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Member postings for Tony Ray

Here is a list of all the postings Tony Ray has made in our forums. Click on a thread name to jump to the thread.

Thread: VFD help required
14/05/2021 22:17:54

To get the best out of the VFD conversation you should rewire the controls to make use of its control circuitry. I did this on my M250. There was an article in MEW on an M300 conversion a few years ago. Can recommend Schneider Altivar VFDs.

Thread: Milling machines - western-made s/h recommendations up to 2k
04/04/2021 08:59:19

If you are going to use the shed then imho a concrete floor with a damp proof membrane is a must. I would however seriously consider the nuclear option if you think you are going to outgrow the shed as extending a slab is more work than pouring a new one. My friend built his 5 x5M wooden workshop 25yrs ago and apart from renewing the paint it has had no more maintenance that my blockwork one. I built the daughter aplay shed using the same principles which my missus has been using as a home office since the first lockdown it’s a great space. The construction techniques are simple and the materials readily available. I would recommend the use of bitumen roof shingle over felt every time.

Thread: Boxford STS Screwcutting Clutch
04/04/2021 08:01:04

Hi Don,

Please post some images of your lathe’s gear train and if you have any details of the clutch implementation on the similar lathes you mention those too so we can see where you are struggling.

In case you need it: To post images you need to create an album to which you can upload them, from there you can then select them when you are writing you forum post.

Tony

Thread: KERRY TYPE A.G. LATHE
18/03/2021 07:56:41

Just to clarify you gears do not need to be ‘accurate’ i.e. precision ground to fine tolerances, all they need to is be able to run together. By that I mean all gears in the set must be able to be meshed with each other with no binding and not too much backlash. The purpose of the gear is simply to transfer motion from one to another at the desired ratio and be strong enough to transfer the power. In a 15 T to 30T gear train the ratio is the same whether the gears are precision ground or 3D printed. When cutting a thread that is not a multiple of the lead screw the closeness of the gear ratio to what is theoretically required is a factor. The pitch accuracy of the screw being cut is determined by the lead screw accuracy and the size of the error in the gear train ratio. Backlash in the gear train and lead screw is inevitable but the screw cutting process allows for it; the cut is always taken in the same direction and the tool is always started a few threads distance beyond the work so that the backlash is taken up before the tool contacts the work.

Yes bed levelling is important. Chep on the ‘tube has som excellent advice on this, another tip I used to take up a dip in my bed was to shim it with post it notes between the bed and the removable magnetic build plate. I also took some time to calibrate the extruder and I can get to about 0.2mm on finished parts.The 6 spline on the Harrison gears is finicky and I had to adjust the model until I got a good fit, now I have this sorted it’s just a case of dropping this element into each gear model. In your case a bore with a single key way can be achieved in many ways. It will be worth increasing the fill density around the bore and the teeth. If you need further help on this please ask.

I highly recommend Ivan Law and Martin Cleve’s books on gear and screw cutting respectively.

17/03/2021 21:31:39

Hi,

I don’t think you don’t need to spend that amount of money on change wheels

**LINK**

I’m sure this seller can make you what you need. Alternatively If you have access to a 3D printer you can print them, I have been experimenting in making them in 1.5 mod with the 6 spline centre as per the eBay listing, you may need to fettle the key way with a needle file. Many lathes use plastic/ tufnol gears.

Tony

Thread: EXE Surface Grinder Manual
10/03/2021 07:06:55

Have a look at the Exe, pages on Lathes.co.uk the ris mention of someone called Oliver Slocombe who has some parts for sale he may be able to help you or direct you to someone who can.

Wel done on the acquisition it is very nice machine.

Thread: Boxford STS Screwcutting Clutch
09/03/2021 18:44:53

Hi Gray, I will keep the alternative banjo idea in mind but I’m going to try to develop the second shaft arrangement. Your comment re keeping the new output shaft on the same circle in relation to the input shaft he to screw cutting box was very helpful. I lie the idea of using an HTD belt to transfer motion to the new shaft but the shortest length seems to be 300mm so it might need a jockey wheel to fold it into the space required.

I think relocating the banjo is not going to be an issue and one I can manage.

Thanks for future explaining the your Emco version, what is the piurpose of the other gears that are in it ?

Regards

Tony

09/03/2021 18:32:04

Hi Clive, as you say you don’t have a lot of room to work with. The operation of you coaxial clutch is straightforward and I’m assuming that that’s a schematic as there looks like a lot of opportunities to make it more compact. Unlike you I need to change form metric to imperial quite regularly as I only have one machine. I would imagine you have the P&W for imperial and the S&B for metric?

08/03/2021 23:51:03

Clive: I’m glad I was of help in a “But I didn’t do anything” kind of way.

Thanks Gray & Clive for confirming my understanding of the STS solution, it is not yet my solution for the Harrison, and finally thanks also Gray for ansewingbwhat was going to be my next question regarding the use of the lathes existing fwd / rev knob.

08/03/2021 07:49:48

Ok I think I have the STS solution figured out, I had a light bulb moment last night so here goes:

A 30T gear fitted with a drive dog is fixed to the output shaft from the lathe . Engaged with this gear is a 15T idler that is wider so that it engages with a second 15T idler which then drives a second 30T gear also fitted with a drive dog that is free to rotate on the final output shaft. The two dog gears face each other and interposed is a clutch plate that is slid either to the left or to the right to engage with either drive dog. The clutch plate is keyed to the final output shaft. When slid to the right the clutch plate and therefore the final output shaft is driven in the same direction of rotation as the lathe output shaft. When slid to the left it rotates in the opposite direction because the second dog gear is driven off the first dog gear via two idlers which reverse the rotation. Because the idlers have the same 15T tooth count and both dog gears 30T the final output shaf rotates athletic same speed as the lathe output shaft no matter which way the clutch is driven. Finally for the sak of completeness the clutch is actuated with manual via the knobbed lever that project towards the from of the lathe or by the trip mechanism which runs down to the trip bar.

