Member postings for MalcB

Hi Chris,

EN 24T and similars

Surface speed for HSS about 45ft/min.

Feed rates

Roughing for HSS about 0.005/0.006" per rev

Finishing for HSS about 0.002/0.004" per rev

At least 3 times or more faster for good quality inserts tooling.

Home workshop speeds here, not industrial

Edited By MalcB on 12/02/2017 20:23:49

I personally do not think its an ex Boxford factory fit for several reasons:

The dimple locations in place of more positive parallel pin locaters indicate to me it was intended for nothing more than angular marking out. A research establishment would not need to do this on a lathe. They would have much better equipment for this purpose. As others have said there is/are no other signs of provision for additional machining or work holding on the lathe to supplement anything else other than this.

It would more than likely be far more beneficial to somebody who did not have other means to provide indexing, does not have a milling machine and/or just has a good bench or pillar drill.

5 degree increments would be a good single incremental denominator for home workshop engineering, to supplement many subsequent drilling operations.

I do not think Boxford would clamp a locating block on the headstock directly on a painted surface, not good practise for any machine tool maker. I do think that Boxford if they had fitted the block, they would also have painted the block.

When this lathe was produced, good indexing equipent was very expensive and beyond the economical reach of many home engineers, especially in smaller proportions.

As others have mentioned, It was not uncommen for machine tool makers to supply a pot of paint with the lathe so could easily have been done by an owner.

For somebody building up their home workshop portfolio, lots of jobs like skimming the headstock, making the index plate, the location block etc could well have been done at their workplace as "foreigners".

My comments are in no way intended to be derogatory to the owner, in fact quite the contrary as for a Boxford AUD I think its actually right up there amongst the top ones i have ever seen, ( and owned ) especially in their original paint.

Having recently been on an invited factory tour of the Boxford factory I must say there is no resemblance to the historical pictures you see of their once main line production facility that was producing the machines that most people know them for.

I also respect the comments the OP posted about the Colchesters as I also had the round header Master and sorely missed it after I had my last Boxford AUD, such that I moved the Boxford on, in favour of a bigger machine.

Edited By MalcB on 12/02/2017 09:24:35

Yes, confirm my drawings showing same

Is this on the wrong thread J ?

Its highly unlikely they would sell the land because of future development opportunities, however they may be able to offer the option of a fixed period lease whilst they makes future decisions on it.

Hi Nick,

My wife bought me the materials/casting kit last year for my birthday at Doncaster show. Better deal than online. Various interupting projects since buying, including lathe change, plus now final fettling, polishing and painting stage of my Stuart beam means will be able to start it shortly, ( next couple of months if nothing interupts again ).

Away from home until late Thursday but if you have not resolved by then i will check out the ( comprehensive ) manual you get with it and post details.

Malc

👍👍👍

The use of buttons goes back well before my time and its about 40yrs since I last used mine in industry. Mine were made in the toolroom amd were hardened and ground.

There were commercially available ones and which had one button longer than the others. I think the practise at the time was more or less to copy commercial ones.

The longer button was occasionally used when a particular hole was needed to form a datum position and identify it accordingly.

I do strongly suspect however, that this may well not be their intended purpose, as I said they go back in history some time. Perhaps others may know.

Edited By MalcB on 06/02/2017 16:24:35

My two sets of toolmaker buttons:

We used toolmakers buttons in the toolroom/toolroom inspection as follows:

Toolmakers making complex drilling jigs would mark out hole positions for the drill bushes using height gauges and the like in relation to the component to be drilled location surfaces and pads etc.

Toolmaker would drill and tap through each hole about 2-4BA etc where the drill bushes were to be positioned. Buttons would then be secured to each tapped hole ( plenty of clearance twixt buttons and fixing screws ).

Jig would be sent into tool inspection area/department.

Jig would then be very accurately set up by a tool inpector and all the buttons Precisely positioned accordingly.

Set up datums would be identified for the jig body.

Jig then moved on to jig borer.

Jig borer setting up to inspector identified datums.

Jig borer would usually set up true to each individual button one at a time.

Jig borer would then slot drill and then with boring bar finish to to suit outside diameter of slip bush for drill bushes.

Back into tool inspection for final checks.

By complex jigs, I refer to those where the jig borer found it difficult or impossible to get at the components location faces and pads etc directly.

Edited By MalcB on 05/02/2017 20:06:51

Out of interest:

Has any body stripped any of the 3 phase bench grinders to see if their motors have the option of being wired for Delta?

Malc

Very interesting article, more to take in on the VFD learning curve.

A lot of info in there is covered in some of the manufacturers installation manuals, but there are quite a few manuals I have read that dont touch on a lot of its contents.

