Lathes & M/C tools

[ozzyo]

Been having fun playing with my lathe/milling attachment and a Bachmann Ivatt 4 chassis. I'm going to fit a High Level Gearbox and a Mashima 1626 motor and have modded the Bachmann wheels to take 1/8" axles. These will run in brass bearings with an outside dia of 3.6mm. Any suggestions how to generate a hole or slot to suit the brass bearing? I have some end mills of 2,3 & 4mm, so is it just a case of milling out wider slots in the bottom of the chassis?

 

Edit: Just found Chronos offer a 3.6mm reamer, so that may be the answer.

 

 

If it's a hole drill and ream it to 3.6mm,but if you require a slot going from the bottom of the chassis to the axle C/L get hold of a 9/64'' or a 3.5mm round nosed (ball end) end mill, set the cutter to the axle C/L and cut across the frames in .5mm or 1mm steps (this will depend how you hold your frames and how rigid your mill is) when you get near to the bottom (assuming that the hole is now 3mm) you just want to leave a witness (to only just cut the 3mm hole) then remove another .25 -.3mm.

 

If all or two of the axle holes are slots move the table the required distance, say 7' = 28mm then repeat, keeping a note of the depth index.

 

The second of the above will require that you set the chassis up so that the axle holes are at the same height from the table and that you can cut them both or all three without moving the chassis. When you move the table for the indexing keep the lead screw moving in the same direction, this is to keep the backlash in the screw and nut on the same side. As your M/C is new the lead screw and index's should be accurate for the lengths that we are talking about.

 

I hope this helps you,

 

OzzyO.

[ozzyo]

It's been a while since I posted on this thread, so some new stuff for you. A set of M/C keys for my dividing head.

Rough M/Cing the first side

This left approx .010" on the side and base to be removed

M/Cing the second side to size after the rough M/Cing

We have size

Center drilling the bolt holes, all four were done using the longitudinal index

Drilling the M5 clearance holes

Drilling the clearance hole for the Allan screw heads

Two of the M/C keys in place on the dividing head

 

Normally I would use steel for these but I had some brass stock in stock of the right size, so that was what I used. This is not the only way to do them but you only have to put the stock in the vice once this way.

 

Thanks for looking

 

OzzyO.

[Ohmisterporter]

Jobs like this are always worth doing, but you can end up spending all your modelling time making bits of workshop equipment! Nicely photographed by the way.

 

Geoff.

[Ohmisterporter]

Seeing your picture of the micrometer reminded me of an apprentice I had who took a while to get the hang uf using them. I once asked him why all his work was oversized when I measured it and correct to drawing when he measured it. "I guess I just squeeze the mic a bit more", was his reply. Suffice to say he quickly learnt the error of his ways.

 

Geoff.

[ozzyo]

Jobs like this are always worth doing, but you can end up spending all your modelling time making bits of workshop equipment! Nicely photographed by the way.

 

Geoff.

 

 

 

 

It's one of them jobs that I have been meaning to do for a while ( since I got the D/H), yes the job can take time but it saves you time in setting up the D/H.

I was on my own when I took the photos so it was down to setting the shot up and using the self timer on the camera.

 

I can remember one fellow who would use a mic. like a G cramp .

 

OzzyO.

[ozzyo]

Hello all,

 

in another post (IIRC it was about setting up chassis), you can get from Tesco's, Asda, etc a granite chopping board for about £10 that's about 12" X 10" X 3/4" that would make a good surface plate for our use. It should last a lifetime. Being granite you should have no problems with it acting as a heat-sink or any flux affecting it.

 

OzzyO.

[bertiedog]

I don't think the chopping blocks are real granite, more likely it;s Marble or resin and marble dust, and Marble does react badly to acids, it eats into the limestone content, leaving marks. The resin mix type resist acid reasonably well, due to the resin.

 

Oiling any marble first, will help if acid flux is used, the oil should a mineral oil, or grease.

