A couple of weeks further on and the lathe has started to get used but I have still been tarting about with the last few things that needed doing.
First, the bed clamp for the taper turning attachment. This didn't look like an original fitment for this machine. It was a sloppy fit on the rear bedway, so it got a bit of attention on the mill to cut a tighter fitting slot to make the whole thing feel right:
So now the clamp will stay put on the ways even without the brass clamping cylinders - one of which was missing anyway and needed a new one making:
It got shaved further to ensure the tailstock could pass it without fouling. Not sure if this is how it would have been originally, but it'll make it more convenient:
And yes, that mark on the end of the bed was a brush bristle in the paint. It'll disappear under the dings and scratches soon!
Having changed the height if the bed clamp from milling out the bed mounting slot, the original eccentric and rod clamp block wouldn't fit, so I made new ones (3 in the case of the clamp block after 2 cock-ups!):
I put new wire in the lo-volt light and refitted that. When I started using the lathe I missed having a worklight. Originally the transformer took 440V down to 48V. I'm running it on 240V so I fitted a 24V LED bulb:
Then time to fix an annoyance. The cam which operates the microswitches which turn the lathe on and off required the on off lever on the apron to be pushed beyond the detent to get it to turn on. There wasn't any adjustment to be had so I made a new one. The old one:
Then on to the DRO. Firrtly the console. There were a couple of screw holes in the back of the headstock so I used them. Got all fancy with the mounting bracket. A simple rectangular block would have sufficed, but it looked better skinnied down:
Granted this is a cheapo DRO from aliexpress, prob half the cost of machine-dro, but it struck me how light and flimsy this one is compared to the one I bought 7 years or so ago for my mill. Every bolt has been made smaller, M8 instead of M10, and the rectangular tube the arm is made of is much thinner material. Hey ho, it was cheap.
What really annoyed me about this DRO though was the beeper. Every button press, loud enough to wake the dead. The manual suggests there's a menu option to turn it off. Nope, not there. So I used a hardware rather than a software disable option. A soldering iron and solder wick:
For the scales, the Z axis (which they call Y on this 2 input DRO console), I used the scale as supplied, made up 2 jacking plates in case it needed levelling and used two holes that were already drilled and tapped in the rear of the bed:
M4 SHCS with an M4 nut in the extruded slot in the scale mount, M6 jacking screws and an M8 fixing bolt:
The carriage already has tapped holes on the spindle side so I used these:
Much milling, drilling and faffing later and this is the mount that carries the read head:
And so to the cross slide. I mounted this on the tailstock side of the slide. The scale mounting extrusion from aliexpress was too thick so I dug out some extrusion I got when I did my mill. I'd already bought some 5um tape as I knew the scale would require messing with. I had to drill two holes and tap them M5 on the side of the slide. The scale then fits in nicely:
More brackets, again using the existing holes in the saddle and we have a sensor mounted:
Then take it all apart again as I'd forgotten to mill a cutout for the coolant mount:
The sensors I'm using have been described as "hot ****" by the guy that does the touch-dro system. Granted, they're prob not as good as you can get, but £30 vs £120 says they're good enough for me. I'm not doing model engineering after all. I checked the X axis against a dial indicator and it was within 0.04mm over a 10mm range, no errors at the extremes I tested but 0.04mm in the middle, so I'm happy enough!
I thought I'd bring this thread up to date as a fair number of things have happened since the last post.
I bought a coolant nozzle from Aliexpress. The tube that mounts this onto the carriage was banana shaped, so I drilled and split some aluminium rod to squeeze it back straight:
Then put it on the carriage:
The coolant system is ready to go, the two things missing are the filter screen in the chip tray for the coolant return and, ummm, coolant. Any suggestions as to what would be best for occasional use would be welcome.
