johnsmachines

machines which I have made, am making, or intend to make, and some other stuff. If you find this site interesting, please leave a comment. I read every comment and respond to most. n.b. There is a list of my first 800 posts in my post of 17 June 2021, titled "800 Posts"

Tag: milling

More Crankshaft. Roughed on mill, finished on lathe.

This is the first big end bearing.  The bearing surface was roughed out on the mill (held between centres using the dividing head), then the excess  around the flanges was removed on the mill (with the workpiece held in the milling vice),  then the bearing surface was finished in the lathe.

This is the first big end bearing. The bearing surface was roughed out on the mill (held between centres using the dividing head), then the excess around the flanges was removed on the mill (with the workpiece held in the milling vice), then the bearing surface was finished in the lathe.   There is a crankshaft buried in that lump of steel.  I just have to remove all of the bits which are not crankshaft.  (apologies to Michelangelo).

Making a start on the second big end. There is a block of steel loctited in the first big end so it is not bent when the workpiece is compressed between centres while the other big ends are machined. The second big end is yet to be finished on the lathe.

Making a start on the second big end.
There is a block of steel loctited in the first big end so it is not bent when the workpiece is compressed between centres while the other big ends are machined.
The second big end is yet to be finished on the lathe.

IMG_2620

A slightly different view showing the block glued into the first machined big end, and the almost finished second big end. This is the milling machine setup.

CNC lathe tool holders.

I needed some extra toolholders for my Boxford CNC lathe, and the following photos show some of the steps in making them on a vertical mill with a horizontal attachment.

The toolpost holder is a Dickson, beautifully made, precise.  And it came with 6 tool holders.  6 should be adequate you think?  Not so.  You really need one holder for every tool that you might use, because with CNC, you want to do the CNC settings in the computer only once.  And the Dickson holders are expensive, so I made the extras.

The material for the tool holders is cast iron bar from a house wreckers yard.  The bar was 3 foot lengths of iron window counterweights from very old double hung windows.  Very cheap $5 each.  A bit porous in places, but enough good stuff to get useable 300mm lengths. Roughly cut to length in foreground, machined square behind, finished article on right.

The material for the tool holders is cast iron bar from a house wreckers yard. The bar was 3 foot lengths of iron window counterweights from very old double hung windows. Very cheap $5 each. A bit porous in places, but enough good stuff to get useable 300mm lengths.
Roughly cut to length in foreground, machined square behind, original holder bottom right.

The holders had been dimensioned and drawn up by my expert friend Stuart Tankard.

The holders had been dimensioned and drawn up by my expert friend Stuart Tankard.

This is the original horizontal machining set up.  I made each holder separately.

This is the original horizontal machining set up. I made each holder separately.

For the next batch, I got smarter, and milled 300mm lengths of the bar, and cut them up later.  You might also note that I painted the horizontal milling attachment, using Por 15 paint.  For the actual milling I also used copious lubricant fluid.

For the next batch, I got smarter, and milled 300mm lengths of the bar, and cut them up later. You might also note that I painted the horizontal milling attachment, using Por 15 paint. For the actual milling I also used copious lubricant fluid.

Using a drop bandsaw to cut off the milled blocks.  Less than 1mm clearance.

Using a drop bandsaw to cut off the milled blocks. Less than 1mm clearance.

I made about 30 altogether.  Some for centre drills, ER collets, various left right and centre insert bit cutters, and quite a few spares for the future. You say a cornucopia of toolholders.

I made about 30 altogether. Some for centre drills, ER collets, various left right and centre insert bit cutters, and quite a few spares for the future.
You might say a cornucopia of toolholders.

DSC_1664

The height setting knobs were turned on the Boxford 125 TCL CNC lathe, again designed and G coded by Stuart Tankard. The knurls were cut by Stuart on his 4 axis CNC mill.

DSC_1663 IMG_2356 IMG_2357 IMG_2358

TAPPING HOLES. BOLTON 9. (Triple Expansion Marine Steam Engine)

Today I drilled and tapped the holes for the bolts which secure the crankshaft main bearings.  I had accurately marked the bearing mounts  in the previous session (see previous photos), and calculated and recorded the DRO (digital read out) position for each hole.  So going back to that position for each step in the process was easy and quick.  The steps today were centre drilling, drilling the 3.3mm holes, and tapping the 4mm threads to a depth of 20mm.

