Stuart 'No.1' : a beginners tale..

Thrown into the pot are different grades, some common ones are M2, M35 and M42, the latter two being cobalt steel, 5% and 8% respectively.

Here you go

View looking along the bar, hopefully you can see that I have cut the edge back at a radius so it does not run on teh hole below the centre line.

A view from above, the work is set to move away from the chuck eg towards the right.

Looking horizontally, you can see the slight top rake of the cutter which slopes down from the cutting edge

And an overall view, I will e-mail you a PDF of this which you can move about and zoom in on.

Jason

A big thanks for these, the diagrams are excellent and make it very clear what needs to be done. I can see the one I did needs more work. I'll carry on with that and do another from scratch as per these diagrams as well. Hope this hasn't taken you too long to do - I'll bet though that lots of others like me will learn a lot from this.. and I must say it's definitely easier to understand a little better after having a go... I'll post up my next efforts...

Allan and Bob

Thanks, some more useful info there - and I will take a look on Youtube..

Regards.

Allan.

ps. Its obvious to see the enormous amount of help I've been getting on here but what isn't obvious is how much 'off forum' help has been offered as well, the enthusiasm from others has been incredible - just totally brilliant..! Anyone starting out and thinking of joining here - don't think twice do it now!

Edited By Allan. on 17/05/2014 18:28:01

When you (not if!!) you have broken both ends of a small centre drill, remember to put it aside to make more boring cutters. It can save having to buy the HSS. Don't try to use the shank part of an ordinary drill, they are not hard.

It can be pretty fiddly setting the cutter for the correct depth of cut. If the bar is drilled at an angle you can use a micrometer or at a pinch a digital or vernier caliper across the bar and the tip. You subtract half the diameter of the bar from the reading, then double to get the diameter it will cut.

John

Thanks John

I did break one a few weeks backs now and threw it out! Hadn't thought about doing any future grinding then but will keep them in future. Yes I can see its going to be a bit fiddly adjusting the cuts but I imagine something that gets easier the more you times you do it - hope so anyway!

Just had another go at grinding again trying to get close to Jason's drawings. Its been much harder trying to get a couple of decent photo's than it was to do the grinding - and i've failed miserably, the iPhone just not focussing down that close..

Anyways here is a couple of the photos that I'm hoping will show if its useable or not. I did two but they are pretty much exactly the same.

Here is one of them..

2nd attempt at grinding the tool for the between ctrs boring bar 1.

2nd attempt at grinding the tool for the between ctrs boring bar 2.

2nd attempt at grinding the tool for the between ctrs boring bar 3.

Regards

Allan.

Just as well I poped in from the workshop.

To my eye the one you have done looks a bit pointy and if the cut surface was magnified would be very much line a fine pitch screw thread.

If you look at the second sketch I did from above you should see that the front of the tool is about 10deg from a line taken across the lathe and likewise the side of teh tool about 10deg from a line along the lathes axis. When magnified this would give the impression of a much flatter series of Vees and result in a smoother bearing.

Yoy can click all of these images to get them larger, I have added teh actual angles to this one I was just eyeballing them when I drew it so don't try to match them exactly its just to give an idea or what to aim for.

Great thanks again Jason - I'm glad you were about! Back to the grinder now for another go....

Cheers.

Allan.

"Pointy" that's easy fixed just put a radius on the end.

Bob

Yes, I would suggest just radiusing the tip by hand with an oilstone slip. If you don't have one yet, a piece of wet and dry paper glued onto a flat surface will do the trick.

John

Hi Bob and John - I don't have an oilstone yet but am going to get one. Missed your 'radius' solution before going back to the workshop - but it was good to have another play on the grinder..

Jason, if you would take another look sometime I would be grateful. No probs if its not right and I need to try again..

Its photographing this one that is the real problem for me..

3rd time lucky maybe?

3rd attempt at grinding the tool for the between cts boring bar 1

3rd attempt at grinding the tool for the between cts boring bar 2.

3rd attempt at grinding the tool for the between cts boring bar 3.

3rd attempt at grinding the tool for the between cts boring bar 4. Trying to show there is a slight top rake..

Regards

Allan.

The only thing to watch with a radiused cutter is not to go too far, it can make the width of the material being cut wider annd result in chatter, on the end of a long boring bar or middle of a slender between ctrs one it can push the tall away from the surface more than an angular one that will cut in and take a small cut. Just a few strokes is OK but don't get carried away

Great thanks a lot Jason.

For a minute back there I think I was in danger of having the only Stuart No.1 with a 'screw in' crankshaft!

I hear what you say so I'll be taking tiny cuts!

