Member postings for Calum Galleitch

Tony, it is not that your views do not count, it is just that yours are not the *only* views that count. Moreover, taking the time to understand the world as other people see it is an enjoyable activity in its own right.

Since we're talking about dividing heads, there is an excellent series on a George H. Thomas dividing head build currently ongoing on Youtube:

https://www.youtube.com/watch?v=q57xnGpfhA8

Very well paced and explained, I thought.

I don't have much advice for finding the thing that is lost, but one of the best pieces of advice I've ever had is: when you do find it, put it in the place you first looked for it.

Bill, I have to confess ignorance! I didn't know such things existed, though it makes sense that they do.

I think for my purposes a caphead will seat happily on the cone left behind by a drill - I don't doubt my counterbores aren't perfectly in line with the screw in the cross-slide but it should be pretty close.

Having a quick look at available counterbore bits the counterbore size seems a bit large - to my mind a 13mm cap in a 15mm counterbore will look a bit spacious, and the pilot hole size seems to vary!

So this turned up during the week - very well packaged from M-Machine. I took John's advice and went for steel in the end. They were out of stock of 1"x5" or 120x25mm, so I took a piece of 360mm x 3/4"x5" which fits well with just a couple of mm overhang on the sides of my cross-slide. I'll use 6 M8 cap screws to mount it.

I took my lathe to bits (again) and started plotting out where to put the screws. The thinner shell at the back is still about 12mm, so I think plenty for a 1.25 pitch thread to hold onto. At the other end, those of you who have this lathe or something similar will spot the deliberate mistake...

I spotted it as well, but not until after I'd congratulated myself for avoiding the opportunity to drill through the gib:

The problem of course is that the circular T-slot will be fouled by the location of that screw on the left. However, as I was yet to realise this, I went ahead and punched for the drill:

You can just see the circular slot through the smaller hole on the left of the large compound locating hole. I turned the slide over to check, and said some very un-ladylike words. Some gentle attention from a Dremel and a grinding bit removed the burr from the punch, and I moved the hole somewhere more sensible.

And so over to the drill press. I could have just about got it in the vice but it seemed more trouble than it was worth. I have to admit I'm not a fan of this table - I'd prefer a piece of plate with through holes/slots. This thing gathers clart and small tools like no-one's business and the T-slots are fiddly (and the top section too thin - I've broken a chunk out already). I often find myself just clamping stuff down with the G-clamp.

Six holes of swarf later:

Then transfer punch the holes to the steel plate:

And drill out the steel plate for M8 thread clearance:

I hadn't thought about the fact the socket heads are 13mm in diameter, and I don't have a suitable clearance drill. I tried counterboring one hole with a 13mm drill, in the hope runout might win the day, but no. At this point I also realised (a) I had forgotten to drill clearance holes for the compound T-nuts (T-bolts?) , so did that, and (b) that although 3/4" thick steel is nice chunky stuff, it's still not enough to properly clear the bolts! I don't think it'll be a major problem, and if in the end I have to remake it in 25mm stock, well.

A 13.5mm drill to counterbore is in the post, as is (still) a set of M8 taps, so we're not quite done, but we're well on the way now.

The dimension across the flats is 13.5 (all in mm).

The original nuts had a 30mm shank; I made mine 33mm and they fitted neatly.

The only noteworthy thing about making them, perhaps, was the small taper which provides clearance to install the nut - this is an awkward angle to cut with the compound, so I swung it round the other way and ran the lathe in reverse with a tool held like a boring bar. That and a healthy workout with the file to make the flats!

I've been working today on my fixture plate in this thread:

https://www.model-engineer.co.uk/forums/postings.asp?th=177296

which I will update separately, but as I also managed to install my replacement t-nuts today, I thought I'd add a note about them. I'm not sure if the lathe came with a stripped thread or if I managed to damage it very early on, but it's always been loose enough that the nut could be tightened so that it "jumped" over the thread, so I couldn't lock one side of the compound down properly.

Originals in black - you can see the stripped thread! As you can see the threads are not an especially tidy job - my order of operations was not optimal. I copied the original dimensions except for making the overall length just a few mm longer. I'd like to say it was skill but it was more like sheer luck that the end result sits pretty neatly:

I'll add a quick sketch with dimensions just in case anyone ever finds it useful.

Not to teach anyone how to suck eggs, but just in case: taps come in several different types, one of which is a tapered "first tap" which initially sits deeper in the hole making it easier to get it straight. You can start a thread without one of these but it's definitely more difficult!

The other trick that's handy is a spring-loaded tap follower, which holds the tap in your drilling machine and lines it up with the axis of the hole.

I don't want or need to go full DRO on my lathe, but I do want to be able to drill holes with a cross-drilling fixture in the cross-slide into a workpiece held in the lathe. These things seem ideal for the job and should be more than accurate enough:

Warco, whose picture above I have, ahem, borrowed, are sold out of the 1000mm length ones and I can't find one anywhere else at close to the price. eBay doesn't seem to have such a thing under £130, and Aliexpress has something a good bit cheaper but with extraordinary shipping costs. Can anyone suggest cheaper options?

(I know I probably don't need a 1000mm slide on a ~1m bed, but it will look tidier and give me more options for mounting, and, well, easier to make a long thing shorter than a short thing long)

Anything that goes through USB will digitise on this side of the USB cable. I do use what is called an audio interface for recording instruments (mine is the cheap but adequate Behringer UM2) but any microphone sold for use with a computer shouldn't need such tricks.