It would be interesting to see how many home installations have every power cable and every logic control cable running is steel tubing and how many are seperated by 12".

Thanks for the link John.

I cant believe Warco would do such a thing if they in fact fitted the readout themselves, the mind boggles.

Its certainly not what I think can be perceived as good engineering practise.

The scales are supposed to be held in correct alignment within a couple of thou.

They must not be bothered by the fact that at some time in the future the owner will need to replace them and try and get the scale back aligned, but heyho, its going to be out of warranty by then.

Stuart, I find it hard to believe somebody actually fitted a DRO scale directly on top of the rubber. Personally if it was my machine, i would remove and re-fit the scale and reader assembly just for piece of mind. At a minimum i would remove its cover and clock up the scale to check it out before any real damage could happen.

Clive,

Thanks for input and yes I will keep you all in the frame with results when I finalise settings.

Hi John,

Reading your question in conjunction with Clive response as well.

I have two Teco inverters that i have installed. Both models have a variable frequency potentiometer on the face of the inverter, like on the more expensive Inverteks.

I have a 2.2kw Teco EV series on my Harrison M300. Its a late machine (2003) which has  more contactors and overload protectors than the earlier models. MEW 145 covered a conversion for mine. The logic control to the inverter in this article seemed overly complex so i did my own circuit diagram, got my electrical wizard friend check it, went ahead and rewired it all to utilise all the machine controls and interlocks, not really wanting to do any with the inverter, which i left set at 50Hz max. I can still use the pot on the front to vary speed if needed, but the M300 has such a good speed range i think it will never be necessary.

The Teco I have just installed on the VMC. is the L510 series 1.5kw model, which is to be used opposite to above in that i am using frequency range to change speeds.

I do not understand what you would gain by having switched frequency ranges. If you programme the inverter  to use the potentiometer with a speed range from say 0 to 100Hz why would there be a benefit switching in between? I cannot see in the manual that you can use different ranges, only a min and max, but does not mean i have not missed it.

 Its as Clive has established, setting a wide frequency range and then setting the belt position to achieve the optimum compromise of max speed, lowest speed, satisfactory motor cooling at lower frequency and minimum amount of belt changes if needed.

If its an issue of knowing exactly what speed you are doing and your inverter does not have the ability to display revs then its still really simple.

Once you are satisfied with the fixed initial belt position,  buy yourself a digital tachometer like I just have.

You can get a decent one for not a lot of money. Use the tacho and at each of the potentiometers markings, take a reading and the do yourself a chart of frequncy setting vs RPM, which is what I would have done had I not got the parameters to do this on the Teco.

To generalise a little.

One of the big learning curves for me is using inverters and I have a lot to learn yet. When I first started looking at and learning about them, I download quite a few manuals ( and i mean quite a few ). I found some very easy to tead and follow right thru' to those that were megga difficult to understand. Loads of Youtube videos watched, each time gleebing a little more understanding.

I actually found the Invertek and Teco not to difficult to follow and these were makes high on consideration list.

Edited By MalcB on 01/02/2017 09:20:07

John,

Yes it does and the thermister block is there in the terminal box as well. It has ability to display the temperature but I am not sure if is able to do any further controlling. Its unlikely I will use it, but I will research it further out of pure interest and learning.

Clive,

Very interesting, If I opt for the lower 1380RPM setting at 50Hz the top speed hits about 2100 RPM at 75Hz or 2200 if i squeeze it a bit. May be better running with this option with a belt change for higher speeds than 2100/2200. Will give it a few weeks and swap over. I do use wigglers and edge finders.

Edited By MalcB on 31/01/2017 21:54:19

Well tachometer arrived today and was able to see exactly where i was up to with actual spindle speeds.

From trials I am playing with two options to set belt speed at for 50Hz.

Have option of 1380RPM or 1800RPM.

For the time being I am going to run with 1800RPM setting at 50Hz.

On my Teco going into parameters Group 12 have set parameter 12-03 to show 1800 RPM at 50Hz. Have set parameter 12-04 to read display in RPM ( up to 5 fig integra ).

Display now shows spindle speed as you go. Spindle speed at 75Hz ( Tec's max rated speed ) is 2700RPM or a tad more if I wanted to push it. Will see how we go and monitor motor temp any periods on lower speeds. May fit digital thermo on it.

Edited By MalcB on 31/01/2017 19:12:36

I bought a set of raw castings and materials off Gumtree for the std Stuart Beam Engine a couple of years ago which hadnt been started and that were originally purchased from Stuart over 30 years ago.

The piston material suplied is gunmetal in my kit. Dont know whats in their current kit. Their drawings then did not spec the material for each item. Dont know if their current drawings do?