Member postings for Calum Galleitch

> This is the sort of thing I'd rather buy than make

The irony is I agree with you on the principle, but for various reasons I think this one is worth tackling myself as a learning exercise (and I very much appreciate all the comments and caveats, which are a huge help). One of the things I want to make later on is a tapered reamer for chanters, which will be about 400mm long, have a taper of about 2.5 degrees, and will then need to be ground to a D section

> firmly holding the part during each machining operation

My thought was initial facing, centre drilling and OD turning in the three jaw, then between centres to cut the Morse taper, possibly back in the three jaw to drill the drawbar hole and face to length, and the rest of the machining in situ. I do need to check I can get my toolpost up that close to the spindle nose.

> machine the whole from a long rod passing through the lathe

I did think of this, the main issue being my compound only has 80mm of travel - I know with a bit of care one can overcome this sort of problem but I think it's easier not to give myself problems to start with!

> you need to check the the spindle taper runs true

Thanks John, a very good point - I think I measured the parallel section of the bore as being very close to 38mm but I will check it again. I have an MT5 dead centre on the way so that will be a useful check as well.

> If they are not ideal for milling cutters, what is their designed purpose?

My understanding is that ER collets are not suitable for high torque applications, including heavy milling. Not that I intend to be doing heavy milling in the lathe anyway!

> A purchased ER32 collet block held in a four jaw chuck

Yes, I have one of these and I considered it, but I don't want to mar the external surface, as I want to be able to use it accurately in a vice, and I definitely don't want to have to dial a tool in every time I move something (my 4-jaw chuck is excessively large, a story for another day!) I was also unsure how secure a hold such a setup would really have, though it's interesting to hear that others have done.

> How will you produce the perfectly flat-bottomed holes shown in your drawing?

I will assert they are flat, and none of you will be any the wiser :D No, the ends of the holes will be left as is, I don't think they're particularly crucial.

> there is no guarantee that the "turn down ER end OD" will remain concentric, so forming this at such an early stage is wasted work.

It creates a space for the taper to run into, meaning that as I turn the taper down I can easily measure when I have hit the big end dimension that I want, and then use that end as a reference to face the small end to length. No, not concentric, but adequate for the operations that I'll be doing with it, I think - I don't think a drawbar has to achieve perfect concentricity. I might turn that initial OD between centres anyway just for the practice of doing so.

> You will need very straight, parallel stock to run an indicator against

Quite. It was off topic but part of this exercise will be making a between centres test bar as I've never aligned the tailstock, although it is pretty good as is for the small stuff I have done so far.

> How will you check the fit of the taper?

I'm planning to use Harold Hall's "flange" method to dial in angles both for the morse taper and the collet taper - if his claims for the accuracy of the method are true then there shouldn't be much test fitting required. But taking the piece out and removing the dead centre for a test fit isn't that onerous.

> MT5 to MT3 sleeve and your existing holder

Yes, and it would probably be sensible to have a couple of such sleeves on hand. My existing holder is MT2 which feels like a big step for these sleeves. I want to make from scratch for a few reasons though - the experience of having done it (these are all skills I want to use on trickier projects), less fiddling around hunting for things (given my ability to lose things this is not unimportant...), plus (hopefully) the accuracy of the thing being made in situ.

> As a 'constructional' point, it doesn't need the 24mm hole up it - the more metal in the neck of the shank the better..

I take the point, but there's over 8mm between the bottom of the hole and the outside taper - an MT5 taper is a beefy thing! For milling I certainly don't need all that depth, but it might well come in handy at some point for other purposes.

> If you drill and tap the M10 all the way through you would make it easier to tap and you can then screw the studding in to act as a back stop.

That's a good idea - thinking about it a drawbar probably isn't ideal as a precision backstop as it will probably move when tightened a bit but there's plenty room there to run say an M6 thread down the middle. I'd probably make it adjustable from the spindle end though as my spindle is about 400mm long so getting an allen key down there might be tricky!

I'm in the process of getting set up to do some basic milling in the lathe with a vertical slide, so one thing I need is something to hold on to those pesky cutters with. I already have an ER32 collet set, so while ER collets aren't necessarily the ideal for holding miling cutters, they seem an obvious choice. I did consider a collet chuck but I have a D1-5 spindle nose, and I don't fancy making six of those cam pins, or the price of a backplate.