 

There are also flat Slate cooking blocks, usually composition slate, a resin and slate dust mix. Old marble mantlepeices usually have a good flat source, maybe broken from a building site or building material scrap merchants.

 

Glass makes the best surface plate, short of the real thing, float glass is dead flat. Many glass merchants will have off cuts of thick grades, get them to grind the edges, or used a diamond sharpening plate to remove sharp edges.

 

Stephen.

[ozzyo]

I don't think the chopping blocks are real granite, more likely it;s Marble or resin and marble dust, and Marble does react badly to acids, it eats into the limestone content, leaving marks. The resin mix type resist acid reasonably well, due to the resin.

 

 

 

Stephen.

 

 

 

All I am going on, is what it says on the label in that it is a Granite chopping block. It does not mention marble on the label.

 

I have not bought one for use. As I have a nice big lump or ground steel about 1" thick X 12" X 10" that I use as my surface plate.

 

OzzyO.

[bertiedog]

Thanks for the information on the granite block from Tesco ans ASDA, it should be far superior to the marble anyway. The best grade surface plates are made in solid granite, it is more stable than iron. but are extremely thick. The chopping block could be set in a wooden box to protect it, set in a bed of plaster of paris, or bedded in silicon or similar caulking sealers. Granite can be fragile if heavy stuff is dropped on it!

 

For soldering on a flat surface MDF is hard to beat, cheap and disposable after it is scarred with burns,

 

For silver soldering, Duralumin plates make a good base, they take the heat, just, and the solder will not take to the aluminium at all.

 

MDF is surprisingly accurate in 12mm thickness, makes a temp top for the surface plate, or a protective top for milling set-ups.

 

It can also be used bolted to the milling table, skimmed with the cutter to give a true surface, and then have thin items like loco frames clamped of screwed to it for edge machining, where the cutter can plough through the MDF at the edge, without affecting the cutter at all.

Very thin brass can be edge machined by superglueing the brass to the MDF and popping into boiling water afterwards to retrieve the parts.

MDF can also be used in the lathe on the face plate with thin section items glued to the surface, which again can be skimmed or the centre left as a location peg if the item has a hole. Very thin plate can be done this way, we made special phosphor bronze 4 thou diaphragms this way, including rolling grooves into the thin disk, the MFF had a recess machined to match. Worked a treat.

[gerrynick]

The Amateurs Lathe by L H Sparey, available from Argus Books.If you break a tool on a lathe it is liable to go "ping" around your ears. The same occurrence on a milling machine will see the broken tool sitting quietly on the workpiece.

I have a Warco Mini Lathe, also available from Clarke Tools and Chester Tools with a different paint job and minor differences in spec. Make no mistake, these Chinese lathes are up to the mark as far as precision goes.( even Myfords are now made in the Far East) If you want something that is even more prcise, then you will need to look to the Swiss, and pay a LOT more money! I also possess a VMC mill that is far in excess of the needs of a small scale modeller.....but I can still make it grunt with a heavy cut!

As for milling in a vertical slide on a lathe, you'll need a decent size lathe to be able to do this. Most vertical slides mount on the saddle, so the only feed is via the leadscrew.....not conducive to success! I tried it on my lathe, and gave up, even after modifying the slide for greater versatility in workpiece holding.

If all else fails, contact your local model engineering society, as most of them are railway enthusiasts, and will be pleased to be of assistance with most of our needs in this area will be small jobs needing only a minimum of material and time.

With regard to tooling and supplies, I have had good service from Chronos and Folkestone Engineering Supplies.

 

gerrynick

[57xx]

I've used Chronos for quite a few items for my Warco Lathe/mill combo, always a good service. Also RDG Tools have always been good for me.

[richard_t]

Tracy Tools website has had a nice upgrade: http://www.tracytools.com/ I now seem to be able to find what I'm looking for!

 

No connection, other than a happy website browser (soon to be customer)

[Horsetan]

....Next part, making a profile tool or using a commercial profile for re-turning or tyre replacement.

