smith barker and willson lathe

hi all i need advice on my toolpost.first up it is about 6x6inches square and a good 1 inch thick metal so we have a good amount of meat to work with,running a straight edge over the top and bottom faces it has one hell of a dip in the middle and i was toying with the idea of putting it in the mill and giving it a light shave.i have tried already with oil stones and this is beyond that.is my idea good or a big no no??

I'm sorry, I'm lost.

Would it be possible to provide at least a couple of pictures?

Thanks!

Paolo

Here is how to to help with the photos

https://www.practicalmachinist.com/...res-south-bend-forum-372508/?highlight=photos

have fun

hope these pics helpthe large flat areas are dished in about 10 thou roughly sorry but you have no idea how much trouble i have doing this

The only important places on a tool post are the base where it sits on the topslide, (which IMO needs to be very slightly concave so as not to rock around the centr bolt) and of course the tool seast (where the tools sit) again the more contact the better.

In 99.99999999% of cases, the top of a TP doesn't matter a single iota, .............and given the age of your SBW looks pretty damn good to me.

In your shoes I'd leave the top alone, and concentrate on the 2 afore mentioned faces.

If you do have to skim the base of the TP, IMO it's far easier (and often a better job) done in the 4 jaw on a lathe (and yes with a little creative tool holding you can use the lathe it's fitted to

Of course YMMV but you did ask

thank you limy you are right it is concave on the under side so i will leave it alone after your good advice cheers and thank you so much for going to the trouble to help out thank you

My pleasure mate, .where in Aus are you? my late Mum was from Ballarat way.

i am from kinglake ,victoria but one of our daughters lives in ballarat

Now didn't I say he was a good bloke.

Limy Sami said:

Now didn't I say he was a good bloke.

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Just a shame that you didn't catch it.

camscan said:

Just a shame that you didn't catch it.

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Who rattled your cage.

Getting back to the tool post issue.

I'd be inclined to cut a proper relief for a reasonable diameter around the centre stud to ensure that clamping occurs on the outer part of the tool post. Perhaps a diameter something between 1/4 and 1/3 rd of the width of the top slide would be appropriate.

Many years of tightening down the tool post tends to distort the top of the top slide a little. Every old one I've seen has been convex, rising a little in the centre around the stud, in greater or lesser degree. This means all the force needed to stop the tool post rotating has to be supplied by a fairly narrow ring. I imagine the process starts with initial over tightening which distorts the top a touch so further over tightening is needed to stop rotation via the smaller contact area close to the stud which distorts the top more and so on.

My P&W model B came with a spectacularly large spanner to fit the tool post stud nut which was even more spectacularly tightened down. When you use Mr Britools big 3/4 drive torque wrench as a breaker bar to undo something its fair to call it tight! Unsurprisingly the top of the top slide was less than flat. The front of the slide was well chewed too so I built it up with weld and machined everything nice again.

Finished up by making a properly fitted full width Tee nut for the slot with position locking screws in the Tee nut. Stud screwed and loctighted into the Tee nut with a screw down ring to further hold things in position and fill the gap where the central recess of the Dickson T2 tool post lives further preventing rise. With a thin alloy shim between tool post and slide the tightening torque needed to hold the tool post stable is modest. I converted a simple tubular box spanner by cutting to an appropriate length and welding a tommy bar extending a bare hands width each side. Heaving is now verboten!



Clive

thank you clive603 i do need help at times cheers.

thought i would update you on my latest attempt.had to make a new compound cross feed screw nut with left hand internal acme thread 6 tpi.(took me all bloody day lol)the new one is on the left.

Looks pretty good to me - and if the fit on the thread is to your satisfaction then JOBSAGOODUN

As for taking all day, - how many have you made before?

only one!and that was not a real success so i just keep blundering along thinking one day i might get it right

macsonboy said:

only one!and that was not a real success so i just keep blundering along thinking one day i might get it right

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And when you were a baby, from sitting and crawling you just got right up on your feet and walked without falling over?

on another subject on ebay there is a DAREX E90 end mill sharpener for$1400.00 aus which seems high to me but do you have any thoughts on that toy?? i realize i can buy a lot of end mills etc for that money

hi just a quick update on the SB&W lathe,i know we have covered this earlier on the first set of cones but this is for the 2nd set which run directly of the motor.i was told that the cones have a convex curve to help the belt stay on and this is what i stuck with for those cones but the 2nd set is dead flat even when checked with a straight edge.now do i leave them as is ??seems a bit odd that they are already so flat makes me think that they should be this way and the first set with the curves do the job.any thoughts welcome cheers

If the other pulley has a crown and they are in perfect alignment it might work with a flat (no crown)as shown. A slight crown makes the belt want to center on the crown though and will be better in the end.