I have about fifteen metres of M10 threaded rod lying around, as you do, so that will be pressed into service as a drawbar. Otherwise, the part essentially designs itself: an MT5 taper, with an M10 tapped hole, an ER32 nose and taper, and some flats to grip it with.

Plan, such as it is:

• Face and centre drill
• Turn down ER end OD
• Cut taper between centres with set-over tailstock, test fit, etc.
• Drill out and tap drawbar hole
• Mounted in spindle, drill and bore
• Set up compound for 8 degree angle and cut
• Thread run-out groove and thread.
• File some flats
• ???
• Profit!

I will also need to make a washer for the far end of the spindle bore.

Should anyone be interested, my OnShape model is here:

https://cad.onshape.com/documents/5744ee595b2db9b815f92457/w/5535f6d98d9b44d7634e58ac/e/84d1b32f99a61bd45596f58f

Although the old adage is "you can make small things on a big lathe", there is a lot to be said for starting out on a smallish lathe. The 3.5" lathe was the standard hobbyist lathe for most of the twentieth century, and although 3.5" doesn't sound like much, swinging a 7" diameter part soon gets alarming, I promise! It can be quite surprising what can and has been done on such machines.

The thing about bigger lathes is that when you go from, say, 3" to 4", all the other numbers don't go up by 30%, they go up by 50-100%. Price, weight, power, danger...

There's a lot to be said for getting as big a lathe as you need, but speaking as someone who did exactly that, I will say that getting it fully equipped and doing what I want to do with it would (and will) have taken far less time if I'd curtailed my initial ambitions and gotten something smaller. On the other hand, the very small (7x14) lathes are really limited in what they can do out the box and it's questionable whether learning to deal with their inadequacies is time well spent.

The old metal v. Asian lathe debate will rumble on till the end of time and at the end of the day a well set up lathe is a good lathe, whatever its history. Old lathes now are, well, old, and perhaps sometimes fetch prices in excess of their value.

What I would suggest in your search is that you make some good notes, maybe start a spreadsheet, and think through all the different points that you and others raise, but at the end of the day, just get *something* and get started, and if in a year's time you need a replacement, you'll be that much better informed.

For what it's worth, I bought a set of ER32 collets plus MT2 holder off eBay in 2020 for £35 - it was a bit of an odd set, not a complete range of sizes with a few missing. They aren't great quality but for their purpose - workholding in the wood lathe - they are ideal. For the price I've no complaints.

For the benefit of anyone as confused as I was!

I had damp problems in my little workshop (an old stone farm building) and I seem to have mitigated them pretty effectively with an electric fan heater attached to a plug-in thermostat. It is set to run when the temperature drops to 6 degrees and stop running when it rises to 7. The fan heater itself is adjusted as low as it can go and I think runs at a few hundred watts when it is on, which as far as I can tell isn't much, especially now the temperatures here have risen a bit. The workshop feels dry to the touch now, bits of paper left in it don't feel damp and greasy.

There are inserts available for Acme threads, and if a suitable holder can be found at a reasonable price I think I'd be tempted to go this route. I've seen a few videos of people using Acme taps and in general, I like to see the machine doing the work, not me!

Thank you all. Yes, I have Ivan Law's excellent little book, and I had forgotten it went into a fair amount of detail on setup; when I read it, I was more interested in the theory side as I knew nothing about it. I see from a quick scan that my notion of mounting it on the vertical slide facing backwards isn't completely ridiculous.

The change gears are definitely Mod 2.5 - the measurements are correct, the manual says they are, and the tooth profiles match the module 2.5 cutters I bought!

On making threads, no, I don't intend to produce vast numbers, but the ones I can do are fairly constrained and I do want to be able to do some very specific ones - for example, at some point I want to make an ER collet holder to fit in the MT5 spindle, as commercial items are £££-y, and I can't pick my own thread for that! But cutting just a 33 tooth gear would open up a lot of useful sizes.

John, thanks very much for that photograph - it makes me wonder if my cover plate is 100% correct - I've still to find time to sit down and work through the rest of the calculations, but it does seem a bit strange that it calls for a 20/40 pair there and nowhere else. Also the labelling of the ABCDE gears is different from my machine which I think matches the manual.

My lathe arrived without a full set of changewheels, so one of the projects I'd like to do is to replace the missing items. According to John P's manual for the Warco equivalent, the gears should be:

26 27 28 29 30 33 34 35 36 38 41 43 45 (ones I have in bold)

They are mod 2.5, p/a 20 degrees, 6mm thick, and rotate on a splined hub.