Cheers.

Allan.

Allan,

When taking close-up shots on your phone, what might work better is taking them from slightly further away and then cropping the image down to the subject. Assuming you've got some software to do it. Just an idea.

Gary

A couple of points about setting teh tool.

I theory with a 3/8" bar and the tool sticking out 1/16" it will measure 0.4375 on the mic and produce a 1/2" hole.

In practice the tip may not be exactly on the central axis, the bar may be running a fraction eccentric or have a slight bend/bow making it cut over or under the calculated size.

So take some measurements of the bore you are produceing and work out how much more the tool needs to be advanced to arrive at the desired size. Its not easy measuring a small bore so find something a bit smaller than 1/2" either the shank of a 12mm cutter or a 15/32" drill and use that as a bore gauge. A bit of maths will then tell you how much to advance the too to get to teh crankshaft size but when you get close do test fit rather than just measure.

On way to set the tool to a measurement is to have the grub screw just making the bit firm, push it out past where you want and then use the mic to gently squeeze it back into the bar, stopping when teh mic reads what you want the tool set at.

J

Hi Gary

Yes that sounds like a good idea, I'll give that a go next time, cheers - the combination of the small size and shiny steel was too much..

Hi Jason

Thats really useful thanks, I'll keep all that in mind when doing it. I've been having some 'vague' thoughts about how best to adjust the tool - the method you mention sounds perfect to try..

In a strange way I'm glad now that I've had the problems with the bearings and took the 'time out' to do the boring bar as well - If not I would have missed out on what feels to be good experiences and learning in getting or at least trying to get them back on track - finding out about between ctrs boring and laying a bit of foundation for tool grinding to build on, issues with soldering together for drilling, problems and learning about working with Gunmetal, using slot mills for making holes etc.! To have missed out on all that would have been a big loss.. Can't wait to have a go with the bar, looks like Thurs will be good as I should have a complete free day to 'play'. Tomorrow I'm going to have a go at straightening out the hole in the 'bad' bearing to get to the same size as the other one (before desoldering both of them ready for the lathe) - I'll do that with a slot or maybe try an end mill this time - on the mill again (that reminds me I need to get some 6A fuses to go back in the mill).. I thought the 'wonky' hole was at 7.5mm but checking this morning its at 9.5mm. So I'll use a 10mm cutter, very slowly and carefully which should then allow the boring bar to fit through both bearings on the lathe...

Cheers.

Allan.

Setting a boring tool is difficult,one way to get over the problem is to bore the hole as close to size as you can,then turn the shaft to suit, or bore the hole to within a few thou and finish ream to size.When restoring stationary engines I always bore the cylinders and get a new piston cast and then turn it to fit the bore.When using a between centre boring bar first check the tailstock is in line with headstock,particularly if the tailstock has been set over for taper turning at some time,The between centre boring bar has the advantage that it bores a constant diameter,though a bore may be found to be tapered this can be is due to tool wear so when taking the final couple of cuts make sure the tool is sharp. In the past when this country did proper engineering long boring bars were mainly used on horizontal borers the tools held by wedges ,screws or taper pins,and the tools adjusted by a special depth micrometer mounted on a special vee block,the vee block was held on the boring bar and the amount the tool protruded from the bar measured by the micrometer, in more recent times adjustable tool holders could be screwed into the boring bars and a index ring provided micrometer adjustment and carbide insert used for cutting,they were very good but were limited to larger bores.

Hi Nigel

Thanks for such an interesting post and some useful general methodology there. Before deciding to make one I was thinking about getting the boring bar kit from Hemingway **LINK** - it has perhaps a similar method of accurately measuring the tool adjustment as you were describing. I'm hoping to get on ok with the one I have made now though - not having made any kind of tool before it will be very satisfying if it does a good job...

Cheers.

Allan.

Allan Just a point Is your tool steel HSS or is it Silver Steel ? If silver steel you can shape it with a file and it will need tempering I personally have not seen HSS in long lengths I may be wrong

Roy

Roy its got HSS printed on the side, look at the first photo on Allans post 12.48 yesterday (wood grain background)

Its only 1/8" dia so looks about 3" long which is quite common for HSS blanks

Roy and Jason

Yes quite right it is HSS and about 3 inches long - from Tracey Tools. I didn't know there were different grades until Bob explained above, so I don't know how hard it will prove to be. I'll check the writing on it, maybe it will say which it is. The slightest touch on the smooth wheel of the Grinder was all that was needed - but then it is only 1/8 inch. I've not cut it to length yet.. Each 3 inch length was only £1 I think..

Cheers

Allan.