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Member postings for John Coates

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

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Thread: Have broken a cast bit of my lathe - any hope of a repair?
13/02/2011 23:00:00
Found a site describing split cotters
 
 
Strangely enough the locking mechanism for the cross slide uses a brass version of this principle, a brass barrel with the end scalloped out which presses against the bar the cross slide runs in when the locking bolt is screwed in
 
13/02/2011 22:18:32
As Guy Lautard"s books are pretty expensive just for the split cotter design can anyone describe it to me or sketch it please?
13/02/2011 13:11:11
Keith, ady and Steve
 
Point taken. I think a bit of redesign should go along with the work to restore it (cosmetically at least) to original
 
If my brother in law says it's weldable with the rods suggested by Paul then I think I might get him to do it so it looks original, but then design something else to actually lock the tailstock
 
First thoughts are a kind of handcuffs arrangement that clamp over the two bars but then each cuff has a horizontal lug facing outwards that is slit with a locking screw or bolt. At least that way the forces are distributed evenly rather the locking being done on only one of the bars, as with the original design
 
Thanks everyone. I really am feeling an awful lot better now about my cock up and have stopped beating myself up about it
 
John
13/02/2011 13:04:28
Posted by _Paul_ on 13/02/2011 12:33:49:
From the pictures it looks weldable, if you are handy at Arc welding you could try "Magna 770" rods after V-Ing the joint out then short welds & peen after every weld.
I'm no expert but have done some creditable repairs on "unknown" dirty cast iron with these rods.

I've got a 160 Amp MMA stick welder and my brother in law has the skills (it's his day job!) so if I got some of these would they be the right ones?

13/02/2011 07:54:41
Posted by Terryd on 12/02/2011 23:02:54:
Any chance of posting a couple of photos in your album? There are some other methods of repair you could use but it depends on the casting.
 

Now added

Here is the underside (sorry for the out of focus)

And here's the broken lug

Thanks again everyone
 
John
 
12/02/2011 21:54:17
Posted by Keith Long on 12/02/2011 11:02:20:

It looks to me as though the clamp that you are talking about is under the tail-stock at the rear, and the lugs that give the clamping action project downwards.

Yep that's how it is. There is more metal in the lug than in the bit of the casting that broke hence the over tightening caused it to snap where it had the least strength. My brother in law is a coded welder so I shall ask him.

Thanks for all the suggestions. After a day with the kids away from the garage I feel more positive about things and can see a way out of this. When it happened this morning about 8am I could have happily punched myself for being so dumb at over tightening it.
12/02/2011 10:41:50
I thought my hamfistedness was receding into the past but I was wrong
 
I have broken the locking mechanism on my tailstock. The lathe is a roundbed Barker from 1947 so finding a spare is probably not an option. Imagine two parallel iron bars with the tailstock base being two round sleeves over them with a flat jointing piece.
 
In one of the sleeves is a slit to allow a handle to close it to secure the tailstock against the bar. Well I have over tightened the handle and snapped the casting so the opposite side with the thread in has broken.
 
After nearly punching myself I began to think of possible solutions:
 
1. Have a new one cast but goodness knows what that will cost
 
2. "Glue" the two halves and then drill small holes to take carbon steel rods which will be glued or somehow welded in or the whole until somehow heated up to get them to bond
 
Can anybody suggest anything else or advise on the above?
 
I can get by with a temporary fix using timber stays of several lengths to brace the tailstock against the end of the lathe
 
Thanks for any help in this time of crisis
 
John
Thread: universal pillar tool by george h thomas
04/02/2011 20:09:30
The book refers to a "Sensitive Drill Attachment" - is this what you mean?
 
Chapter 7 - Sensitive Drill Attachment
Chapter 8 - Small Components for the Drill
Chapter 9 - Completing the Drill
Chapter 10 - Motors and Belt Drives
 
Thread: Time for new forum software.
29/01/2011 16:53:55
Posted by blowlamp on 29/01/2011 14:59:59:
Also, I believe IE9 will become the next standard - whether we like it or not - in the same way the other IEx's have been in the past.

Thankfully the rest of the world does not agree with you for the reasons stated above about Microsoft's arrogance and consequently blighted, bloated and bug ridden products. I use Firefox on Linux and Safari on Apple's Leopard and this site causes me no problems. Both of these follow the published international standards which is maybe why they work. Crap software from Microsoft is not a reason to change the rest of the world, despite what Mr gates thinks.

Thread: Tailstock tap holder using a posilock collet chuck
25/01/2011 22:52:01
I have been getting by without a tailstock die and tap holder during my learning phase (since May 2010) but decided to make one about month ago. It is still work in progress but the die sliding body and die holders are done, they just need tapping for the grub screws.
 
Anyway I decided to make a new securing nut for my toolpost and wanted one with a permanent handle. Anyway I needed to tap the 1/2" thread in the body for the toolpost pillar. Hit the usual problem of having no tailstock tap holder to get the tap true in the workpiece
 
Then realised that my posilock collect chuck was MT3, the same as my tailstock, and that if I could turn a collet with a round bore for the tap shank and square hole for the tap end, I could hold the tap securely in the collect chuck in the tailstock.
 
