Centec question

[Garry BellParticipant @garrybell53110]

New member

[Garry BellParticipant @garrybell53110]

Hi all,I am new to the Model Engineers Forum, my name is Garry, I spent a little time in engineering,many moons ago, over the many following years I have often missed the ability to make, repair, manufacture from mind to metal, so much so.that I have recently purchased a Centec 2A with a mk3 head and I have just finished machining a riser block for the said machine, its not been fitted yet as I am awaiting a new drive belt some 240mm longer than the one in situ.
My question is, as a new owner of, what I can only say is a really nice machine is: Does anyone here have a Centec Mk3 head? And if so could I ask as to how the drawbar is removed? I would like make a new one? Well I dont know the condition of drawbar thread as they tend to get a bashing to break the morse lock.
I have also bought a Myford ML7.
Thaks in advance, Garry

[Ian McVickersParticipant @ianmcvickers56553]

My first mill was a centec with the MK3 head and I made a new drawbar for that as well. I'm pretty sure it just lifted straight out. Try some gentle persuasion.

[Brian HParticipant @brianh50089]

Welcome Garry, do you know of this site for machines and manuals? And it's not just Lathes.

**LINK**

Brian

[RMAParticipant @rma]

Hi Gary. Yes I have the same machine and head. From memory I think it just lifts out, haven't had to remove it for year's. Always wanted a raising block, but never got round to it.

[duncan webster 1Participant @duncanwebster1]

Mine's a 2B but it has the same vertical head. It doesn't just lift out because it is a self eject drawbar, turn it anticlockwise and it pushes the taper out, provided you haven't over-tightened it. I can't remember how it comes out either, and the manual I've got doesn't cover the vertical head. If you take off the conical thing at the top it exposes the spring which holds the quill up against gravity, after that you'l have to pay it by ear, but it can't be hard, I've had mine out.

Assuming you have the 2MT version, It would be very useful to be able to have a 10mm drawbar as there is a lot more tooling available, but previous posts on here suggest you can't get 10mm down the hole. Whilst you have it apart I'd check.

The answer to your next question (what oil to use) is I think ISO 100 hydraulic oil, but someone might know better. And yes they all leak a bit down the quill as there is no rubber seal, just a very good fit.

[RMAParticipant @rma]

Agreed, once you take off the top hat you can see what's involved, very easy really but as I say, I haven't had to dismantle mine for ages.

[peak4Participant @peak4]

Garry, the quote from the manual is

The draw-bar does:not come away from the head in normal use but it can be removed
by unscrewing the lock nut (33) an anti-clockwise direction,

If you send me a message with your email, I'll let you have a copy

Bill

[peak4Participant @peak4]

Not quick enough to edit my posts; See HERE for a link to a download

Hello and welcome by the way.

Bill

[Gary WoodingParticipant @garywooding25363]

Interesting. I too have a Centec 2B with a MK3 VH, but it uses INT3 sockets, so no need to push things out. A light tap is all that's needed. The draw-bar just lifts out.

I've made about 20 raising blocks but it takes a lot of work and there's no way I'm doing it again. The photos show some long blocks and a short one. The VH can be left on the long block 'cos it can be slid forwards to act like the over-arm for horizontal milling.

 

Edited By Gary Wooding on 28/01/2019 08:22:13

[Garry BellParticipant @garrybell53110]

Wow, what a response, thanks lads,I’ve downloaded the details for the machine ( thanks Bill) and the link to the lathe.com website has been a constant companion over the past few months for me and helped me choose the Centec as a machine to have , but thank you anyway Brian its good to know you guys are there to help.
Armed with the forum info I popped off the top hat which is not original by the way, it is a half st steel flask welded very neatly to a flange with the cup lid a screw on cover, someone must have misplaced or damaged the original.
My drawbar is 3/8 BSW at the end it looks like a length of screwed rod that has been releived of the top of its thread to .336(8.53) Dia along its length
I thought it looked a bit iffy when I saw two nuts locked together at the top.
This drawbar came out of the bottom when I removed the nuts, I imagine it may have been 5/16BSW in original form, to fit from the top(thats why I had to give the bar a light tap with a piece of brass I have to release the morse lock.so a replacement like for like will retain my 3/8 BSW tooling and a Drawbar with a 10mm thread could bring me in line with current more abundant tooling.
I have recently made a morse adaptor for a the dovetail cutter I used for the riser block( no space for the material and a collet chuck) the riser is made from 120x80x225 cast iron bar.
Anyway I am rambling!
Thank you all for your responses
Take care.

[Garry BellParticipant @garrybell53110]

Gary they look supurb!
I have a length of 80x80x450 long to make a long overarm
Your not kidding about the amount of work, a 120x80x225 block of cast is right on the limits of a 2A’s machining envelope. 2 setups for the clamp pockets at 30degrees to virtical and holding the thing down and clocking was a faff but on saying that I enjoy the challange.

Thanks for the post, do you have any long risers without a home?

Edited By Garry Bell on 28/01/2019 19:13:22

[peak4Participant @peak4]

Garry, this is what the drawbar should look like; well almost, mine's been stretched at the thread end by one of the students under previous ownership.
The peg spanner is a normal adjustable angle grinder one.

I could do with making a metric one as well, but it's a bit of a faff to keep changing it.

Part Assembled;

Fully assembled;

and with the safety cap, it's actually more the shape of a disposable coffee cup than it appears here.
Only realised when I came in and it's too cold to venture out there again.

My other mill is a Dore Westbury, which will only accommodate a 6mm or 1/4" drawbar, hence all my MT2 tooling has a removable slug which is tapped M6 and externally threaded M10 or 3/8"

I was thinking of making a new drawbar for the Centec, but tapped M6 at the end, rather than threaded 3/8" BSW external.