I use Audacity a lot for all sorts of basic audio tasks - real sound engineers will turn up their noses at it, quite rightly, but as a glorified tape recorder replacement it's very good indeed. And crucially, it's handy for diagnosing hardware issues because you can look at the waveform and see how much signal is getting through, what the noise floor is doing, and so on.

Can we not.

A lot of microphones have a gain control knob nowadays - sometimes not always obvious!

Zoom has various clever audio settings internally - worth a fiddle.

Lastly, what happens with other programs? When you record into something like Audacity, what do you get?

For various reasons I've been meaning to take the cross-slide off and have a look, so though I would add a note about my experience here. Removing it is simple enough:

• Compound off
• Unscrew the mounting bolts for the leadscrew
• Remove the leadscrew
• Remove the two machine screws holding the cross-slide nut in place
• Undo the plate at the front covering the gib adjuster
• Unscrew and remove the gib strip
• Slide the cross slide towards you - you have to lift it slightly for clearance (note that the brass cross-slide lock is loose and will fall out easily if you tilt the slide when carrying it)

I say simple - I may be omitting one or two steps that turned out to be unnecessary!

The large hole at the bottom locates the compound, the slightly smaller hole above is to access the T-nuts that run in the circular T-slot to hold the compound (of which more anon). The very top hole is for oil, as are the two on the bearing surface. Then the remaining three are for the cross-slide nut.

The cross-slide nut itself is two blocks of brass (or bronze) pinned together with a wedge on which a grub screw in the small hole bears. This can (I have now learnt after googling!) be used to reduce backlash: tighten up one machine screw, adjust the set screw on the wedge until backlash is eliminated, then tighten up the other screw.

I successfully got the T-nuts out through the access hole. One of the threads is stripped so I need to make or find replacements - I have had a quick google and can't see anything that looks like a standard part, but fortunately I have a lathe(!)

Finally, here's a shot of the carriage without the slide for reference:

Maybe they should rename it No Hope Garage! It hasn't quite hit that height here yet, though it's a matter of time. Have to say I'm glad we have a biomass boiler. Less glad we still have the oil-powered Aga - though as it kept us going during the post-Arwen meltdown I can't say too much against it.

Welcome and sorry to hear about your situation - for what it's worth I think you're quite right to want to move it on, I suspect a lot of workshops go dark and the machinery sits and rusts until it is worthless because someone can't face moving it on, probably the last thing the original owner would have wanted.

Some model engineering clubs will offer help, usually in exchange for a cut - they may organise sales or just send someone round to offer advice, which can be well worth it for a well equipped outfit.

There are a number of dealers who will take the lot off your hands at a very unsatisfying price - this is the best route if you just want everything gone and/or the clock is ticking.

You'll get the most bang for your buck by taking the time to catalogue everything, photograph it, and sell it all individually online - but it's a painful process!

John, thank you, I was hoping you might be able to chip in! I've not yet had the cross-slide off, so that is good to know. I had assumed the cross-section would be constant all the way along.

Alan, that's beautiful looking work (as always!) I absolutely agree, a T-slotted cross-slide would be perfect. The existing cross slide has no material to spare (it's the same as John's picture, above) and I don't currently have the facilities to manufacture a complete replacement, which would require a new toolpost and possibly compound, as well. I'm sure this will be one of my first projects when I get a mill organised!

Crossposted with S.O.D. and Howard! Yes, absolutely agree it's not ideal - I just don't have the space for a mill that isn't itself a toy at the moment. At some point I'd like to do some building work to extend sideways - half the building my workshop is in is a bare earth floor former barn but the front (stone) wall will need a complete rebuild, floor concreted, internal wall taken down and a roller shutter installed (so I can bring the mill in ) but will be a while before I get there!

I did look at some kind of adaption of the toolpost but the cross-slide travel is relatively limited, so the toolpost itself doesn't quite reach the lathe centre.

Yes, my only reason for using M10 is I have about fifteen metres of stud lying around!

I do like the idea of a pre-made plate - shame the sizes don't quite match up but surely manageable. Clive, do you find 1/2" thick enough? Certainly seems like it should but I don't like to guess.

As a milling machine is not an option for the foreseeable, I'd like to undertake light milling operations in the lathe as well as other operations involving attaching things to the cross-slide. However, the cross-slide on my lathe is not big enough to consider adding T-slots. In the long run manufacturing a replacement cross-slide would be ideal, but I'd need both a big enough mill and the skills to do it!

So my thought is to make a fixture plate in aluminium which would be bolted to the cross-slide. I don't require repeatability of fixturing, I think, so the aim is purely to create a secure platform to hold things down.

The cross slide is something like 350x120mm: so my first questions are: how thick should the plate be, and how securely should it be attached, to be reasonably rigid? Recognising of course that "rigid" is a relative concept! I don't imagine myself milling to accuracies of a tenth: more like holding a vertical milling slide to make things like T-nuts or a QCTP. I was thinking that six mounting holes in total would be adequate, in the corners and half-way along.

Looking online I see I can get a bit of 16mm plate for about £35. I am thinking of an array of tapped M10 holes at say 30mm centres - does this seem reasonable? Or would it be simpler and more flexible to just drill and tap holes as and when I need them?

Tap drilling aluminium: I may be looking in the wrong places but aluminium drills in 0.1mm increments don't seem to exist. I can find an 8.8mm carbide stub drill on eBay: to go through say 16mm, will this be up to the job for say 40-odd holes?

Ketan,

This isn't a network problem - this is a problem with the computer the website itself runs on. Often such problems are temporary and go away without intervention, hence why only a couple of customers saw it. You might want to check with your hosting company.