Member postings for mark smith 20

Bazyle , it is a very tight fitting bush, but as you say i dont really see why it needs so much contact area in the casting (along its full length). It doesnt spin or anything,its just basically a guide for the worm shaft.

One thing i wondered is why all those thrust washers are pinned to each other and the bushing and outside locking nut ,with oil grooves on one side of each ?? Anyone suggest a reason as they are tiny and fiddly.

In fact im totally confused by them, i mean if they are all pinned to each other and the bushing which doesnt move ,how is the locking nut supposed to turn/tighten  as it also has the two pin holes. The pins arent mentioned in the parts list neither is one of the thrust /oil washers. I only have 3 washers???

Edited By mark smith 20 on 18/12/2016 18:38:10

Edited By mark smith 20 on 18/12/2016 18:54:19

Thanks Michael . i dont really see much use for pins as its not moving and is just really a bush for the worm shaft.

If you plan on threading the back plate you can hold the back plate by the boss and bore out to the correct diameter ie. 39mm or 1 17/32".

Then you thread the hole for 1 3/4" x 8 whitworth right through the back plate.(making sure the thread tool can do this without hitting the chuck.

Once youve done this you mount the back plate directly on the spindle with the boss facing you. But using a temporary spacer (a piece of pipe or something just slightly bigger than register diameter and of the right depth minimum 0.17"  according to your measurements ) between the register and the back plate ,so that the boss side is clearing the spindle nose end..

This will allow you to machine /bore out the short area for the register, which you can keep taking off turnng around and checking until you get it right and its seating properly on the spindle register.

Once you have the back plate on the spindle you can then go about truing up the surfaces ,turning the chuck register and doing the mounting holes etc..

Edited By mark smith 20 on 18/12/2016 15:37:52

Edited By mark smith 20 on 18/12/2016 15:42:33

Edited By mark smith 20 on 18/12/2016 15:48:45

Edited By mark smith 20 on 18/12/2016 15:50:40

Hi Sean i cant understand the thread gauge, is it a BSW gauge and is it definitely 8 tpi? The thread looks flattened slightly on the top. G often refers to whitworth pipe threads which can be 7 tpi.

Could you possibly take a photo like this,which shows my southbend nose which is 1 1/2 x 8 UNC (but 60 degrees).

Edited By mark smith 20 on 18/12/2016 15:22:56

Hi Michael , thanks and would you use a few  pins as well around the circumference of the joint??

Edited By mark smith 20 on 18/12/2016 11:29:34

Ive decided instead of making the whole bush with flange ,that it may be easier to make the flange with a shorter round section and fix it somehow to the original main bushing body. (as the bushing is totally intact minus the broken off flange.)

Anyone have an idea what would be the best way of securing this ?

If i turned down the outside end of the bush to about half thickness and made the flange with a sleeve bored out to mate with the original bush. I could super glue it and ten maybe blind pin it .

Edited By mark smith 20 on 18/12/2016 11:14:33

Edited By mark smith 20 on 18/12/2016 11:14:58

Edited By mark smith 20 on 18/12/2016 11:21:48

But whats the diameter of the boss?

45mm should be ok, does the back plate have a boss on the back or is it full width?? I was thinking if it had a boss you could put it in the 3 jaw depending on the size of the 3 jaw using outside jaws?

The above hole that need bored is just over 1 /12" , more like 39mm  or 1 17/32"

Also are you certain the spindle nose is BSW thread ie. 55 degrees and not UNC 60 degrees?

Edited By mark smith 20 on 17/12/2016 19:56:01

Edited By mark smith 20 on 17/12/2016 20:14:41

Sean you could thread it internally but its a bit harder than outside threading. What is the total depth of the back plate ?

Is it over the 1.6" depth you need?(according to your measurements.)

You need to bore out the back plate  right through somehow to 1.5" ,then you could thread it  for 1 3/4" x 8. You could then screw it on the spindle nose and machine the register.

Edited By mark smith 20 on 17/12/2016 19:44:21

Edited By mark smith 20 on 17/12/2016 19:49:01

Hi Sean, sorry to hear , are you able to send the back plate back? i think RDG have a 7 day returns policy.

Looks like you have a 1.75" x 8 thread, do you know when your lathe was built approx.??? Apparently Clausing 4900 series lathes made in the 1960`s had that larger thread.

