on Lima bogies).

 

Adrian

As does the similar one you get free from Ultrascale with an order. That one is basically a 1/2 cut point that has been hardened with what looks like a flywheel attached.. I have cleaned out a couple of bearings with it though too where i'd got blackening fluid in them.

[KalKat]

Have you considered using a centre drill? I use them frequently in situations like this.

 

They also lend themselves to easy modification with the advatage of a chunky shank for rigidity.

 

 

Emma

[bertiedog]

Have you considered using a centre drill? I use them frequently in situations like this.

 

They also lend themselves to easy modification with the advatage of a chunky shank for rigidity.

 

 

Emma

 

That's the trouble with all conventional drills, they leave a flat instead of a point, as the conventional drill tip is a rotating chisel point, a flat structure, unless it's a special grind like spear point, with half of the tip ground away, and that's the specialist type I am after.

 

 

Also the taper before the flat is not 60 degree to suit the pin point end.

 

A very small number drill hole, 80 or smaller will do, the bearing becomes the area just higher up the cone than the tip, with a bigger hole forming the main recess for the cone of the axle end.

[bike2steam]

Would an in-situ solution like the Micro-Mark Truck Tuner work?

 

Or are you looking for drill bits?

 

Adrian

 

A useful small tool every railway modeller should have, got mine from Chris Challis when he had his shop in Shepton Mallet, he imported them from the US, and sold very well I believe.

[Il Grifone]

The truck tuner form looks interesting, a plain cone without relief behind the cutting edge, the Grobet Spearpoint was fully relieved, with rake as well, but may be too sophisticated, I will grind a 60 deg cone point and grind a cutting edge into it and see if it works.

 

The old ones, Swiss Grobet brand, that I had before, cost about 5 shillings each!! shows how long ago they were bought in Dean Street in Soho.

 

Since they are for tender trucks It really does not actually need pin points, plain polished parallel stubs would do, but all the wheels to hand have pinpoint axles already fitted.

 

Stephen.

 

Would it be easier to replace the axles? or a bit could perhaps be made by grinding a flat on a suitable piece of rod and then a 60 degree cutting point.

 

Presumably the truck tuner is designed for NMRA 1" long axles? and would need care when used with 26mm axles.

[bike2steam]

Would it be easier to replace the axles? or a bit could perhaps be made by grinding a flat on a suitable piece of rod and then a 60 degree cutting point.

 

Presumably the truck tuner is designed for NMRA 1" long axles? and would need care when used with 26mm axles.

 

Just depends how much pressure you apply between thumb, and first finger on the left hand as you turn the truck tuner with the right (presuming your right handed) , but I've found it useful on a few stiff coach bogies.

[ozzyo]

It's the drill bits to drill lost wax castings for bogie sides, and I have just found what I used before which was Swiss Grobet flat spearpoint, and the price of these and Swiss Burgeon alternatives are eye waveringly expensive. So it looks like grinding from scratch, perhaps in carbide to keep wear to minimum, it is only a small batch. Some Burgeon bits are $100 plus each.........the States seem the only source. They used to be made in the UK, but all manufacture seems to have stopped.

 

Stephen.

 

why not just drill them for pin point top hat bearings?

 

OzzyO

[bertiedog]

why not just drill them for pin point top hat bearings?

 

OzzyO

 

Cost and the commercial bearings are either pressing with a cup bottom, or the hole has be drilled with a conventional drill, with 60 deg point, that leaves a tiny flat, the very thing I do not want.

 

Maybe there are makers that do have a true pin point, but I have rarely seen them.

 

Equally the needles ends can be very poor, especially where F.E. non magnetic aluminium axles are used with Kadee couplings in mind, I have a box of ground axles in stainless that I usually substitute.

With a pin point bearing the tip should bear only at the point, the cone should be 61 degree to work well, giving a slight clearance.

 

I have ground two special drills, different types to test, they are in silver steel, heat treated to get them really hard, and they both seem to work, a fine point, with no flat, or at least too small to measure with a measuring microscope, the bottom is under a tenth of a thou across.

 

Stephen.

[ozzyo]

Cost and the commercial bearings are either pressing with a cup bottom, or the hole has be drilled with a conventional drill, with 60 deg point, that leaves a tiny flat, the very thing I do not want.

 

Maybe there are makers that do have a true pin point, but I have rarely seen them.

 

Equally the needles ends can be very poor, especially where F.E. non magnetic aluminium axles are used with Kadee couplings in mind, I have a box of ground axles in stainless that I usually substitute.

With a pin point bearing the tip should bear only at the point, the cone should be 61 degree to work well, giving a slight clearance.