However, the front panel of the lathe:

also has 20 and 40 tooth gears listed (and it occurs to me I should check the imperial and DP charts as well!)

Either the Warco lathe has a slightly different internal gear train or there are more ways of achieving the same thing than what is listed - quite possible with the slightly unusual setup.

So the actual list of needed gears is pending, but in the meantime I'm thinking about the making process. I've already acquired the necessary M2.5 cutters - fortunately, two cutters covers the 26-54 tooth range. I don't have the next one down, but I suppose instead of making a 20/40 pair I could make a 52 to go with the 26.

Although the lathe has steel gears, I was thinking about delrin, for a couple of reasons: cheaper, less likely to damage the cutters, less likely to damage the lathe, and easier to make. There is already a sacrificial plastic gear so I don't think there's any reason to worry about strength.

To make the splines, I was thinking of mounting the blank in the headstock and using the carriage as a shaper. Not the quickest but should be easy enough in delrin.

It's cutting the teeth (on the lathe, as I have no mill) that has me a little puzzled. I've got an HV6 rotary table with dividing plate set on the way, but I'm scratching my head a little on how to set it up. I have a fixture plate I can attach to my cross-slide, but the centre height over this is a little under 75mm. The HV6 centre height is 100mm but more to the point I don't fancy packing it up for each different blank (the largest blank, the 46 tooth, will be 120mm dia)

The other way of doing it is to mount a vertical slide (not yet acquired, alas) and have the HV6 hanging off the side of it, which I think would be safe but hardly conducive to rigidity. Everything else I can think of seems worse by comparison. Maybe having the vertical slide facing the back of the lathe rather than the headstock and mount the table vertically on it?

Edited By Calum Galleitch on 11/04/2022 14:34:16

Thanks John, that certainly all makes sense and I'll just have to do a little testing to make sure it matches up with what we expect!

I didn't realise until I'd posted that the next page of the manual lists the full transmission ratios for the various systems, so that will help in tracing what goes where.

Just on centimetres, it's not I think widely understood that the system of centi-deci-etci belongs to the metric system, but the system that we use involving millimetres and so forth is the SI [Systeme International] system, which Britain adopted in the early 60s, I think. They look very similar, and for everyday purposes are interchangeable, but there is a difference. The first chapter of Tubal Cain's handbook talks about this.

The main practical consequence of the change is that certain prefixes are no longer in official use. The definitions of certain units are also derived differently, in particular the unit of force.

I'd like to have a go at making gears to make up the missing changewheels that I have - I think I'll do a separate thread about them as it may be of more general interest but I'm just trying to understand the gear train of my lathe:

Beginning with the spindle, wheels 13,17,16,18, 19 and 20 have 45, 45, 45, 68, 17 and 45 teeth, so for one turn of the spindle A will be turned 45/68*17/45 times = 1/4 which is what John P wrote last year...so far so good!

Q. Where/how is the reverse in this diagram? Physically on the lathe it's somewhere round the wheels labelled 17-18 but unless the reverse mechanism is not drawn I don't see how it works.

In the quickchange box, 21/22/23 mesh with 29/30/31, giving ratios of 20/40, 40/20, 30/30 which corresponds with the 1/2/3 knob. Like wise the second knob, 24/25/26 mesh with 32/33/34 giving 20/40, 42/24, 36/24 (1/2, 7/4,3/2).

Finally, if the leadscrew is selected the drive is fed through wheels 36 to 28, which are 45/21.

Q. Am I right in thinking the manual states it is a 4mm pitch leadscrew? Slightly alarmingly it gives "module no. or pitch" as '4 or 1/6" '. Now 4mm is close to 1/6" but it's not that close!

Putting all this together, If I choose to cut a 4mm thread, I take A,B,C,D=36,27,28,30 teeth from the front chart and select 2,II (30/30, 36/24). One spindle revolution then gives:

1/4 * 36/27 * 28/30 * 30/30 * 36/24 * 45/21 = 1 turn of the leadscrew, so if it is a 4mm leadscrew we've got a 4mm pitch. Phew.

When the feed is selected, the 45/21 drops out and the feed rod turns.

