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Member postings for Richard Jarvis

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

Thread: New Chuck won’t screw on
02/08/2021 12:58:59

When I first started thinking about replacing my original Chuck about two months ago, I recall the RDG advert stating that the backplate was machined by one of there engineers. I might be wrong but I am not convinced that RDG machine the backplate themselves, but they come with the Chuck from the manufacturer. I might be totally wrong of course.

Thanks Richard

01/08/2021 08:46:38

The disappointing bit for me is that they were adamant no problem existed and it was ok, even though someone else had exactly the same problem that week. It has been mentioned faulty goods should be sent back, but delivery to me can take over a week and if I have to stand return cost you are soon out of pocket.

Thanks Richard

Thread: ARC Eurotrade
30/07/2021 21:07:55

I will note that for the future

Thread: New Chuck won’t screw on
30/07/2021 20:05:57
Posted by brian jones 11 on 30/07/2021 15:13:02:

Referring to the OP Richards post I had this response from Tracy tools

Many thanks for the email, we can only offer it in standard UNF which we sell all the time for the Myford backplate, it should really be a whit form thread but over the years we must have sold hundreds and we always let people know and we've never had anyone say it didn’t work, so I think your be fine with it. 
I could quote to have a whit form tap manufactured but the cost would be around the £150 mark which doesn’t always seem worth it.

https://www.tracytools.com/taps-and-dies/UNF-taps?product_id=932

£14 same as chronos

I got chastised for suggesting 1 - 1/8" UNF x 12

more work needed here to show comparison fits, of course the clamp surfaces between threads will only be at the crest - should we get stressed about this?

Back to the drawing board Batman.devil

Thanks Brian, today I put a piece of silver steel 10mm in the Chuck and used dial indicator to find a 2 thou run out. I have seen some people loosen backplate bolts and tap the Chuck to try and reduce the error. I found I could move the Chuck on the backplate register by just over 2.5 thou, is that fit tight enough?. If not I will get another backplate and have a go at machining, will a steel one do or is cast iron best?. After putting Chuck on and off a few times it goes on easy now.

Thanks Richard

Thread: ARC Eurotrade
29/07/2021 07:46:13

Thank you for that Ketan, I was using an iPad and could not get past the first page. Solved it I hope by doing a security update that was due for install but had not automatically done it.

Thanks Richard

28/07/2021 21:29:55

Anyone having problems logging in to the ARC website?

Thread: New Chuck won’t screw on
28/07/2021 13:04:13
Posted by JA on 28/07/2021 12:56:21:

Do RDG/Myford read these postings? Perhaps they should.

JA

Well they did not answer my last correspondence seven days ago so I decided to have a go myself with help from the group.

28/07/2021 12:58:23

Have you checked the machining on the face plate?, I managed to get a better surface finish using a 12mm shank tool with what I think is a brazed tip. I tried a HSS but that left as bad a surface as original, that might be the operator at fault as I had attempted to grind it myself.

27/07/2021 22:05:49

I tried a dti on the backplate and found about 1 thou runout but the needle was constantly moving due to a bad surface finish. I will try to skim it tomorrow. Hopefully this picture will show the surface.eb6b87cc-2a19-4044-a230-45ed90234507.jpeg

25/07/2021 10:00:32
Posted by not done it yet on 25/07/2021 08:52:00:

Then check the runout of the front face outboard of the step and skim that part true if needed. Then refit the chuck.

Steady on! You’re not suggesting that rdg would get that wrong as well? I am very selective when buying items, so don’t often buy from that source. I would guess that only s small proportion of parts are actually checked at the time of manufacture - and likely no further checks at all (unless a complaint arises? ).

But the complaints fall on deaf ears they told me someone else had the same problem as well but when they tried the chuck back at RDG it was ok!. I have bought a few bits from them over the last 18 months but maybe not anymore.

25/07/2021 09:45:38
Posted by old mart on 24/07/2021 22:25:18:

Well done, you will find that in the real world, the fit is better when it is a bit on the loose side. You should remove the chuck from the backplate and screw the backplate on and off the spindle several times to settle it into place. Then check the runout of the front face outboard of the step and skim that part true if needed. Then refit the chuck.

The chuck fit certainly can’t be described as loose, in fact the thread will definitely be doing the locating. I did put a dti on the circumference of the chuck and found two high spots nearly 180 degrees opposite to each other, I am not sure that’s right,reading it it doesn’t make sense  I will check as you say when I have fastened the lathe back down as I am in the process of lifting it a couple of inches. I wear glasses and my focal point was making me bend down causing back pain.