The Ainjest rapid threading attachment got the full treatment. It started off looking like this
and got a full strip down, clean, paint and reassembly. This is it in bits during the clean:
During the stripdown the wear on the gear and half nut became apparent:
The half nut isn't too bad but the gear was getting a bit sharp, so I made a new one. As I fancied a Harrison threading dial (more on that in a mo) I made a gear for that at the same time. As these gears engage on the 4TPI leadscrew they have a circular pitch of 0.25", and a helix angle of about 4 degrees. For this I used my gear cutting attachment on my Elliott 10M shaper:
The pics are of the aluminium test gear, before I risked the small chunk of phosphor bronze I had in my stash. In this pic are the test piece, and original gear from the longbed M300 that's since been sold to @sako243, the new bronze replacement, the original Ainjest gear and its bronze replacement:
The Ainjest gear needs a pin installing but here it is test fitted on the back of the threading unit:
Its missing its securing screw too and currently is waiting for me to get round to finishing this thing off and get it installed.
And so to the threading dial. The lathe came with one that was an aftermarket unit:
There's nothing wrong with it other than it doesn't fit on the apron without the Ainjest and its adaptor plate, plus it's got gearing inside that I don't need and, well, I just fancied a Harrison style one like the longbed has. There was one on ebay at a cool £130 for a beat up example, no thanks, so whilst I still had the longbed in the garage, I borrowed it to measure up and make my own. So, with the clock ticking before the longbed got collected I set about milling the body from solid:
Here's the end result, the milled one obviously doesn't have the draft angles on it:
I copied all the other parts from the original, including the straight knurls nuts which I arranged the shaper to cut automatically:
The data plate on the front was made by using laserjet toner transfer paper to get a scan of the original onto aluminium. For the dial on the top a set of 6mm number punches sufficed:
I decided to paint the body to match the rest of the lathe, it's currently drying:
The original has now departed to it's new home with the longbed lathe. Fortunately this one works fine.
Everything had been going far too smoothly. The lathe has been put to work and is getting dirty and the paint chipped. However, I had a metric threading job to do, internal into a blind hole, so I planned to run the lathe in reverse with the tool cutting on the back side of the hole. I wanted to run the lathe in its low speed range at 125rpm, but the most awful rattly banging noises came out of the headstock. Job on hold, time to investigate.
Having peered long and hard and worked out which pair of gears was causing the issue, I discovered this delightful sight:
That little chip in the gear. For closer inspection and remedy it had to come out as its at the bottom of the headstock (well, it would be!). To get this shaft out, half the headstock gears, including the spindle, have to come out:
Close inspection of the gear (it's integral to a shaft, part 302-021 in the manual) revealed a small burr which I'm guessing was raised when a bit of tooth broke off and got squeezed in the gears. Oh joy! I used a new slipstone to remove the burr and make sure the tooth was smooth:
While it was out I measured it up in case I decide to have a go at remaking one:
The fly in the ointment regarding making one is that the headstock, like the threading QCGB, is full of profile shifted gears. Easy to do on the shaper, the difficult bit is deciding exactly what the profile shift is.
The good news is that when reassembled it ran quiet. Well, as quiet as a straight cut gear train runs! So finally I could get back to the job I was tring to do in the first place:
The chuck in the pic is a new one that I invested some of the proceeds from the sale of the longbed M300 in. I let the best 3 jaw go with the longbed. The other 3 jaw I had was only good for a welding positioner as the jaws are badly unevenly worn. Yes, you can regrind them but that involves another dozen projects to get set up with no guarantee of success. This chuck is a Vertex one, clearly built to a price. First thing I did to it was to strip it, clean it and apply a slipstone to the unground gear teeth:
I machined the backplate from the old chuck to accept the new one. The register required was a bigger diameter (it would have been too easy otherwise) and I couldn't face off too much as the camlock studs would have got the chop too:
On the first runout test, measured at the chuck and 100mm further out, a silver steel rod I use as a test bar ran out by 0.02mm. For once, something went right!
@RobCox very impressive work, particularly like the thread unit. Always fancied a taper turning attachment and Ainjest but when they appear they go for wedge.
When I thin things out and get the workshop back in order they are on "wish list"