 

I have ground two special drills, different types to test, they are in silver steel, heat treated to get them really hard, and they both seem to work, a fine point, with no flat, or at least too small to measure with a measuring microscope, the bottom is under a tenth of a thou across.

 

Stephen.

 

 

Stephen,

 

the ones that I was thinking of were by Alan Gibson (I think) not a pressing but a true turning. You could get them in the wasted type as well. If you are using K/Ds you would want a bit of resistance to help with coupling up, I have not got any, so that I can check them up for you as I got rid of a lot of my 4mm stuff a few years back, but I will have a look just to check for you.

 

OzzyO.

 

Ps. if you have all this measuring gear it shouldn't be to hard to make them for your self. I would still go for a turned bearing to fit in to the frames, as you have better control of the metal quality.

[Baby Deltic]

Would an in-situ solution like the Micro-Mark Truck Tuner work?

 

Or are you looking for drill bits?

 

Adrian

 

You rotter! I just went to the link, ordered a truck tuner, then saw all the other goodies on that site and wrecked my wallet.

[ozzyo]

Stephen,

 

Stephen,

 

I have now had a chance to have a look in the workshop and I do have one or two turned bearings (Alan Gibson?) the cone has been drilled as you would want. ie that is to a true cone with no visible flat to the bottom, I used a jeweler's eye glass for this X14 magnification.

 

If you still want to make your own get hold of a H.S.S. drill blank ( Drapier or Dormer do them) and get it ground to your spec. as it will last a lot longer than silver steel that has been hardened. Or if your going for it big style you could use tungsten carbide.

 

 

OzzyO.

[bertiedog]

I am making some now, in silver steel, which heat treated is harder than HSS anyway! The problem with all materials is finish, carbide is fine but must be diamond or boron ground, and I do not have a wheel fine enough to leave a glass "finish".

 

A drill grind does not require a fine finish, all the material is machined away, and no surface is leave bar the walls, whereas with a cone the walls are left, and have to have finish.

 

I tried a diamond wheel and carbide, it produces the cone, but the finish is like the surface of a micro needle file!

 

So with silver steel the cone can be turned, not ground, and can be lapped before grinding with a very fine 10,000 grit wheel. It can even be lapped with an Arkansas stone to get a glass finish.

All nuisance work to replace the Burgeon drills.

 

There would not be any trouble making the bearings as separate items from bar, the lathe tool could form the cone instantly, but the problem is drilling lost wax castings, difficult to hold for machining in a chuck..

[ozzyo]

I am making some now, in silver steel, which heat treated is harder than HSS anyway! The problem with all materials is finish, carbide is fine but must be diamond or boron ground, and I do not have a wheel fine enough to leave a glass "finish".

 

A drill grind does not require a fine finish, all the material is machined away, and no surface is leave bar the walls, whereas with a cone the walls are left, and have to have finish.

 

I tried a diamond wheel and carbide, it produces the cone, but the finish is like the surface of a micro needle file!

 

So with silver steel the cone can be turned, not ground, and can be lapped before grinding with a very fine 10,000 grit wheel. It can even be lapped with an Arkansas stone to get a glass finish.

All nuisance work to replace the Burgeon drills.

 

There would not be any trouble making the bearings as separate items from bar, the lathe tool could form the cone instantly, but the problem is drilling lost wax castings, difficult to hold for machining in a chuck..

 

Some of your replies are a bit difficult to understand. like it can be lapped before grinding. Lapping was always used after grinding!

If the job is going to to be difficult ( the lost wax castings) to hold for drilling for bearings, I would say that it would be just as difficult to hold them for any drilling operation!

 

OzzyO.

[ozzyo]

I am making some now, in silver steel, which heat treated is harder than HSS anyway!

 

Ha bloody Ha, if silver steel is harder than HSS then why is HSS used buy the BIG tool companies for making there tool bits?

Or do you know something that the big tool makers dont know?

 

OzzyO.

[bertiedog]

quote name='ozzyo' date='15 May 2010 - 23:37 ' timestamp='1273963041' post='141104']

I am making some now, in silver steel, which heat treated is harder than HSS anyway!

 

Ha bloody Ha, if silver steel is harder than HSS then why is HSS used buy the BIG tool companies for making there tool bits?

Or do you know something that the big tool makers dont know?

 

OzzyO.

 

Sorry, but you wrong, indeed the quote "big companies" do know what they are doing..... the HSS is not harder, it is designed to retain hardness under heat better than silver steel, however Silver Steel can be brought to a greater degree of hardness than a standard HSS steel. There is a small difference between mass produced HSS tooling and specialist custom tooling, an area I have considerable experience in.