Q. What is happening at 44/45? Clearly this is where torque is being taken off the feed. Then (assuming carriage feed engaged) 48 drives 46 which drives the wheel engaging the rack? But what are 50/51/52 doing?

Similar for the cross-feed I assume 47 engages 48, in turn driving 49.

I'll add the manual pages for the gear list to my lathe album should anyone feel inclined to try and make sense of it!

Completely correct, we haven't built anything here in Europe since the French Revolution. Every we time we start digging a foundation we get confused and have to go on strike.

What lovely looking work, John.

I think Harold later decided to use a couple of cheap magnetic bases in preference to screwing the rest down, as this lets you slide it into approximate position easily without having to set up all the adjustments.

Well, this iteration is :D

pkg's question about releasing made me realise (a) they are quite right, releasing a gentle taper would be a pest and (b) there would be practically no downforce to hold the toolpost against rotational forces. I also did the trigonometry and realised that the plug would sit about 30mm proud when the toolpost was in a relaxed state, so some redrafting will be in order, starting with a self releasing taper.

On radial location, I take the point about rotation under load, but my four-way toolpost has no locking either and in my experience so far the tool itself slips before the post does.

Yes, I wondered if it would be better at the other end - I put it at the back so it wouldn't be getting in my sightline - but in theory the toolpost should be pulling the toolholder horizontal anyway. My only puzzle is to what extent theory actually applies!

There's no radial registration (nor is there in the original design, I believe). Maybe it's my inexperience, but I don't really feel the need for it. For something that required good alignment, like a parting tool, I'd indicate in anyway, and most tool alignments aren't crucial. I do have a ratchet-type pin on my top slide although offhand I'm not sure if it's in a useful position.

As I mentioned in another thread, I have been doing some basic CAD modelling of my own version of a QCTP inspired by the MLA-23.

The dovetailed toolpost as drawn is 80mm in diameter. The hole has a 1 degree taper, matched by the internal piece shown behind in grey. The diameter of the external piece at the bottom is 55mm and at the bottom of the internal piece 56mm. So if the internal piece were to bottom out the dovetail pieces would open by just over 2mm. Of course the plan is that the toolholders will constrain the amount of opening on the order of 0.1mm.

Two questions.

One. The narrowest part of the external piece opposite the dovetail is 7.5mm. Is this thin enough that the external piece will actually bend sufficiently under reasonable force from the toolpost handle? A cantilever beam of the same length would deflect several mm under 100N of force but of course the forces here are not normal to a 7.5mm cross-section. I could (and would) alter the distance or add a groove as Alan Jackson has done in his very attractive version, but I'd like to start off in the right ballpark.

Two: Rather than have the height adjuster in the centre, moving it back allows the toolholder to be a little narrower. Is there any reason this might cause an issue? I can't see that it would, but better to know now than later!

This is not a question about the law of copyright, which I understand reasonably well. It's more about what the norms/expectations are in the world of home machining.

Specifically, I've been drawing up a few different bits and pieces in OnShape recently (a Fusion360 equivalent), and I'd like to share some of them both for feedback and in case anyone should find them useful. Specifically, they are:

• A float-lock vice (a light drilling vice)
• Harold Hall's QCTP
• My own version of the MLA-23 toolpost.

The float-lock vice I have drawn up from pictures and videos. I don't think they are made commercially and the designer has long since departed. I am fairly sure no form of legal protection exists and I would have no qualms about sharing this.

Harold Hall's QCTP is his own design, is copyrighted, and even though his design is free to download from his website I don't feel it would be right to publicly share my version without knowing his views. That said, I wouldn't feel inhibited from sharing the design with a friend or someone I was seeking advice from.

The MLA-23 inspired toolpost - although it shares the same look and operating principle as the original - is drawn from scratch, and nothing has been copied dimensionally; I have also changed the locking mechanism slightly. This is the item I feel less sure about sharing; while I don't think I would be breaching copyright, it's very clearly not my design and the designer is still selling the design commercially. On the other hand, it's a simple design and any competent machinist could knock one up from a photograph.

A lot of my thinking here is coloured by my experience of the accepted standards in my corner of the musical universe. It's normal and unquestionable for teachers to supply music to their students without seeking permissions; likewise between friends and within bands. There is however a strong culture of "buy the book" and supporting the people who put music out there. At the same time, there's a recognition that it's a bit daft to have strictures about sharing sheet music when you can simply listen to someone playing it and write that same bit of music down for yourself.