Tom Senior light X Axis power feed

I don't know how many members have the Tom Senior light vertical. I bought mine recently & seen that I am going nowhere soon

I thought I would do some modern sort of updates to it to come in line with these Chinese all singing ones. When I bought it someone had already fitted a 3 Axis DRO system to it of a very high quality. It is the M-DRO. Also it has a Toshiba VFD & 3 phase motor. Unfortunately the motor is only 1/2 hp. The VFD is a 1hp so maybe a motor change coming. I found it's short comings when drilling some holes the other day & it was easy to stall the motor at 50hz.

Anyway the plan is to fit a Tacho, ( on order if it comes). So I will have a clue to the speed. This will mean stripping the top plate off the motor housing to get access to the pulleys. The spindle pulley is where I need to make a ring in brass with a hole to accept the magnet. Reason being to keep the spindle in balance at high speed. Then the sensor will be vertical at the side of the draw bar. Any other idea's appreciated as looking at it , I can see no other area to fit one without it looking like a sow's ear.

The next project of which I have been on with for the last couple of days is to fit a X Axis drive motor. The kits I have seen advertised are around £250 & are not for the Tom Senior. So would need alteration to fit. So onto The Ford Mondeo wiper motor.

This was £8 on ebay & even came with all the mech, which was discarded. If you are like me then you spend more time looking at a job trying to work out the best way to do something, than actually doing it.

The left side end plate on the X is a cast item & only acts as a steady to the end of the leadscrew. It has no side inertia , but is the full width of the 1/2" shaft stick out. I removed this & remade A NEW ONE IN 3/8" Alloy, see pics.

I did a trial with the motor powered up & with all my effort to could not stall the motor. It has enough torque to do the job. I tried the rpm on both speeds. Came up with 40 & 52 rpm. I ordered & now received a 10amp 12v speed controller & a 20a 12v power supply. I have bought a new larger enclosure to fit this in.

Just drawing up a wiring diagram to give me control of the left & right travel , with speed control. A quick jog button for carriage return at high speed. Also a limit switch using the existing system on the carriage.

So far so good. However tonight I made a acetal guide to engage & disengage the drive. Totally boo boo'ed. It was 11.00 pm so decided to call it a night. I will make a new one tomorrow. Any feed back welcome, even to tell me I am daft even doing this. Just getting a sore wrist turning the Dive Dive wheel. The last picture is of making the bush fixing holes using the array command on the DRO, what a brilliant way to do drilling an array of holes with precision. The drill , I sharpened to mimic the taper on the wiper motor shaft, using an old drill bit. Just to add, so far it has cost around £60.

Steve.

Edited By Steviegtr on 25/03/2020 00:55:32

Hi Steviegtr,

If you have a look at my album, there are pictures on there of how I did mine using a salvaged wiper motor. I used a tumbler mechanism to provide forward, stop, and reverse feeds. I've not bothered with a clutch since the gears run so slowly that it is easy to change direction on the fly without stopping the motor. I also use a variable voltage DC power supply which allows me to monitor both voltage and current. A typical usage voltage for mine is around 5 volts and .75 to 1 amp depending upon load. I've had the motor voltage up to 30 volts for fast traverse without any issue. One tip is that these motors are designed to run in only one direction. Some have a thrust bearing at only one end of the shaft.

My comment is that if you want/need a mill with (seemingly) twice the power, then get a bigger miil.

Cleverer fellows than you designed this mill to use that 1/2HP sized drive. Doubling it should require more than simply changing the motor. I/m rather assuming, here that your aim is to install a 1HP motor? 3/4Hp is possibly too much.

Why a brass ring? Aluminium or steel would be cheaper.  Even plastic. Could drill identical holes at 180 degrees and fit one ‘dummy’ opposite the real one. Or what is the difference in density of the magnet and the pulley? Assuming here the pulley is not a pressed steel item.  Fitting two identical magnets, opposite to one another, would likely suffice.

