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Member postings for Chris Pearson 1

Here is a list of all the postings Chris Pearson 1 has made in our forums. Click on a thread name to jump to the thread.

Thread: New Workshop Progress
18/08/2021 22:52:25
Posted by Neil Wyatt on 18/08/2021 20:47:23:
Posted by Chris Pearson 1 on 18/08/2021 18:41:50:

You need to know how to terminate it into the proper glands and of course, if you are fitting a new CU, it will need to be notified.

Yes, I understand the regs

Building Regulations (2010) or Wiring Regulations (BS 7671:2018)?

18/08/2021 18:41:50
Posted by Neil Wyatt on 18/08/2021 09:45:27:

I've tried reading up on SWA cables but it isn't clear if it would be OK to run one above ground between two buildings.

In this case it would be fixed to the low concrete block wall on which a wooden fence is fixed for most of the run.

Fixed to a masonry wall will be fine, but not a wooden fence please. That is because a wooden fence may rot.

You need to know how to terminate it into the proper glands and of course, if you are fitting a new CU, it will need to be notified.

Thread: calling 254 Myford owners
26/06/2021 21:48:23

My apologies if anybody objects to my thread drift.

Myford is offering some taper turning attachments, which seem to have been cluttering up their shelves. £400-odd could be a lot for something which you use once or twice, but nice to have even if never economically sound. smiley

20/06/2021 16:36:12

Or get somebody with a small Myford to do it for you.

Dare I say that an adaptor can be pretty useful if you want to keep the workpiece centred in the chuck and transfer to the dividing head?

Thread: Myford 254 S
12/06/2021 18:15:56

As others have suggested above, the 254 series lathes were fitted with a BS 4222 spindle nose. That defines the taper (1:4 on the diameter) and the PCD and size of the bolt holes. They are the same whether studs or cam-lock pins are fitted.

D1-3 back-plates fit the Myford spindle, but you will need to make up some studs with, as you have identified, an M10 x 1.5 thread. (The holes are 10.5 mm diameter.)

Then it gets more interesting. Don't assume that just because the thread on the spindle end of the studs is metric that the other end is. The cam-lock pins for a Pratt-Burnerd back-plate are threaded 7/16" x 20 UNF and not M11 x 1.25.

ETA: 7/16" x 20 = 11.11 x 1.27 mm. How do you think that I found that out? blush

Edited By Chris Pearson 1 on 12/06/2021 18:20:05

Thread: Myford 254 Plus toolpost type
14/04/2021 18:21:07

There was a Myford 254 rear tool post on fleabay recently, but surprisingly, with a starting price of only £90 it didn't sell.

I am also very pleased with mine. It's about the biggest lathe that will fit in my indoor workshop. Anything bigger would have had to go in the garage, which does not appeal.

I think very much better than the 7" Myford, but no more expensive!

Edited By Chris Pearson 1 on 14/04/2021 18:24:33

13/04/2021 22:26:01

One of the advantages of the 254 (plus) is that plenty of Super 7, etc. stuff can be used. The "elephant's foot" tool clamp, 4-way swivelling one, and "Dixon" one are common to both.

In practice, it isn't a problem, save when the pin which secured my parting off tool holder sheared. I am not sure that the baby lathe would have had enough power to do that - it might just have stalled.

Edited By Chris Pearson 1 on 13/04/2021 22:26:22

Thread: Strange Word...
14/11/2020 20:42:18

Neither "crossslide" nor "cross-slide" appears in OED. I suppose that the term really should be "across-slide".

Thread: Myford 254V Plus gearbox noise and vibration
07/11/2020 18:30:16

Are you able to measure the frequency of the vibration (against spindle speed)? That ought to give you an idea where to look.

Thread: Myford 254 oil leaking
04/11/2020 22:33:46

As far as I can recall, there is a wee hole at the bottom of the flange so that any oil which is carried into it may drain back into the headstock. There certainly isn't any form of rubber or scroll seal. The hole could be blocked by debris. I fear that dismantlement of the headstock may be required. Not an easy task!