Anyway have finished this today. The first collet is not pretty but it is functional and taught me the process to follow and what is important to get right. The tap sat true in the collect chuck in the tailstock and I got the thread properly started in the workpiece.
 
And I don't need to make a tailstock tap holder for a while longer
Thread: Dickson Tool Post . - can it be drilled ?
20/01/2011 13:57:14
Posted by WALLACE on 10/01/2011 16:20:49:

Any ideas if they're through hardened and impossible to drill ? !
I bought a Dickson type QCTP from Chronos and bored it out from 7/16ths to 1/2". We (folks on here) figured out in the endit was case hardened
Here's how I did it:
Thread: Motorcycle wheel spindles
13/01/2011 12:37:59
Usually spacers are made to adapt a wheel to the motorcycle to retain the original spindle and fixings (nuts, washers, chain adjusters). The best way is the principle of captive spacers where larger diameter bearings have spacers permanently fixed to speed up wheel changes. This not an option for you? And you have checked the alignment of the brake discs relative to the brake calipers as these can need spacing as well
 
I have a 1999 Kawasaki ZX7R onto which I am putting the front end (forks, calipers, yokes) from a 2007 ZX14 and swingarm from a 2005 ZX10R so am dealing with the same issues
Thread: Switching between lathe and mill (3 phase)
11/01/2011 22:15:08
Posted by _Paul_ on 11/01/2011 21:12:18:
A switch would be nice.

Looks like your reply from Drives Direct supports the individual plugs option rather than the switch. Had bought the industrial plugs and a wall socket from Screwfix so will go with that option
 
11/01/2011 22:12:30
Posted by KWIL on 11/01/2011 19:08:19:
Are both your motors exactly the same? If not, how are you going to setup the internals of the inverter to suit both?

 Lathe is a 1hp motor (0.75kW up from the original which I guessed was 3/4 hp as it was so old the plate was indistinguishable so I went with the same motor as on  Myford) and mill is 0.55kW. I have a remote control pod made by Drives Direct which has Fwd/Stop/Rev, variable speed and Run/Jog so I can set the frequency (Hz) before switching to Fwd or Rev with a 1 sec ramp up to full speed. With the lathe I have worked out the RPM from 1Hz to 50Hz in 2.5 increments, printed this out and laminated it to put up in the garage as a quick reference. I will do the same for the mill and put that up next to the mill.

11/01/2011 22:04:46
Posted by LADmachining on 11/01/2011 17:55:44:
The idea of using an industrial plug to switch between the two machines is probably the most feasible idea, but then careful choice of the type of plug should be given to ensure the integrity of the screeing is maintained.

Ah - good point. I suppose the screening could be soldered to a wire that was connected to an earthing point 

11/01/2011 17:07:19
Having wired up the lathe to an inverter and put a 3 phase motor on it, I am very impressed with the variable speed control so want the same for the milling machine. But I want to keep with the one inverter so need a way of joining the screened 3 phase supply cable from the inverter to some kind of switch box that would then connect between the lathe or the mill
 
Basically the 3 phase SY cable would come out of the inverter to the switch box, the switch box would be either connecting the lathe or the mill (it could have an off position), and the screening wire for the in cable and the two out cables would be attached to some kind of separate earth point
 
Anyone got any idea of what sort of switch box I should be looking for? Early Google attempts have turned up nothing like I am looking for.
 
Fall back position would be both machines having 3 phase supply cables with industrial connectors on and I would unplug and connect every time I wanted to use a different machine
 
Thanks for any help folks
 
John
Thread: Phase Converter Which Type?
09/01/2011 20:26:00
Posted by John Coates on 24/08/2010 12:24:17:
A really useful thread btw folks as I plan to change my lathe and mill to 3 phase for the variable speed at some time in the future so this is great for my research
 

Which I've just completed and variable speed is fantastic 

Got a 1hp inverter from Drives Direct for £77 (ebay) then a 1hp motor  for £69 (ebay) and just finished wiring it all up today
 
And it's so much quieter so will be able to be in the garage without annoying wifey or neighbours. No more whining speed wheels
 
Got a remote control pod to wire in but wanted to check it all worked properly 
Thread: Milling Chucks
07/01/2011 13:20:03
Posted by The Merry Miller on 05/01/2011 17:24:07:
POSILOCK MILLING CHUCK SET
 
Can anybody out there cast an unbiased (or biased) opinion about the above.
 

 I bought one of these for my lathe and mill in MT3. Been very happy with it for using endmills and slot drills up top 20mm dia. It was a good price from Chronos and am very happy with their speedy service

Thread: Late delivery of magazines due to adverse weather
05/01/2011 12:09:53
Mine arrived yesterday  but didn't get to read it until late at night as was excitedly wiring up my 3 phase motor and inverter
 
Thread: christmas presents
30/12/2010 20:59:22
A revolving centre on 1/2" shank for the boring head to go in the tailstock so I can offset it for  turning tapers
 
A "Keep calm and carry on" t-shirt which is a good motto for me when in the garage workshop, either metal bashing or motorcycle mechanicking
 
And just treated myself to an Evolution Rage circular saw to save me hours hacksawing through metal !
 
 
PS Peter - my diluted cutting fluid in an oil can also froze up ! 
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