Edited By not done it yet on 25/03/2020 08:59:36

Something mighty peculiar with that, unless you were doing something crazy - I assume not.

Either the VFD is current limiting, or the motor is still wired in star not delta, or perhaps both?  Any which way round, mine won't stall with the original 1/2 HP motor unless I go brutal, and we wouldn't want to do that would we?

HTH Simon 

Edited By Simon Williams 3 on 25/03/2020 10:14:36

A 1/2 hp drill with 80 to 3000 rpm can drill steel up to 20mm.

Your problem is not the rated power o/p of the motor.

That said the extreme taper on your drill might mimic the cutting load of a huge normal drill bit + the wedging action. You really should be boring that on the lathe.

Edited By Steviegtr on 25/03/2020 23:58:14

I did bore it in the lathe. But I do think the inverter needs checking. It is in delta & 240 windings. The motor is ancient. It says made in USSR. So how old is that. Yes it stalled way too easy. All stop on the project at the moment as my timber arrived today so I am busy making a partition in the garage to create a 4x3m workshop. Easier to keep warm. Plus keep debris away from my vehicles. Thinking about it. It is my fault as I altered some parameters on the VFD the other day & did notice the motor was hunting. It would not go past 52.5hz. I did sort that out but went into some deep settings. Luckily I wrote down everything I did , so will go back through them.

Steve.

Nice work. Totally different approach from the way I am doing it. Brings things into perspective about the way we all think differently. Looking at the way you have done it, I just hope mine works. At least if it does not I can put it all back to standard & put up with a achy wrist. Regards.

Steve.

The sensors are often pole specific so you could just set one magnet the wrong way round or a bit of scrap metal of the same weight as the magnet would do to keep balance.

Modern neodymium magnets are so powerful for their weight that you could probably use one small one, without noticeably disturbing the balance.

... and that’s quite an admission, coming from me

MichaelG.

.

Edit: These are amazing ... and smaller sizes are available

https://www.ebay.co.uk/itm/50pcs-N35-Strong-Round-Disc-Neodymium-Rod-Magnets-Fridge-Small-Craftings-/273945821655?hash=item3fc87181d7

Edit: sorry, I tried to link that, but ebay won’t play nicely ... so you will have to search.

Edited By Michael Gilligan on 26/03/2020 07:22:56

Hi Steviegtr,

A couple of notes that might help ! All the plastic gears were salvaged from a printer, a HP one if I recall, its been a couple of years since I built that one. The gear on the wiper motor shaft was just drilled through so it dropped about halfway down the taper, I used the nut to push it down the splines whilst using a "Cooks Torch" to heat the end of the shaft. Effectively moulding the gear to suit the taper and splines. Be careful here because some wiper motors have a plastic worm inside and you don't want to melt that. I also used a spot of oil on the taper to stop the plastic sticking to it.

The large white plastic block is a scrap of Nylon 60 20 mm thick used as the tumbler carrying the small gears, and is just pivoted on the end of leadscrew housing. Just a few screws and it all comes off ready for the handwheel to be put back on.

I'm happy to answer any questions you might have.

Best Regards.

Baron J.

When I fitted a VFD to my VMB I started assuming that I would also fit a tacho. However, with some simple figuring I can easily estimate the speed from the frequency reading on the inverter so I never bothered in the end and get on fine. Anyway the beauty of a VFD is you can vary the speed for sweetest cutting.

If I fitted 2 magnets I would get 2 pulses per revolution. I thought of brass as I have some. I was using the logic of just evening the weight & brass is heavy. Yes steel would do. Alloy is a no as would need counter weight.

steve.

I think you may find that hall effect devices may well be ‘polarity conscious’?

A circular disc will have the same weight for any similar segment. Any increase in mass is likely to have greater unbalancing effect unless mounted perfectly concentric.

The counter weight (for aluminium alloy) could be anything with the same centre of mass and weght of the magnet fitted diametrically opposite in a same sized hole as on the magnet side?

