Member postings for Peter Cook 6

That's what mine is. Just fitted between the chuck guard screws, and a neodymium magnet glued to the end of the rod to connect to the quill. No modifications to the mill.

OK, get the message. This was this afternoons little project. Seems to work OK.

Could some kind soul with an X1 take a measurement of the fine feed on the quill. Mine is marked as one division = 0.03mm. However one full revolution of 60 divisions gives me a total movement of 1.83mm.

The error seems to be created in a short arc. For two thirds of the rotation of the knob, 10 divisions feed down 0.30mm. For 20 divisions at one point in the rotation the down feed is 0.31 and 0.32. 

I found out when I used the feed to cut a 6.Imm deep slot in a piece of 6.25m aluminium, and the extra 0.1+ meant the bottom tore out. 

Not sure if there is a fix but 8mm aluminium on order, and a plan to fit a cheap DRO got added to the project list.

Edited By Peter Cook 6 on 12/11/2020 19:16:44

Assuming the battery is a Li-Ion You probably need something like this.

18650 Charger Protection Module 5S 10A Li-ion Lithium Battery BMS 18.5V 21V Cell | eBay

They are specific to the number of cells. 20V suggest a 5 cell battery.

You will need to get inside to connect the individual cells to the control module. If you can get inside you might find the module is a generic one like this. They are usually installed in the battery rather than the device to allow them to function in a charger.

I used to teach management, and large company figures are huge. To help students visualise billions I used to have a little quiz.

If you have £1Billion in cash and stick it under he bed. Starting on 1st January year zero, each morning you get out of bed, take £1000 from the pile and go out and spend it. When did/do you run out of money?

The answer surprises most people and helped students understand just how many £ there are in a billion.

Its about 6th November 2737 - so another 717 years and a few days to go!

Make a set?

Square Collets (homews.co.uk)

John, on the subject of rigidity of Taigs, you might like to look at

Lathe Rigidity (modelengines.info)

I have a Taig Micro lathe with the ER16 collet headstock. It is very small but works very well for small items. The ER collets handle material up to 10mm diameter. Anything bigger goes in the three or four jaw. See John Bentley's (http://modelengines.info) website for the sort of things it is capable of - in the right hands. However it doesn't really meet your requirements as it is only available in imperial. Fitting a metric DRO might solve that problem - it's on my (long) to do list.

Sherline do a very similar sized lathe that is available with metric leadscrews. It is also available with an ER16 headstock.

Pricing on both is likely to be lower than Cowells, and there are a host of add-ons and extras available to customise the machines to your needs.

Edited By Peter Cook 6 on 06/10/2020 12:36:37

I have followed this with interest. I have a couple of Eureka clocks which have electronic controllers. The controllers deliver a square wave signal at the frequency needed to keep the clock accurate (45 bpm). Because the period of the balance wheel varies a little with the amplitude (larger amplitude = longer period) the clock locks accurately to the electronic signal.

It's the non linearity of the relationship between amplitude and frequency that ensures the lock.

Thanks again for the information Jason - my wallet is tingling already!

Understood SillyOldDuffer, but pretty much everything I do at the moment can be classified as an experiment, so I am being a bit cautious not wanting bits of carbide insert (or anything else) flying around free.

Thanks again to you all for the patience you show.

A query to Jason.

A quick look suggests that CCGT tips are supposedly for Aluminium or non-ferrous metals while CCMT are for steel and ferrous metals.

What advantage would there be in cutting steel or cast iron with a CCGT Tip?

Thanks to everyone for their replies. Much helpful information to help a beginner up the (ever steeper) learning curve.

The toolpost is sitting down on the slide as flat (and tight) as I can get it. The gap is an optical illusion created by the chamfered edges of the toolpost. You can see the same illusion on the cut-off tool image on the website that Michael G references. As Jason says the tool is sitting on the flats on it's shank, and was set to centre height with the packing piece. I will file away Martin's suggestion of adding damping mass to the back end for future use.

I am not absolutely sure what the material is. It is a standard Seig SX1L bearing block bought from ARC (I am not yet brave enough to modify the ones that came on the mill without first getting spares!). It certainly cut like cast iron is reputed to. Lots of very fine black granular chips that made everything VERY dirty. When I initially opened out the holes on the mill I assumed it was steel and used a cutting oil - and that made a real mess. So I looked up cast iron machining (on here) and cut dry on the lathe; which worked well.

I chose the insert tooling because I could not get the lathe slow enough to use the correct speeds for HSS on cast iron. The tip is a CCMT - I will research the different tips - another task for the list . I have a project under way to replace the motor with a speed controlled DC one that will let me get down to 100 rpm or less. The problem () is that the lathe has now become the project rather than the enabler of the clock maintenance - the reason it was bought. The clocks languish unserviced!

The bearing modifications were a success, the mill is far smoother to use and with far less backlash (0.1mm on both axes - I haven't yet tried adjusting the split nuts). I was just fascinated by the regularity of the chatter. Thank you to SillyOldDuffer, that explanation seems a good match for the evidence. If I take the bearing blocks off again I will measure the chatter and see if I can get the same pattern on that software.

