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Member postings for Avon

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

Thread: How to strip a Centec 2A Vertical Milling Head
27/07/2020 22:35:19

Hi Duncan,

I counted 28 on the driving shaft and 32 on the driven. By my calcs that gives approx 15% reduction in speed of 1600 input shaft and 1400 at the quill. Photos below:

Hope that helps.

photo 27-07-2020, 22 04 07.jpg

photo 27-07-2020, 22 07 09.jpg

photo 27-07-2020, 22 03 33.jpg

Edited By Avon on 27/07/2020 22:38:24

Thread: centec 2a halfnuts
19/07/2020 20:17:26

Hi David,

Address received - will post next week.

Yes I do have the handbook - not really sure where I got it actually, its in PDF - did you send it a while ago?? (i'm getting increasingly forgetful!!).

I found a centec router on ebay, which looks like it might fit - and I think I have some of the other items that are with it - I'll have to have another look in Dad's workshop as it may still be there since I wouldn't have known what I was looking for!

All the best.

Peter

17/07/2020 09:17:44

Hi David,

Can you message me with your address and I'll get it sent back - absolutely not a problem, I'd rather it was in a good home and I know what you mean about searching for things you no longer have!!

Hi Dave Halford - I've never been aware of a slotting machine, though the name obviously gives away the intent. I guess its an adaptor intent on languishing in a box until its use is obvious!!

Hi 'not done it yet' - looking at the half nut supplied by David I suspect that my father was trying to make a halfnut and then decided that a full nut was easier, I can even see where he filled in the slot.

Regards

16/07/2020 12:07:28

Hi David,

Amazing response - really appreciated as parcel arrived this morning. But sadly it’s the smaller size as mentioned elsewhere. I can either return it or hold it in case someone else has a need.

I guess we should have checked. Such is life.

Let me know what you’d like me to do.

All the best.

Peter

15/07/2020 18:17:17

Hi Duncan,

Email sent with both DXF and DWG. For info the link to the ONSHAPE drawing is:

https://cad.onshape.com/documents/a2e0a0ebaf385baddcff3f15/w/d4fa5ebbd6215d9ab93d4805/e/cf7ccd99fd7d2bb21ba9292c

I use 1/128" as that's what my calipers give me - I'm measuring as built/worn out so its almost never a nice number, though on occasion I have thought that my lathe in particular is more metric than imperial!

For info, do you have any idea what dirty green accessory might really be for in my picture above? Its a perfect fit to replace the Quill Head on the Mk3 vertical unit, but I found nothing in my fathers workshop to fit it - my suspicion is it should be a grinder attachment, but thats a guess.

Any ideas?

All the best.

14/07/2020 14:19:40

Full NutHi Duncan,

Hope these help. If you want more from the drawing I can share using Onshape (my goto CAD package)..

Regards

full nut drawing

14/07/2020 11:31:39

Hi Duncan,

I removed the table before I even discovered the nut - its about 30years since I've seen this mill working so have been stripping it blind!. I'll do a drawing and photo of mine and post here - it might be more helpful.

Shouldn't take too long.

Regards

14/07/2020 11:07:55

Dave, not done it yet,

At this stage I've not even started to think precisely what I'll use it for, and certainly won't be commercial. But since I'm spending the time refurbishing it I thought I'd like to restore it to as near original as I can.

I suspect that like Dave, I'll not be bother to do it too often, unless I can use the quick feed to actually make a cut on each pass. It did occur to me that since I have an adaptor (see photo) for the Mk3 Vertical Head that looks like it should hold a grinder perhaps I would use the quick feed in that circumstance.

Regards

vertical mill accessory.jpg

12/07/2020 23:29:29

Mine is the underdrive version and just checked that the leadscrew (is that the right term for a Milling Machine?) is 5/8".

Mine has a full nut which obviously can't be disengaged - I assume my father fitted it, but really not sure. Neither am I sure whether I need to fit a Half Nut - it seems correct to do so as that was how it was designed, but a number of posts suggest the quick traverse facility isn't really needed?

12/07/2020 19:33:26

Hi DAG, I know this thread is quite old, but wonder whether that half but is still available (for a reasonable consideration 😊 I have a 2A which has a solid nut fitted and I’d like to get it back to the original state?

All the best.

Peter

Thread: How to secure a Piston Rod in the Piston
13/06/2020 17:20:04

Excellent, many thanks for the prompt replies - now off to source some material and learn how to sharpen my tools properly!!

I had used the talistock to support the die, so reasonably confident the error was in not being so careful when tapping the original piston.

I'm learning!!

13/06/2020 16:11:40

well that wasn't a success. Lesson to self: 'be more careful when tapping a hole to make sure that the tap is square to the job'! I have a beautifully fitted piston rod with a piston that now wobbles!

So it looks like I shall be taking Redsetter's advice and making a new piston. Therefore, a question: What material should I make it out of? The original is clearly steel, but I don't know what grade - does it matter?:

12/06/2020 20:40:46

HI Guys,

I had to use a punch to drive the rod out of the piston. In truth I was surprised that there are two different diameters in the piston and it was that that led me to believe that it had been riveted (ie the end hammered to widen it out to fill the gap).

I think the idea of tapping it is probably the best. I can probably reuse the original piston as well. There's nothing wrong with it fundamentally and my slowly developing lathe skills are probably not yet at that level - that said I could give it a go just as a training exercise!

I'll let you know how I get on.

12/06/2020 17:42:41

I know this should be simple, but I don't know the answer.

The piston rod in the attached photo has sheared at the pin where it is articulated. How to solve that is tomorrow's problem.

Having extracted the pin from the piston I realise that the 3/16" piston rod has been reduced to 1/8" to fit through the hole in the piston. The hole in the other side of the piston is 5/32" so I've assumed that I now need to hammer the piston rod to expand it, rivet like, to secure it in the piston.