Edited By Richard Jarvis on 25/07/2021 10:03:13

22/07/2021 11:37:43

The Chuck would only go on half a thread, anyway I have sorted it no thanks to RDG who appear to have washed their hands of the problem. After reading Howard’s post it got me thinking as to wether in my dads box of taps and dies I had the relevant tap, but the nearest was 3/4 x12 tpi. So I rolled the chuck on the bench with the tap seating on one edge of the thread and after 1 1/2 hours managed to get the chuck to screw fully on. I had oiled the thread and this clean oil kept turning black, so I presume the root of the thread was full of Iron powder and the tap must have cleaned it out. Thank you very much for all the replies, nowto go and put a dti on it and check for any run out.

Thanks Richard

22/07/2021 10:09:15
Posted by Howard Lewis on 22/07/2021 09:30:27:

Maybe the thread needs to be truncated by a couple of thou, to prevent root / crest interference?

Put a substantial bar into an existing chuck.

Skim to obtain a concentric diameter.

Clamp the new chuck to the bar.

If the chuck on the mandrel is a 4 jaw, clock the register of the new chuck and centre as accurately as possible..

Skim the thread of the new chuck, to take out just a thou or so.

With a thread depth of 0.053", the core diameter should be 1.019", so you are looking to enlarge the ID of the thread to about 1.022 / 1.023.

Possibly, before you start work on the new chuck, turn up a piece of bar to 1.022/3" to use as a plug gauge.

Hopefully, the truncated thread will allow the chuck to screw fully onto the mandrel.

Howard WHY do I only spot the typos after posting?

Edited By Howard Lewis on 22/07/2021 09:31:40

Thank you for that but it’s way out of my capabilities at this time, I do believe the problem is the root of the thread and or the fact that the start is not fully formed. I did ask from which side the backplate is threaded from because I think the end I am trying to screw it on from is the finish of the thread and it has not been formed fully.

21/07/2021 22:46:20
Posted by duncan webster on 21/07/2021 22:23:29:
Posted by Richard Jarvis on 21/07/2021 16:50:43:

........., told supplier only to be told that they are machined on a myford and then checked on two other spindles to check fit. .........

Thanks Richard

If I were making backplates for a living I'd use something more 'industrial' than a Myford. Don't get me wrong I'm on my second, but only as a hobby

Not that this helps, but the backplate I bought from RDG/Myford fits lovely. If you divulge your approximate location there might be another Myford owner near you and you could try it on their machine. With a bit of care you can do this Covid secure

Edited By duncan webster on 21/07/2021 22:23:50

Edited By duncan webster on 21/07/2021 22:24:25

Thanks I’m in Orkney, I did not realise that was not shown. I have tried two face plates and a spindle nut from an Amollco mill so am sure it’s not my spindle at fault because they all fit ok.

Richard.

21/07/2021 22:34:18

This seems to be a common fault, I sent them some pictures earlier so I will see what tomorrow brings. Thank you for the replies.

Richard.

21/07/2021 19:05:38
Posted by bernard towers on 21/07/2021 18:24:17:

All backplates that I have bought from non genuine suppliers have needed work!!!

Without mentioning where it came from, they should know how to make the backplate fit a myford.

21/07/2021 18:45:30

You will all be getting fed up with me now, only one picture downloaded, here goes this is the new Chuck.

Thanks Richard97135152-f106-468a-848a-0d885204ac79.jpeg

21/07/2021 18:35:18

e25aee9f-5063-4cbb-8f17-1bc0fdda111f.jpegThe Chuck on the left is the new one, the first thread is nearly square but on my old one on the right it seems to be formed correctly or does that not matter. I found a thread gauge and they both read at 12 tpi but I am sure the gauge hits the top of the threads on the new chuck but I think the gauge has a small gap between it and the top of the thread on the old one, I think the thread is not deep enough.Thanks Richard 

Edited By Richard Jarvis on 21/07/2021 18:40:14

Edited By Richard Jarvis on 21/07/2021 18:42:43

21/07/2021 18:05:43

7560fbfb-f111-43ca-bbe9-ac026cd0f81b.jpegRight it says file for video too big, but I managed to do pictures, I have marked the start of thread with pen it starts at 12 o’clock position and my chuck is a full turn to form the thread whereas new chuck seems to have it formed just after half a turn. The way I have written that is not very clear hopefully you can decipher my poor explanation. I have managed to post the same picture twice but I can’t see how to delete the second copy.ac21575e-8dde-404e-a37d-05c7fbf059cb.jpegac21575e-8dde-404e-a37d-05c7fbf059cb.jpeg

Edited By Richard Jarvis on 21/07/2021 18:07:17

21/07/2021 17:37:03

I am trying to post two pictures and a video of me trying to screw on the Chuck but am struggling, just reading the info on posting pics. I have done the thread impression and it seem to be the same tpi but I don’t think it’s cut deep enough.

Edited By Richard Jarvis on 21/07/2021 17:46:27

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