Thanks again to everyone for their time - one more inch up the cliff face of learning!

Edited By Peter Cook 6 on 24/09/2020 13:07:33

Edited By Peter Cook 6 on 24/09/2020 13:14:06

I was struggling with backlash on my new SXlLP mill, and much of it seemed to come from end play in the leadscrew bearings. Tighten them to eliminate play and they were hard to turn. Slack and there was too much backlash. So I followed advice elsewhere on the forum and fitted 16 x 8 x 5mm thrust bearings.

In doing so I needed to bore the bearing holders to 16mm. First experience of machining cast iron! I got (as I expected) some chatter but was fascinated by the regularity of the patterns produced.

The bearing block was held in the 4 jaw chuck (image 1) not balanced, so there as some vibration. However the pattern produced was very regular (image2), suggesting some sort of harmonic vibration at a higher frequency than the out of balance rotation.

Speed was 450rpm ( as slow as the lathe will go) with a carbide insert boring bar. The result was not a problem - the bearings are a great improvement - but I wonder if the experts can suggest the source off such an interesting vibration pattern.

I can't help with the core question. I have recently bought a Seig SX1LP from ARC. It meets my needs fine.

One thing I would say is to remember to budget for tooling, clamping, vices etc. I was warned to budget for at least as much again as the mill for a decent set of tooling and work holding. I can believe it from what I have spent so far!! When keeping your eye out, look for something that comes with a reasonable amount of tooling.

That curved top edge on the bridge is going to need some sort of rotating work holding (or a CNC setup - which is a whole different game!)

Thanks Clive - more additions to the list of projects!

Not sure I want to tackle that on my SX1LP !!

Just an update for anyone interested - against advice I ordered table & index plates from a remote supplier (China!) but who shipped from the Czech Republic so no customs or duty (until 1st Jan). Table arrived by courier in less than a week. First impressions good. certainly looks more than adequate for my needs and mill.

On investigation it turned out to be a 110mm diameter 4 slot 72:1 table rather than the 90:1 I thought I was getting. So opened discussions with supplier. Very responsive - offered a swap, or a discount if I kept it. Based on Jason B's comments about usability I decided on the latter.

Only downside so far is I need a 25 hole plate to do 25/50/100 divisions and that is not one of the supplied circles. So yet another project gets added to the (ever lengthening) list!

Much of the work on watchmakers lathes is done using gravers rather than saddles and cross slides and tool posts.

When using a graver and rest many right handed people find working left to right easier and more natural than right to left - watch woodturners shaping long items. How do you file a piece of metal right to left or left to right?

Hence the tradition - as Rod said - of watchmakers lathes with the headstock on the right. It is far more common on the continent than in the UK or US.

PS that is a very reasonable price for that setup with all the bits. Boley 8mm collets fetch £8-10 each and the faceplate will set you back the thick end of £120.

Edited By Peter Cook 6 on 12/08/2020 18:20:44

Thanks for all the advice - very helpful. The main projects I have on the (ever growing) list that need some sort of controlled rotation are a motor mount for the Taig lathe so that I can fit a DC speed controlled motor, and some calibrated dials (HH's Lining tool is on the timeline for that and the ratchet wheels will need the table). The motor mount needs curved adjustment slots but it will be in aluminium so less of a risk.

I have chosen to go with a 90:1 4 slot that comes with a set of index plates (for storage until the day comes - as it surely will). I was planning to get the Warco 110mm but it is currently out of stock. Axminster do the same thing but without the index plates but I found what looks to be the same deal as Warco elsewhere for a similar price.

Now to make an adapter to put the Taig chucks (M22 x 1.5 thread) onto the table. Why does every decision seem to add to the project list!

Thanks Paul for the warning. The reason I asked about relative strength was that the cheap 36:1 tables all seem to have the handle angles towards the centre while the 90:1 ones it is straight. That suggested the cheap tables had a smaller wormwheel, and I was wondering.

Thanks again for the advice

Edited By Peter Cook 6 on 12/08/2020 14:58:20

I am starting out with my recently acquired mill, and the (ever longer) list of projects contain several that would be easier (possible!) with a small rotary table.

The Mill (an SX1LP) seems to suit a 4" table. Reading the forum about such devices I think a simple H/V one would be fine. There seem to be two main choices (in my price bracket) 36:1 (10°/turn) ratio and 90:1 (4°/turn) ratio. The former are a bit cheaper, but the handwheel is on top in the vertical position while the 90:1 seem to have the handwheel horizontal in both orientations which would seem more useable on my small mill.

Thinking about the two raises a couple of questions.

Do the different ratios make one more or less useful ( both would be capable of being set to sufficient angular precision for anything I can visualise doing)?.

Which will be stronger? Does 90:1 mean more teeth (of the same size) on a bigger wormwheel, or many smaller teeth on the same size wheel. The former should mean the 90:1 will be be stronger (bigger radius hence lower forces for the same torque). The latter would seem to make the 90:1 weaker.

Comments gratefully received.