Thread: Griptru wil not ad just
18/10/2020 18:41:37
Posted by ega on 02/04/2020 16:10:44:

It is apparent that the Griptru came in various forms.

I have recently acquired one, which has barely been used, if at all. Mine is the bespoke Myford one, so no backplate as such.

The adjustment is brought about by conical screws in the body bearing upon tabs which project forward internally from the base. If the body and base are clamped together tightly, it is difficult to see (i.e. IMHO impossible) how one could be moved over the other; but how tight is too tight?

On my particular chuck the screws which unite the body and base enter from the back, but with a separate baseplate, I imagine that they must enter from the front.

I have found that 1 Nm allows adjustment to be made with quite gentle force. 2 Nm makes the force a little more than I would like, but it is possible.

The next question is how tight do the screws need to be when turning? Possibly no more than 2 Nm. Remember that the manufacturers intend these chucks for grinding, so certainly not for roughing out. IMHO 5 Nm is plenty for a 4" chuck. The difference requires barely any movement of the screws.

If you don't have a torque driver, I would suggest that for adjustment, the screws be nipped up holding the short arm of a hex key between finger and thumb; afterwards just the normal good twist holding the long arm in the palm of the hand in the normal way.

HTH.

Thread: Operating a Myford 254 lever collet chuck
20/09/2019 10:28:48

I am puzzled by the operation of this chuck and I can find nothing on line. It appears to have been made by Pfander. This is what I have been doing:

- load collet (163E)

- fit closer loosely

- place workpiece in collet

- tighten closer so that the lever has about about 1/4" of slack

- push lever to right - this locks the collet

To remove the turned article:

- push lever to left

- undo closer with spanner

My expectation was that a collet would be mounted and closed to a sliding fit over the workpiece. The lever would then lock it in place and subsequent operation of the lever in the opposite direct would release the article.

Am I doing something wrong, or am I expecting the chuck to do something for which it was not designed?

Edited By Chris Pearson 1 on 20/09/2019 10:29:20

Edited By Chris Pearson 1 on 20/09/2019 10:29:51

Thread: Servicing a Myford 254
22/05/2019 21:42:56

Well, it's now in pieces and I shall be off to my usual bearing supplier tomorrow.

There is quite a bit of fine, and not so fine, swarf in the bottom of the headstock. It is mostly below the right hand bearing, which shows signs of wear, but it doesn't seem to be enough to account for the muck. There is no obvious damage or wear elsewhere.

Photos to follow.

Thread: Myford 254 Apron Rebuild
12/05/2019 18:08:42
Posted by duncan webster on 04/05/2019 22:31:27:

"OD = (N+2)*1.5 is only an approximation, which may be better for larger gears."

well HPC, who actually make gears quote 16t 1.5 MOD OD = 27.00 mm

I take the point. If one calculates module = 4/9 x tooth depth, the result is 1.46.

In theory, as Duncan points out, the reference diameter is 24 mm with a tip diameter of 27 mm and a root diameter of 20.25 mm so the scale of the pinion has been reduced by a factor of about 5%.

I found out today that this pinion was routinely replaced during refurbishment, which probably explains why they are in short supply as well as being, perhaps, a weak point.

04/05/2019 19:59:35
Posted by duncan webster on 04/05/2019 19:08:44:
Posted by Chris Pearson 1 on 04/05/2019 15:40:36:

Just in case anybody else has this problem ...

In my case the pinion is acceptable, but the shaft is a little worn..

The tip diameter is 25.6 mm. The root diameter is 19.05 mm. It is module 1.5 with a 20 degree pressure angle.

Some of the other gears in the apron seem to be 20 DP and 14.5 degrees or at least they mesh with standard change wheels, but this one is clearly not.