Centre drilling is done with a centre drill bit in an accurate chuck in the milling machine.  Centre drill bits are inflexible and will not wander over the work like an ordinary twist drill bit,  The centre drilled hole is deep enough to create a chamfered edge to the hole.  All 12 holes are drilled with the centre bit, then all 12 drilled with the 3.3 mm bit, then all 12 are threaded.  The DRO positions the work within 0.005mm each time, and the repositioning is very fast, much faster than going to a position doing all 3 processes, changing the bit for each one, then moving to the next position.

The threading was done with a Tapmatic 30 tapping head in my milling machine.  See photo.  This takes about 10 minutes to set up, but the tapping process for the 12 holes then took about 5 minutes.  I use Rapid Tap lubricant for tapping, even in brass.  I guess that manually tapping the holes would have taken about the same time, but it was so satisfying to see the Tapmatic do its stuff.  I use the Tapmatic for any tapping job involving more than about 8-10 holes.  Fewer than that it is quicker to do them manually.  The Tapmatic has a adjustable clutch.  I have never broken a tap in the job using this machine.

Incidentally, I have decided to use nuts and bolts and screws and studs in preference to metric cap screws for this model.  The appearance wins out over practical expediency.  So why the metric threads for this job today?  The specified thread was 5/32″ which is 3.96mm, so I decided to go with the 4mm metric, for which I have the tools already.

 

Tapping the main bearing blocks using the Tapmatic and Tap Magic.

Tapping the main bearing blocks using the Tapmatic and Rapid Tap.

TRIPLE EXPANSION MARINE STEAM ENGINE 3

I had almost 8 hours in the workshop today.  The base plate is progressing.

 

Sheet 1 of 3

Sheet 1 of 3

Milling the main bearing housing slots

Milling the main bearing housing slots.  Using a 14mm HSS end cutter.  Ended up blunt.  There must be some embedded casting sand still

Then I spent an hour or so painting the machined surfaces with marking blue, and marking reference points and edges.

Using a Knu vice to cramp the base plate to and angle plate, and a height gauge to mark the reference lines

Using a Knu vice to cramp the base plate to and angle plate, and a height gauge to mark the reference lines

Top view of the marking out lines

Top view of the marking out lines

After machining the main bearing housings, the big end slots and the eccentric slots.

After machining the main bearing housings, the big end slots and the eccentric slots.

TRIPLE EXPANSION MARINE ENGINE 2

Reducing the width of the aluminium plate to 140mm, so it will fit into my milling vice

Reducing the width of the aluminium plate to 140mm, so it will fit into my milling vice.  The plate is clamped to an angle plate.

Squaring the ends.

Squaring the ends.

IMG_2153

The base plate bolted to the aluminium plate. Care was taken to fix the brass base centrally and parallel to the aluminium. The fixing bolts are 3mm cap screws, and the holes through the brass plate are 3mm, so even if the brass base is removed, it will go back on in exactly the same position.

IMG_2154

I finished the day by making a spur gear for my brother’s lathe.

 

The gear attached to the shaft using Loctite.  If the Loctite is inadequate, the gear can be pinned to the shaft.   In the post tomorrow, to Townsville QLD.

The gear attached to the shaft using Loctite. If the Loctite is inadequate, the gear can be pinned to the shaft. In the post tomorrow, to Townsville QLD.  The photo shows why metalworking is an unsuitable hobby for a gynaecologist.

TRIPLE EXPANSION STEAM ENGINE 1

The base casting.

The base casting.

The base of the base, machined flat

The base of the base, machined flat

The base, with 6 pillar mounting areas machined parallel & coplanar, and the crankshaft mounting blocks after an initial skimming.

The base, with 6 pillar mounting areas machined parallel & coplanar, and the crankshaft mounting blocks after an initial skimming.  Slots for big ends roughed out.  2 hour first machining session.  2998 hours to go?

After carefully examining the base casting, and scrutinising the plans to discover all of the dimensions of the base, I commenced machining on my King Rich mill (Bridgeport clone, NT40 with DRO, an excellent machine). Since the base dimensions are scattered over 3 pages of very complex plans, and I am still relatively unfamiliar with them, I am approaching the machining with great caution. At this stage I am aiming to create some flat and coplanar surfaces, with a margin of material remaining, so I can hold the base flat, without rocking, roughing out the shape, and leaving finishing to dimensions at a later date. I intend to attach the base to a rectangular piece of aluminium, so the aluminium can be clamped or held in a vice, rather than risking damaging the brass casting.