I could then use a length of M6 high tensile chopped off an allen bolt and loctited in place to give a strong thread at the end.
Since my MT2 tooling has M6 slugs in the end, I could then use it on either machine, without changing drawbars or slugs, regardless of whether the MT2 arbours are tapped M10 or 3/8" BSW

The other advantage of the slug, is that the tooling will self eject easier from the Myford tailstock, without damaging the thread

Bill

Edited By peak4 on 28/01/2019 20:39:19

[Garry BellParticipant @garrybell53110]

Bill,thank you for taking the trouble to photograph your drawbar assembly, now the top end makes sense, I have no return spring or spring cap, I have not used the quill yet( not had enough air between a job and a vice to even think about drilling a hole or sinking a slot drill), first job on was the riser block dovetails, then copy the clamps, then machine the clamp pockets.it will be good to have the extra 120mm of space under the head, then I may get chance to use the quill, mine came with a Mitutoyo digital caliper attached to the quill,which could be useful in the future.
Bill I like your idea,
I think I might look into a drawbar with a 6mm thread they dont need much force to lock taper and easier to manufacture with a strong thread leaving enough material to make 3/8 and 10mm plugs as needed.
Once again thank you for your responses.
Garry

[peak4Participant @peak4]

No problem Garry, with the sort of stuff you've done, I'm sure you're able to come up with a cap design yourself.
Quite happy to pull mine out and measure it for you, no problem.

Just let me know, but to make sure I don't miss a post on here, send me a private message as well to remind me.

Bill

[Garry BellParticipant @garrybell53110]

Hi Bill, what would be a real help would be the diameter and unsprung length of the spring and SWG or dia of spring steel itself.
On a different note, I bought an old Turner Universal tool and cutter grinder last night, it looks interesting, delivered Saturday, I cant wait.

[peak4Participant @peak4]

Posted by Garry Bell on 29/01/2019 15:16:32:
Hi Bill, …………….
On a different note, I bought an old Turner Universal tool and cutter grinder last night, it looks interesting, delivered Saturday, I cant wait.

Hope it wasn't you that's just beaten me on the Olympus E-1 as well was it?

Let me know if the Turner doesn't suit you.

I'll sort out the measurements when I get back home to Buxton, which might be rather dependant on the weather.

Bill

[Chris GunnParticipant @chrisgunn36534]

Bill thanks a lot for the Centec manual link, I have just acquired 2 machines, 1 is a 2A horizontal, the other is a 2B with a vertical head and power feed, all on the big base with drip tray. I will have to see what they are like and decide which one to keep. They are both 3ph, 380v so I will need to change the motors. Would you happen to know if the power feed motor is a standard frame size?

Chris Gunn

[peak4Participant @peak4]

 

Posted by Chris Gunn on 29/01/2019 19:38:43:

Bill thanks a lot for the Centec manual link, I have just acquired 2 machines, 1 is a 2A horizontal, the other is a 2B with a vertical head and power feed, all on the big base with drip tray. I will have to see what they are like and decide which one to keep. They are both 3ph, 380v so I will need to change the motors. Would you happen to know if the power feed motor is a standard frame size?

Chris Gunn

Chris, in my case I run the main motor off an inverter, but the table power feed motor was, like yours, a 415v one with no accessible star point, and I didn't have a suitable inverter available.
At the time I was converting it, I had a broken leg, so going shopping for big heavy bits was a bit tricky.
At the moment I've got a normal single phase motor as the table feed, but it's not ideal for at least 3 reasons.

It's bigger and heavier than the original, for a similar horse power output, so with the table travel at max to the right, there is a noticeable tilt on the table; not a lot, but enough.
Also to get a different motor to fit, it clearly has to be a flange motor, but the actual output spindle needs turning down with a couple of steps and a through hole for a pin.
Gary Wooding on here has dived in and found the star point and re-wired his machine accordingly, so it runs off an inverter, See the photos in His Album

Personally, with the price of inverters being as low as they are at the moment, I'd not change the motors.

Swapping out the power feed one has certainly caused me some issues, and I intend to revert to the original when I get the time, either by doing the same as Mr Wooding, or by using one of the newer Far Eastern inverters with the 415V output.

Bill

Edited By peak4 on 29/01/2019 20:02:16

[Garry BellParticipant @garrybell53110]

Hi Bill.
Not me with the Olympus, I am a Nikon man, started at 17 with an Olympus OM10 went from there to Nikon D90 and stayed with it, I could get on the never ending money pit of camara upgrades, but my eyes are just not good enough to justify it, who’s are?
Garry.

[duncan webster 1Participant @duncanwebster1]

If your motor is built into the cabinet I strongly advise you to stick with 3 phase motor, a single phase motor makes the cabinet vibrate like mad and you need ear defenders. Mine was transformed by fitting 3 phase. As others have said you'll get an inverter for less than the cost of a singe phase motor, provided tat is you can reconnect the existing 3 phase as star.

I have a stepper motor driving the table, with the inevitable Arduino really handy to be able to wind the feed rate up and down

[EmgeeParticipant @emgee]

I think you mean Delta Duncan ?

Emgee

[duncan webster 1Participant @duncanwebster1]

Of course I do, just testing!

[peak4Participant @peak4]

Garry, I'd forgotten I was a member, there's also a Yahoo Group for the Centec with a few files on there as well

Bill

[Garry BellParticipant @garrybell53110]

Hi Bill, I will request to join the group, thank you, you are most helpful.

Garry

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