 

Stephen:

 

I think I missed this - I looked through the subsequent pages on this topic and didn't know whether you'd given that lesson to us or not!

 

I wanted to learn how to make form tools for P87 profile tyres.....

[ozzyo]

Stephen:

 

I think I missed this - I looked through the subsequent pages on this topic and didn't know whether you'd given that lesson to us or not!

 

I wanted to learn how to make form tools for P87 profile tyres.....

 

 

Hello Horsetan,

 

I don't think he did, as I would like to know how to make accurate profile tools without any tool room equipment.

I suppose you could make one out of carbon steel (or silver steel) by hand and then harden it.

 

OzzyO.

[buffalo]

There is an article on making your own wheels on the MMRS site which includes making a form tool using hardened silver steel. I haven't tried it, mind.

 

Nick

[Horsetan]

There is an article on making your own wheels on the MMRS site which includes making a form tool using hardened silver steel. I haven't tried it, mind.....

 

That looks useful.

 

Would be nice to have Stephen's preferred method of making form tools as well.....

[ozzyo]

There is an article on making your own wheels on the MMRS site which includes making a form tool using hardened silver steel. I haven't tried it, mind.

 

Nick

 

 

This is the sort of thing that I wanted in this thread.

A bit of out side of the box thinking, make the wheel form true (easy if you have a lathe) then make the tool from that. The beauty is all you have to do is keep the cutting edge keen. So simple when some one else tells you how.

I had been thinking of grinding a square section lathe tool to shape.

 

Guess "who's" not a lathe hand by trade.

 

Brilant.

 

OzzyO.

[bertiedog]

First of all I did post the method before, and again yesterday on this thread, but the forum does not seem to have taken the post.

I will re-type and post again as long as this one works.

Stephen.

[ozzyo]

Hello All,

I've put on status updates about a compressor at Aldi 2.5hp, 25? L air tank, a bit noise but it does the job (it's the same one as I use for my grit blaster). Also in there is a mini drill (Dremel copy) £15. Some other bits that may be of use as well.

I've just had a look on Arc Euro Trade at a milling machine for £300 (X1L bundle) I'm tempted but I have a mill (for sale?).

 

OzzyO.

 

PS. I'm not sure if this is the right place for this but it seems to fit in.

[bertiedog]

For wheel profile form tools for 4 mm, and 7 mm wheels, you need to make a master wheel of the correct profile to the required standards in a heat treatable steel like silver steel or tool steel. The NMRA , S4/P4, DOGA, etc., publish profiles . Copy as closely as possible on the master wheel disk.

 

This master tool is made in a size to suit your lathe from 1 inch to 2 iinch diameter in Silver Steel bar or in plate cut to disks in the lathe.

The master form must be well finished, and the width of the final wheel, no more..

 

• The steel bar should be drilled with an 8mm hole in the centre before parting off. 8mm is nominal suggestion, use a size to suit the lathe, but not less than 6mm.

• The master profile disk then has a slice, (usually a quarter), ground away, and the cutting edge finished on a fine stone or diamond plate.

• The metal is then heated to bright red heat, and plunged into water to hardenen it completely.

• It is then annealed by re-heating to straw colour, and the edge re-finished with a fine diamond plate or a fine grade arkansas stone.

• The disk is bolted vertically to the lathe tool holder, or a bar held in the tool post and the tool edge set at centre height or a touch low, never run high, it will rub ruining the tool edge and work..

The whole process is repeated with another Silver steel disk, by plunge cutting the master profile into the silver steel bar again, and with a slow speed and copious lubrication. The disk is then parted off the stock bar.

 

• The new profile tool is the hardened and tempered and the edge honed with an Arkansas stone, Japanese slip stone, or a fine grade diamond tool sharpening plate.

The new profile tool will cut mild steel and brass/nickel silver blank wheels, what it will not do is re-profile existing wheels with plastic spokes like Sharman or Gibson etc, they cannot take the strain of a single profile cut. They can be done in special rim gripping collets, or cast moulds gripped in the chuck,, but are best finished individually with light normal cuts.