CNC MILL 9

IMG_2068
Yesterday I cut some metal on the CNC mill for the first time.
I used one of the canned cycles built into the CNC controller, and faced and squared off a lump of brass which will be used for a hot air engine (The Ridder “bobber”).
Despite multiple readings of the manual, I got confused about which units required minus signs, and which ones the machine automatically assumed were positive and negative, and consequently, despite resting my hand on the emergency stop button in case such a contingency occurred, the head crashed straight into the milling vice, breaking 4 carbide tips and leaving a permanent love bite on the vice as a reminder of my incompetence.
After some expletives deleted, I re-entered the numbers, and next time, the machine went through its motions gracefully, purposefully, and quietly, leaving me with a nicely shiny and squared lump of brass.
It was so impressive, that I repeated the exercise, just for fun.
I had checked the squareness of the mill head to the table, and it was all within 0.01mm in 100mm, so nothing was altered.
I had bought a Z axis probe from CTC Tools in Hong Kong, and that was easy to use and accurate, for $a100.
Next step, to hook up a computer and try to download G code programs. Watch this space.

CNC MILL 8

Another day, another problem solved….
I am sure that these ramblings are incredibly boring to everyone, so understand that I am recording them for my own benefit, as a diary, as much as for the interest of anyone else who might be thinking of leaping into buying an older CNC mill.
So today I looked at the lubrication pump.
The manual says that it operates automatically on machine startup, then every 30 minutes, as long as the oil pressure is not too high. But the pump showed absolutely no sign of functioning at any time. And the ways and ball screws were totally dry until I lubricated them with an oil can.
Today I spent hours tracing wires and looking at relays, until my friend Jason S, who is a machine designer, came and had a look for me. He put a multi meter on the wires, and everything seemed intact. Then he identified the appropriate contactor (which I gather is really a big relay), and held it in, and lo and behold the pump worked. So the problem was with the pump controlling mechanism. Then Jason surmised that if he had designed the mill, he would have had the lubrication pump working only if the ball screws and ways were actually in use, not just if the machine was switched on. So next test was to watch the pump with the ball screws activated. Lo and behold the pump worked! So what was the problem? Why was the oil not coming through?
We disconnected some oil lines, and they were dry. So we manually pumped the lubrication pump until the lines filled, (i.e. primed them) and tried the lubrication system again, with the axes working, and it worked!

So the bloody manual was misleading. The lubrication system does not work when the machine is switched on. It only works when the ball screws are operating. And the machine has been out of action for so long that the oil lines had dried out.

Another gripe with the manual, was when I tried to get a canned cycle working (dry run, with no work piece or cutter). I followed the instruction steps exactly, and nothing happened. I retried, with the same result. I tried another canned cycle… same result. Then Jason arrived, and followed the steps.. same result. Then he said “what is that DATA button for? I had no idea. It is not mentioned in the manual. So we tried pushing it, and halelujah, the canned cycle worked.
So why was it not mentioned in the manual ?????
Do people who write manuals, ever test their own instructions? Or try them with an end user???
So bloody frustrating and such a waste of time.

(note added a few days later… I found the DATA key described in a different section of the manual. My mistake, it was there all of the time. If I had read the manual from start to finish entirely, and remembered the entire 150 pages – or whatever – I would not have had the problem. Silly me. )

Anyway, another step towards making some chips.

So now for the final test, the hookup with a computer using a serial port. Fortunately I have an old computer with a serial port, and I will hook it up soon.

CNC MILL 7

Z axis problem fixed!

My friend Stuart T methodically checked the wires and connections, and diagnosed a problem involving the Z axis encoder.  He  resorted to removing the encoder, to look at it more closely, and said ” that came off a bit too easily.  I wonder if the shaft is connecting properly”.  Sure enough, the shaft was loose, which explains the bizarre Z movements followed by a total loss of position information.  Someone has joined the 6mm shaft to a 1/4″ socket, and it had probably worked loose during the transport from Echuca to Geelong.

So we quickly made a sleeve to join the 6mm shaft to the 6.35mm socket, tightened it all up,  soldered a few wires which broke during the inspection, and hooray it all worked perfectly. Hallelujah.

Oh, and that $20 Chinese hand wheel.  It was 10 mm thicker than the originals, and looked out of place, so I chucked in the the lathe, and turned it down to the same 18mm thickness  as the originals.  It was made of hard plastic-bakelite material which smelled really offensive while I was machining it, and was very abrasive.  Tool steel lathe bits were just worn away, but a carbide insert tool coped OK.   The reshaped hand wheel  looks and feels much better.