I think that it, this will help me figure out what my solution.

08/03/2021 07:18:17

Thanks for the detailed explanation of the P&W which I don’t fully understand but I ‘m sure will prove useful to others and maybe myself in developing an M250 solution.

06/03/2021 11:59:09

Some great ideas here, not being blessed with a mechanically minded brain I have a question about the P&W clutch Clive: Am I correct in thinking that the output shaft direction of rotation is handled by another means not shown in the diagram? I like the idea of electromechanical actuation, that could solve the issues around sensitivity that Trevor is working on, I would think that suitable micro switches on a stop bar with an E stop as a fail safe would work. Your idea Clive of a DRO output stop signal is a good one and would not I think be difficult for someone with the right skill set but perhaps a full implementation of Clough42’s electronic leadscrew would be another solution.

Trevor has kindly sent me the cad files and introduced me to Nanocad so I can view them - many thanks Trevor.

Anyway off to the Workshop to get a better idea of what I have to work with.

Thread: Steadies
05/03/2021 18:55:56

I think it depends on what you are doing. Good point re preventing swarf getting in, I have seen a people make up a polythene shield basically with a hole in the middle to suit the dia being turned, care obviously needs to be taken to avoid it becoming entangled in the work.

Thread: Boxford STS Screwcutting Clutch
05/03/2021 18:48:29

Just noticed that I failed to swap the compound gears for the 44T set up.

05/03/2021 18:46:30

I don’t think I would want to attempt an internal mod without a spare box to work on so here is a preliminary look at moving the banjo. The boss supporting the input shaft to the gearbox is cylindrical but smaller in dia that the current banjo and has protruding cap heads but they can be changed. A sleeve could be made to make up the difference. I hung the banjo on the boss with the two sets used to cut metric pitches.

22T on the output

img_1786.jpg

44T on the output, the compound gear are just swapped round between the two setups. The wire is just to hold it in position

img_1789.jpg

so my initial conclusion is that this could work , the banjo is not a complicated part to make and I can 3 d print mock-ups. I think I need to make an accurate model in Fusion360 then model the various gear trains needed to cut imperial, module and DP. I am fortunate to all have a full set of change wheels to do Imperial threads although recent experiments have yielded useable 3D printed items. Moving the banjo then gives a large space in which to implement the dog clutch. That will of course need to be figured out but it should be possible to use Trevors excellent solution as a starting point.

05/03/2021 18:20:38

Its going to take me a while to process all of that useful info, I spent a bit of time this afternoon looking at the possibilities. This is the banjo in its upper most position, this reduces the space envelope to approx 40 x 90mm. I think I will need a more detailed explanation a new a sketch to understand Gray’s suggestion.

img_1780.jpg

Thread: WHERE ARE THE SHAPER USERS ?
05/03/2021 07:37:57

I’m not shaping yet but here’s a pic of my Alba 1A to Elliot 10M poly vee conversion. sorry it’s inverted.

12214a09-e55e-47b8-a77e-7fe62afa7327.jpeg

Thread: Boxford STS Screwcutting Clutch
05/03/2021 07:24:49

I can’t immediately see how the Boxford solution is going to be work with the banjo in its current location.

m250 annotated.jpg


The driving gear sits on the shaft on a splined adaptor ( shear pinned to the shaft) that has been removed for clarity. All dimensions are approximate. Two possible routes come to mind, develop something that sits outboard of the driven gear or look at a new banjo arrangement pivoting on the lower input shaft to the feed and screw cutting gearbox. It looks like the oil filler elbow would have to be replaced, that wouldn’be a bad thing as it looks like it came out of a plumbers merchants! Sorry for the poor image the machine is right up against something els so I just have room to remove the cover & do change wheel adjustments.

04/03/2021 21:43:54

Hi Trevor & Graham,

Thanks for your replies. Firstly I can confirm that the output shaft on the M250 rotates exactly at the same rate as the spindle. Looking at the output shaft side on there is a boss approx 10mm deep that is bolted to the main casting, This supports a 38mm spigot on which the banjo hangs. All in all there is 40mm between the back face of the driven gear and the main casting which is a flat face. This space is occupied by the 10mm thick boss 14mm thick banjo and various spacers.

**LINK**

There is a good image of the drive set up on Lathes.co.uk

I will try to post some images in a few days.

04/03/2021 08:02:35

Hi Graham’s & Trevor,

As previous poster commented the STS solution may well be a good start for other machines which have the tumbler reverse in the headstock. I have a Harrison M250. At first glance it looks like the challenge on the STS I was to get the unit in the space between the headstock casting and the first gear in the external train so as to maintain the alignment of this gear with the next one located on the banjo. On the M250 that first gear is commonly changed to obtain two ranges for screw cutting in my case 22 & 44T being metric. I must admit even with Grays book I struggled a bit to understand where this all fits until I read Clive’s helpful explanation which is worth repeating here:

“Screwcutting clutches are single tooth dog clutches running at spindle speed, located before the screwcutting drive gear train, operated by a fast operating knock out trip”

I will contact Trevor to ask for the CAD files as Inthinknthey will be a good starting point for the M250.

Tony

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