 

It can re-profile Mazak wheels and soft cast iron, disk and stock brass wagon and coach wheels. and be used to make replacement tyres for driving wheels. The tool can be indefinetly re-sharpened to keep it as sharp as possible. A top rake angle can be ground on if used with mild steel, but 90 degree radial top rake usually works best, again make absolutely sure the tool is at or below the centre height, never above, it rubs and strains the work surface.

 

In use the disc must be firmly mounted to a steel bar in the tool holder, via a steel bolt through the centre, with washers to spread the load and maximise the grip of the disc to the holder, it must not move.

 

hope this helps

Stephen.

[ozzyo]

Hello All,

 

and thank to Birtiedog for his explanation of how to make a form tool for wheel treads, now go to the link in post # 273.

 

OzzyO.

[bertiedog]

To add notes , the final tool is thicker than the master disk, about three times, with the cutting area in the middle of the face.

 

The whole process can be done with Mild steel, but will need case hardening at every stage, It does make turning easier, but case hardening is a bit unpredictable in home workshop use, and you may end up with a soft tool.

 

Silver Steel is easily purchased in 1 and 2 inch bar, most model engineering suppliers will sell a length cut to order as it's is expensive, or seek out bar ends or off cuts. Make sure it is real silver steel though, or you may have accidentally used HSS, and that is too tough to turn without Carbide or ceramic cutters.

 

For Non UK members Silver Steel is "heat treatable machinable tool steel". NOT HSS tool steel, which cutters and drills are made from.

If bars cannot be sourced then cut from tool steel plates and turn the discs in the lathe as before, but you will have to make a mandrill to hold the discs.

 

If all you are making is brass wheels then Stainless Steel profile disks can be used, in 303 grade, un-hardened, but you can only cut brass, and it needs regular re-sharpening, The master disk must however be made in the tool steel to be able to cut the final profile tool.

[bertiedog]

The other Reference is OK, it shows the process, but there are issues with the order, he suggests hardening the disks before grinding away, it is easier to do this before the hardening, and touch up the edge afterwards.

 

The disk's are glass hard after plunging into water, not heat treated afterwards, so may be fragile. I would suggest that the glass hard disk is cleaned, polished and heated to straw colour to temper it, still hard but no longer brittle.

The best way is a metal tray full of sand, and the disk laid on the sand and the lot gently heated till the colour is correct.

What has changed nowadays is the cheap supply of diamond knife and blade sharpening plates, a couple of quid a set from Axminster, that will grind the edge even when fully glass hard. Cheap and they work.

 

For the very best edge, then get a real Arkansas fine grade stone for the best edge, it is smoother than diamond at about 8,000 grit, most diamond plate are 600 at finest. Japanese slip stones are made at 1000 to 5000, but are very costly. Same applies to Japanese ceramic slips.

Stephen.

[ozzyo]

Hello All,

don't forget that the larger diameter that you use will decrease your clearance rake of the tool, so adjust it to suit the metal that you will be cutting. The ones that I am now remembering had an insert of about 1/2" dia..

 

OzzyO.

[bertiedog]

In practical terms the clearance below the tip will always be quite irrelevant, as the face of the tool is a circle , with the contact point on a radial line from the centre, as long as the tool tip is on, or below, the centre height, the clearance is automatically there, however big the profile cutter.

 

No tool tip is ever run above centre height without good reason, it will rub and wear the cutting tip. Some alloys do demand an above centre tool, this is a specialist use, not normal home mechanics uses.

 

For a Sieg or smaller lathe, the diameter to aim for would be about 3/4 to 1 inch, a Myford would take up to 2 inch,

Smaller sizes are awkward to use, the bolt size will be smaller and you need a massive grip from the bolt to hold it to the bar in the toolpost .

1/2 inch would be about the smallest disk size to use, with a 6mm HT bolt securing it to the bar.

Stephen