What you might use is arbitrary, but you have no need to stipulate brass as the medium. You only need to make a ring, not necessarily in brass - and even that may not be necessary.

Do take into account the metal, removed for the fixings, if you are really serious about balance. A small magnet with a central hole (for a screw) would suffice, I am sure - minimal increase in pulley mass - if the pulley is suitable (magnet could be mounted on the pullet boss, even, to reduce the effect of an angular momentum imbalance).

Have you checked that the windscreen motor is happy to run in either direction? Some, as I discovered to my cost, are designed to run in one direction only, and the brushes wear rapidly if run in reverse. A window winder motor is designed to run in either direction.

Steve,

Maybe daft, maybe innocent fun.

To be frank, if you worked for me you'd have had a couple of verbal warnings already. Now I'm going to have you in the office; You won't be offered coffee or asked to sit down.

Getting top marks for energy and enthusiasm won't save you. I will repeat earlier observations about slowing down and learning how to use machines before 'fixing' and 'improving' them. There will be a searching review of delivery so far, starting with the Myford. Suspecting you're a butterfly I shall want to see evidence that earlier projects have all been finished successfully. Pointed remarks will be made about over-confidence, shooting from the hip and the need for self discipline. Then a short, sharp lecture on why it is unwise for beginners to attempt advanced projects before they understand the basics. I might even unleash a cliche: 'Fools rush in where angels fear to tread'. I shall ask why you chose to ignore earlier advice. Lastly, and I suspect this will be the most painful part of the interview, I will ask you to explain and justify what yo are doing. What do you expect to achieve, and how do you justify this extremely haphazard approach? Is there a plan? Expect your reasons and logic to be challenged!

On the way out you will be handed a written warning. Next time you're sacked...

Back to the real world!

Of course, it's a hobby and we are free to do what we please. But if the interest is 'improving' (and why not), then I suggest Chinese machines are a much better target than decent British machines. Your Tom Senior is a well-balanced tool designed for precision rather than grunt work, hence it's smallish motor. Machine tools aren't like old cars of the same age. Cars often can be improved, but the Tom Senior design was good the day they made it.

Converting a Tom Senior is likely to spoil it and it's always sad when good tools are blighted by abuse or unwise modifications. Bad modifications will destroy the resale value. On the other hand, Chinese machines are made down to a cost, a bit rough, quickly assembled and set-up, and some components aren't top quality. They can be treated as a kit of parts and souped-up. No one cares if one is spoiled by unwise experiments. They're ideal for the guy who likes to uplift tools rather than make things.

Unless you're doing repetition work spending far more time thinking than doing is par for the course. My most important tool is an armchair!!!

Dave

SOD

Steve is Tim 'The Tool man' Taylor star of Tool Time in disguise.

Everyone knows a machine tool is improved with more power, preferably V8 and a dash of Nitro.

You wanna see my Barbecue.

Steve.

But only a fool would just drop in a big powerful engine without considering the strength of the gear box, drive train, suspension, brakes etc

The biggest issue with fitting a power feed to a mill you have hardly used is that it will give very little feedback. Until you have had time to use it and get to know what it is safely capable of it will be all too easy to set the feed far to aggressively and do damage, hopefully to just a cutter or the part but could also go further such as excess force on the feed nut or stalling the motor again and then what do you reach to stop first the motor so it does not overheat or the feed that is still forcing the work against a stationary tool.

I'd wait a while and decide if you even need power feed for the "small light parts" you said you wanted to make, I have a power feed on my mill but seldom use it, same goes for the tacho which I managed without for many years and probably now leave it switched off more than it is on. The sound of the machine and feedback through the handwheel tell me far more than a read out.

I dont know what size of magnets come with the tacho you ordered but I fitted one to my SX2P mill and one to my lathe.

The supplied magnets with mine are 10mm dia x 2mm thick and weigh next to nothing, so small and lightweight it didnt even enter my head the need for a counter balance and both machines run as smooth as I could wish for.

Thought all the Bessemer Converters had been retired m8