 

There are plenty of exceptions, HSS is made in many, many grades, and some can exceed common hardened "Silver Steel" or "gauge plate steel" in hardness. HSS is designed to be ground at working hardness, and is tempered to suit immediate use in the workshop.

 

But "gauge plate" and "silver steel" are specialist heat treatable steels, and harder than tempered HSS after initial hardening.

 

They are also much more brittle, almost glass like at these hardness degrees, and will not take a blow, or stand the heat generated by the cutting action of the tool edge at this extreme hardness. But they are then further heat treated and tempered to make them durable at cutting tools.

 

Ordinary, Jobbers or Engineering Drills are generally made of HSS as it is tough, as long as it does not overheat dramatically in use.They can stand heat for a while, but will soften eventually.

 

A silver steel drill is hard, very hard, and could drill better as long as no heat is incurred in use. This type of drill can work well with brass. A cutting edge in Silver steel or gauge plate can be honed and lapped to a higher surface finish than ordinary HSS,(again specialist grade HSS is made to give lapped finishing).

 

The reason silver steel is used for complex drills and form tools is the ability to easily machine the steel blank, and then harden and temper it for use. HSS plate is not suitable for all form tools, it has to be ground, and this risks losing the hardness at the extreme cutting edge, without cooling.

 

I should add I am a qualified engineer, and made and designed many tools for B.S. inspection grade work, doing Brinell and Rockwell hardness testing of steels. For quick reference try Machinery's Handbook for the relevant details of steel grades, hardness and suitability for tooling of most kinds.

 

Stephen.

[bertiedog]

Some of your replies are a bit difficult to understand. like it can be lapped before grinding. Lapping was always used after grinding!

If the job is going to to be difficult ( the lost wax castings) to hold for drilling for bearings, I would say that it would be just as difficult to hold them for any drilling operation!

 

OzzyO.

 

The reference to lapping before grinding was to the surface finish of the cone, before the cutting edge is ground on to the cone. The cone is in effect a form tool, and unless the cone is a very fine surface finish it transfers any marks to the brass bearing. The cutting edge with the boron wheel would be OK to use straight away, and any marks on the brass from the cuttting edge would be polished way by the well finished lapped finish cone.

[ozzyo]

The reference to lapping before grinding was to the surface finish of the cone, before the cutting edge is ground on to the cone. The cone is in effect a form tool, and unless the cone is a very fine surface finish it transfers any marks to the brass bearing. The cutting edge with the boron wheel would be OK to use straight away, and any marks on the brass from the cuttting edge would be polished way by the well finished lapped finish cone.

 

 

Stephen,

what it sounds like you are going to make is a 'D' bit. It will cut a 'cone' bearing and give a good finish but do you need such a good finish on the cone sides of the bearings, If you are going to have 1/2deg clearance?

Yes the silver steel can be hardened to harder than HSS but it is like using glass to cut metal. Not such a good move!

 

The points of the bearing are what you are after, I would say that the point of the axle could run in a small hole and part of the 'cone' to run on the inverted cone in the bearing. Think about a center drill, you have some clearance for the end of the center for lube. but the shaft is still supported.

 

I would still say get some quality bearings and just drill the castings, as I said if you have to drill the castings use normal drills and fit bearings, and you can shim them to suit the axle length as well.

 

OzzyO.

[Jan]

Does anybody know the source of half spearpoint drills, without chisel point of conventional drill type? I had a few, from clockmaking supplier who has long closed in Soho in London, but they are missing presumed lost, and I urgenty need some, I wondered if they are made commercially.

 

They are to take the standard Pin point axle used these days, the type I had before were a few degree larger than the taper, and only touched at the point.

 

I can grind a drill of this form from scratch, but also need a back up, which means matching several blanks, if they are made, it's worth while buying them in.

 

The drill point has to cut like a form tool, on one edge only, usually in a pre drilled hole done by a conventional drill at half diameter of the follow up in point drill.

 

Stephen.

 

Hello Stephen,

 

Would something like Ultrascale's 26mm Pinpoint axle Bearing drill fit the bill?

 

The info states that:

 

Product: 26mm Pinpoint axle Bearing drill

 

Usage: To help open up plastic based RTR rolling stock to accept a standard 26mm pinpoint axle.

 

Basic Dimensions (approx.) Size across pinpoints: 26mm

Axle Dia.: 2mm

Brass grip: 3/8" (10mm) Dia.

 

Please Note: This item is available free of charge with any order placed or if ordered on its own is available for the minimum postage rate.

 

Cheers

 

Jan