What I don't know is how best to secure the piston rod while I hammer it - I don't want to spoil the surface of the piston rod as it needs to be a good fit through the gland housing. Additionally, I don't think I should be trimming the rod to size at this stage as the hammering is then as likely to flare the bottom end as well as the top.

I've also included a drawing of the two parts.

PS. Does anyone know the maker of this model? It has a W on the valve cover.

Grateful for any advice.

photo 12-06-2020, 10 49 26.jpgpiston rod drawing.jpg

Thread: How to strip a Centec 2A Vertical Milling Head
05/06/2020 18:21:29

Finally produced a new drawbar. Turns out the thread on the original was 5/16 BSF (22tpi). So I've turned down a length of 3/8 and threaded it. I've added a length of Hex bar to the top with a 3/8BSF (20tpi) and will also drill and pin it when I can. The 3/8 rod is a firm fit in the quill, but I can turn it fairly easily with fingers so don't think it will cause any problems and should transmit any stout taps without too much flexing.

Its not at all sophisticated, but I think it will suffice and if I need to make another at least I now know how.

Many thanks for all your help and ideas.photo 05-06-2020, 17 08 50.jpg

20/05/2020 15:53:29

Gentlemen,

Firstly, many thanks for all your efforts, information and advice. It has all been useful and the photos of the drawbar arrangement will inform my manufacture of a replacement.

Below is a photo of the thing apart.

In the end I took it to an agricultural repair shop as the chap is frequently called on to renovate/repair machinery that has been hard used and unloved. It transpired that the ring/snugging nut was almost certainly in contact with the rear face of the chuck, so I was unable to gain further clearance between it and the end of the spindle which I is what I'd tried to achieve in the earlier photos. So we turned in as shown in Peak4's photo until it bore against the bottom of the spindle - it took a considerable effort to move the nut and a man sized spanner stopping the spindle moving which was clamped in jaws of a large Colchester lathe. We then tried heating it, but it made no difference. So back in the lathe and with some more enthusiastic hammering on the spanner until it finally came apart.

The snugging nut is a nice clean thread so I'm sure it was just very tight up on the body of the chuck. The drawbar takes a meandering path from one end to the other, no wonder it wasn't very useful. The taper on the chuck seems to be nice and clean, but that in the quill has clearly had swarf and other inappropriate things in it. I'll have to get an MT2 taper reamer to clean it up.

Gents, again thank your for you help - it gave me confidence in what we were doing and a successful outcome.apart.jpg

PS. Why is it so difficult to work out a lefthand thread when we understand a righthand without thought!

20/05/2020 15:53:28

Gentlemen,

Firstly, many thanks for all your efforts, information and advice. It has all been useful and the photos of the drawbar arrangement will inform my manufacture of a replacement.

Below is a photo of the thing apart.

In the end I took it to an agricultural repair shop as the chap is frequently called on to renovate/repair machinery that has been hard used and unloved. It transpired that the ring/snugging nut was almost certainly in contact with the rear face of the chuck, so I was unable to gain further clearance between it and the end of the spindle which I is what I'd tried to achieve in the earlier photos. So we turned in as shown in Peak4's photo until it bore against the bottom of the spindle - it took a considerable effort to move the nut and a man sized spanner stopping the spindle moving which was clamped in jaws of a large Colchester lathe. We then tried heating it, but it made no difference. So back in the lathe and with some more enthusiastic hammering on the spanner until it finally came apart.

The snugging nut is a nice clean thread so I'm sure it was just very tight up on the body of the chuck. The drawbar takes a meandering path from one end to the other, no wonder it wasn't very useful. The taper on the chuck seems to be nice and clean, but that in the quill has clearly had swarf and other inappropriate things in it. I'll have to get an MT2 taper reamer to clean it up.

Gents, again thank your for you help - it gave me confidence in what we were doing and a successful outcome.apart.jpg

PS. Why is it so difficult to work out a lefthand thread when we understand a righthand without thought!

19/05/2020 17:37:10

Hi Dave, All, I think its well and truly set!

I've heated it (wife didn't notice it in the oven - only 120C) then cooled the chuck in cold water. Clamped it in the vice as show and gave the well fitted spanner some enthusiastic attention. Not the slightest sign of if moving and I checked and thought through multiple times whether I was trying to turn it in the right direction - I'm certain I am!

The spanner is now showing signs of cracking (maybe a bit too much enthusiasm) and tomorrow we're off to a local engineering firm that are experienced in attending to old agricultural machinery and the chap is a bit of a whizz (I'm told and hope).

Maybe that's why my father never seemed to us it very much - I know I can use it setup as it is, but it'd be a shame to refurb the rest of the machine and not get this sorted out.

I'll update the thread when I've made some progress.

in the vice.jpg

Edited By Avon on 19/05/2020 17:37:32

Edited By Avon on 19/05/2020 17:38:16

18/05/2020 19:55:45

Dear All,

The quill is out of the bearings so I've found the taper rollers and oil seal mentioned by Duncan. I think I'm going to try using a bearing puller first (I think I have one somewhere), perhaps supported followed by making up some wedges as mentioned by 'not done it yet'..After that some heat, WD40 and possible a good whack with a mallet - Old Mart doesn't believe that the drawbar would be captive - so an enthusiasic whack might be all thats required.

I'll let you know how I get on!!

Many thanks

18/05/2020 16:47:39

Hi Howard, I've been thinking about the careful use of heat to free things up. My first concern though is the drawbar which I presume will prevent any effective use of wedges - unless I've completely misunderstood the drawbar's function (entirely possible).

To heat it up I was actually thinking of putting it in a bath of boiling water? It'll be hot, but can't get too hot.

Peter

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