Lathes .co.uk do sell the 1 3/4" x 8 back plates for Smart and Brown sabel lathes which have that size thread but they are expensive..

Edited By mark smith 20 on 17/12/2016 19:08:44

I found this the other day when looking for dividing info. There may be other books.

free to view:

**LINK**

Edited By mark smith 20 on 16/12/2016 09:32:13

HI Sean, its the same guy who posted on your Steadall thread, called Robert Hamblin who i think is in New Zealand. He made the comment back in 2008 on the practical machinist forum. He said the Boxford nose is the same size and that none of the Clausing spare parts fit the Fortis lathes.

Ok Sean, let us know when you have the back plate and/or chuck.

The register on my chuck is 82.5mm so when you get a chuck you may have to reduce the turned section on the backplate down to match your chuck (which may be the same as mine or slightly different)which is easy as long as you go slowly and keep checking for a reasonably tight fit..

Which back plate did you order and which chuck?

Sean, the chuck you point to on ebay won`t fit your lathe as its Myford 1 1/8" x 12 direct screw on.

The one i pointed to is the same but needs a boxford back plate which you would have to purchase seperately.

£66 for the chuck i point to and £20 for a back plate comes to £86 which is £24 cheaper than the one your looking at.

You`d need a chuck key or two but very easily made up from a couple of bits of scrap round bar.

Hopefully all you`d really need to do would be skim the back plate register to the size on the chuck then drill and tap four holes for the mounted machine screws. You would also learn something in the process .

An 8" wouldnt be too big for your lathe as its 12" swing but you would still need to fit it to your 1 1/2" x 8 BSW spindle nose.

You could use a 6" 4 jaw and get a faceplate if you need to turn anything bigger  which is what i do. I have one of these:

http://www.ebay.co.uk/itm/genuine-BOXFORD-LATHE-FACEPLATE-WILL-FIT-THE-AUD-BUD-TUD-lathes-/201746543751?hash=item2ef907f487:g:BL8AAOSwux5YTV9J

Edited By mark smith 20 on 13/12/2016 11:14:13

Sean, from what ive found out your spindle nose should be the same as Boxford, that is 1 1/2" x 8 whitworth (BSW),

And this was mentioned on a forum from a guy who owns two of these Fortis lathes.

So all you need is a 6" 4 jaw such as the one i linked to above (£66 including shipping) and a suitable boxford back plate. I would just buy one around 4" diameter and with the boxford thread but no screw holes(around £20).

If your register is slightly small on the backplate simply mount the backplate on your spindle backwards with a spacer so you could turn the register . (though according to the guy on the forum i mentioned boxford stuff should fit directly onto the spindle nose,so may be no need for it)

Turn the register on the backplate to fit the register on the chuck. Then just drill and tap the back plate for the four mounting bolts.

Sean , the chuck you linked to is only 1" according to the seller. I thought you said its 1 1/2" x 8 ??

Hi Sean, i use one on my south bend and i like it , they are a good make and quality. They are often on ebay . You can buy threaded back plates for boxford which would probably fit yours such as :

**LINK**

Its best to skim the back plate on your lathe anyway even if it comes with a backplate already attached. That way you ensure its got minimal run out . Though not awfully important with an independant four jaw as you`ll dial it in anyway each time you use it.

Mine came with my lathe but looked to be unused as the jaws are still pretty tight and unworn and it had a boxford backplate on which didnt fit properly on my spindle nose.(until just recently when i single pointed the threads to 60 degrees UN.

I just made another chuck key for mine as its far quicker dialing in using two opposing chuck keys.

Edited By mark smith 20 on 12/12/2016 18:46:13

Theres one here in good condition but needs the back plate.Price seems reasonable.

http://www.ebay.co.uk/itm/6ins-Bernerd-4-Jaw-Chuck-/302163473722?hash=item465a58b53a:g:1t8AAOSw6DtYTUZs

Edited By mark smith 20 on 12/12/2016 18:50:43

I had mine in a large 2 1/2 litre glass bottle from a chemical supplier, it had a screw on plastic top. Never noticed it evaporating ,but i know it would quite quickly if the top was left off.

I can only think that the bottle seal supplied was not very good. You shouldnt be able to smell it through the top if its effective. Strange !

Its evaporation is a problem with paint strippers which is why it was always mixed with something that looked like wallpaper paste and best to cover with cling film.