Just the oil lubrication pump to fix, then I can start making chips.                                                                                                                                                                                                                                                                                                                                                                               

                                                                                                                                                                                                             

 

CNC MILL 6

Help!

I need a wiring diagram for the Extron mill.

It is a Hafco badged machine, but Hafco (Hare & Forbes) do not have wiring info.  The Extron factory in Taiwan has not replied to my emails.  Hare & Forbes apparently contacted the factory, and also drew a blank about wiring info.

That is pretty unimpressive.  The machine is only 17 years old.  In built obsolescence?  Just not worth while supporting older machines?  If it was a US or European machine there would be no problem getting info.  It seems that this Asian factory has a different idea about what constitutes support.  

Fortunately I have an expert friend who will, I am confident, be able to work it out.  

 

CNC MILL 5 with some more pics

The broken X axis hand wheel.  replacement from China for $a20, including postage....

The broken X axis hand wheel. replacement from China for $a20, including postage….

The replacement folding handle hand wheels arrived from Hong Kong today. I was slightly disappointed in the quality, but then, for $a20 each, including postage, I am not complaining. They are close in appearance to the originals.

IMG_2040

The new hand wheel fitted. On the table is a spare new hand wheel, and the broken one. I am considering machining the new one, to be closer in dimensions to the old one.

IMG_2037

This is the pneumatic draw bar motor and spring loaded engagement gear. It is now functioning!! I rebuilt a badly corroded valve, and remade a gasket, and hooray, it works perfectly. Still to replace the cover which keeps the dust out of the device. That saves $a700+ for a replacement, and gives me confidence to work on these precision items in the future. The motor behind the draw bar motor is the main spindle motor, a 6hp 3 phase motor with a very noisy fan which is another job for down the track. One thing at a time. We are getting there. I have contacted Extron Corp in Taiwan, in the hope of getting a wiring diagram, so I can look at the oil distribution pump and controller and locate the relay, which I suspect will be the culprit. It does feel good to have fixed 2 of the 5 or 6 problems with this machine.

CNC Mill 2

I was on call over the weekend, so I had today off, and spent it in the workshop. It was cold. Jumper plus oilskin cold.
I crow-barred the space for the new mill, levelled the mill with a machinists level. One foot was missing so I turned up a new one… 75mm dia, 16mm thick, with a 20mm dia recess to accept the levelling bolt.
Then I started to tidy up the awful paint job, scraping paint off the machined parts, and using my Dremel to wire brush it off plastic parts. Starting to look more respectable.
Then I found a hand wheel control lever stop made from a rolled tube which had broken off at surface level. It was hardened, as I discovered when I tried to drill it out… changed the drill bit to mush. So I used the Dremel with a carbide bit to grind it out. That worked, but it took a lot of time, and I ended up with an irregular hole which I then drilled out to 5mm and tapped 6mm. I have inserted a temporary 6mm cap screw as the stop, and it works but looks a bit gross. Needs a tidy up.
The 3 phase lead does not reach my converter, so I have to replace it with a longer one. The plug is new, so I will re-use that. I have some 20 amp 4 wire lead, so I will use that. Maybe next weekend I will get to fire it up. Saturday is out though. Geelong – Hawthorn AFL game takes precendence.
I need to make some T nuts to suit the 18mm T slots. They are bigger than any machine I have previously owned. I will tap them to accept 12mm studs, rather than the recommended 16mm studs. I already have the 12mm studs, and I cannot see that I will need the bigger ones. If i was to use the table capacity of 900kg the big ones would be useful.

TOOLREST FOR GRINDER

This contraption is a toolrest for a benchgrinder. it was an early project when I started metalworking-machining, and was made mainly on a milling machine, and lathe.
The tool to be sharpened on the grinder (lathe cutter, chisel, screwdriver, saw blade etc) rests on the top platform. The top platform can be adjusted to any angle in 3 dimensions, using the brass handles. The 2 brass knobs are to present the work to the grinding wheel, and are graduated in thousanths of an inch. Sounds complicated and it is.
Designed by Harold Hall, with plans and instructions in his book “Milling, A complete course”.
The wine glass is for scale only. Although the level went down during the photography session. Must have evaporated.
I have nickel plated several components of this tool ,because of surface rust.