OP says the gear has 16 teeth, if the module is 1.5 then the OD should be (16+2)*1.5 = 27 mm

My metric 254 moves the saddle 25mm for one rev of the handwheel (checked with DRO), which suggests a circumferential pitch (or some clever gearing), but 6 teeth on the rack is 25mm which is a very odd CP

OD = (N+2)*1.5 is only an approximation, which may be better for larger gears.

The pinion meshes with a 48 tooth gear which drives an 18 tooth pinion which meshes with the rack.

Funnily enough, the imperial rack measures 25.4 mm over 6 teeth. So one turn of the hand wheel turns the big wheel 1/3 of a turn, which equates to 6 teeth of the rack pinion.

It has been interesting fettling my 254. In many ways, they are very basic lathes, but they do seem to be well made. One exception may be poor lubrication of the handwheel shaft, but in the absence of oil, no lubrication system will work. smiley

04/05/2019 15:40:36

Just in case anybody else has this problem ...

In my case the pinion is acceptable, but the shaft is a little worn..

The tip diameter is 25.6 mm. The root diameter is 19.05 mm. It is module 1.5 with a 20 degree pressure angle.

Some of the other gears in the apron seem to be 20 DP and 14.5 degrees or at least they mesh with standard change wheels, but this one is clearly not.

Thread: Servicing a Myford 254
03/05/2019 14:53:18
Posted by Hopper on 03/05/2019 06:54:19:

Hi Chris and welcome to the forum. I assume (and I may be wrong of course) from your questions that you are more toward the novice end of the skill-levels scale. So you might be best to not go pulling the spindle and bearings out of your lathe at this stage. It's not really a beginner exercise. ...

But your vibration as has been said is more likely to be created by something else in the drivetrain. Taper roller bearings are usually very long lived and problem free, if adjusted right and kept lubricated. ...

One big source of vibration on old machines is old drive belts....

I have replaced a fair few bearings in my time. The worst one came out of a Jaguar's rear hub - the rollers looked more like gallstones.

Thank you for suggesting the drive belt - even though it looks fine, replacing it won't break the bank.

03/05/2019 14:46:07
Posted by lfoggy on 02/05/2019 23:56:36:

There is an oil bath in the apron that lubricates the power feed gears. There is a plug for draining the oil at the bottom of the apron and access to add oil at the top.

Yes, thank you, I know about that, but why does the leadscrew nut have what looks like a reservoir? It cannot be one because the oil would simply run out. Odd!

20190503leadscrewnut.jpg

03/05/2019 14:30:16
Posted by lfoggy on 02/05/2019 20:12:42:

I've never had to do any servicing on the spindle bearings themselves. Are you sure your vibration is coming from the spindle bearings and not from elsewhere? Is the vibration present when you have the lathe in direct drive without the feed engaged? Have you checked that the drive pulley is properly coupled to the end of the spindle? This can come lose and vibrate.

Does your owners manual have the full exploded diagram of the headstock assembly? If you did want to dismantle it this would be useful. If you don't have this I can send it to you.

Ifoggy, thank you for the response. Yes it is present in direct drive and absent with the belt removed - I have replaced the motor's bearings. Yes, pulley is tight.

Yes the manual has the exploded diagrams. There is no obvious means of adjustment.

02/05/2019 14:05:10

I'd be most grateful for advice on a couple of matters in connexion with servicing a Myford 254 please. FWIW, mine is a 254+ Varispeed.

(1) I wish to remove and inspect the spindle - there is a hint of vibration and the oil in the headstock was not entirely clean. I cannot detect any play in it. Removal of the spindle may be fairly easy, but putting it back may be more difficult. Can anybody advise on, for example, whether any preload is required for the taper bearings.

(2) There is what looks like a small oil reservoir on top of the leadscrew nut. I don't think that it can be a reservoir because (a) there is no obvious way of filling it save for removing the apron, and (b) any oil would flow straight out.

If have a copy of the owner's manual, but was there ever such a thing as a service manual?

Many thanks in anticipation.

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