Boring Bar Setting Device - for between centres

[raynerd]

I posted after Christmas about how to go about boring for my Webster engine in a which a few of you suggested boring between centres.

http://madmodder.net/index.php?topic=4093.0

Although I was very near to making a standard boring bar and having a go with that, I decided that I would like to attempt to between centres as it is something I`ve not done before. Rob Wilson posted regarding making a device to measure the distance or reach of the boring bar which in my opinion was an excellent method to accurately measure this. He kindly helped me with plans for this device so I went ahead and built one... cheers Rob 

A piece of scrap ally I rescued months ago!

The main 2 pieces cut to shape with the guide rods. I deviated from the plans here which stated to bore 1/4" and loctite the guide rods into the top T shaped piece. I didn`t fancy that, so I decided to only drill 2/3 of the way through the top piece and thread the top of the guide and screw it in position. Will probably use some thread lock on final assembly. I`m pleased with this, it looks tidy (not drilled through) and certainly solid. It also can be disassembled should it need to be.




This sort of shows how it will work. The two V slots will clamp down onto the boring bar with them bolted together using the guide bars. I now need to make a plate on the top which will hold a DTI and a plate on the bottom which will hold the adjusting screw.


I finally completed the boring bar setting device after many more hours than expected.

Here are all the parts required. I have used stock M3 screws for the supporting brackets and a stock M4 screw for the grub screw to hold the dial in place.


The plans also required that a flat button is made for the DTI in use so that you can measure the maximum projection of the boring bar


Initial mock setup on a piece of ally bar. I`ll be using a steel bar for the boring bar when I get around to cutting it. It works by turning the screw at the bottom which will push the tool steel through the boring bar and the DTI will measure the distance and therefore the bore radius.


And a final assembly


I guess the next step is using it but I need to figure out how to mount my work to the saddle.

[Trion]

Looking good! Another one I need to make some day 

[Rob.Wilson]

Hi Chris


Great job  

Just a couple of things to watch out for when using the tool ,,, are when you position the DTI plunger over the cutter , lightly clamp the setting tool to the boring bar then  rotate the setting tool  to the position were you get the greatest reading on the DTI  then zero the dial and lock the tool in position .

Secondly dont be tempted to remove the boring bar from the lathe to slide of the setting tool off the boring bar , because when you put the boring bar back you may not apply the same tail stock pressure ,,, the pressure from the tail stock dose bend smaller dia boring bars a few thou ,, witch dose increase the radius of the cutter .  i normally slide mine over the tail stock barrel to save unscrewing  the setting tool completely .


Rob      

[raynerd]

Cheers Rob for the advice. I`m just totally stuck now how to mount my work onto the saddle without having any T-slots. I know JasonB on the other thread showed how he bolted his wooden block down onto the cross slide.

The only thing I can think of is if I remove the cross slide and drill and tap it at the 4 corners. I could then make an aluminium plate with some T slots in it or even just with some thread holes for fixing points for now (I`ve not got a T-slot cutter - I could slot it later). I could then mount the plate onto the saddle when needed. For this job I don`t need T slots but for it would be useful in future.

I don`t know if this would work and would 4 threaded holes bolt the plate down securely enough?

[raynerd]

I know you all know what a saddle looks like but this is my idea. If I take off the compound slide and then fit a plate along the cross slide as shown by my "painted" image!

[madjackghengis]

Hi Chris, from the looks of it, you are working on a South Bend or something very close to it.  I had a similar choice with my ten inch Logan, when I started getting my shop together and was using a small drill press for a mill, and my cross slide equally devoid of any means of clamping to it.  I bought a casting from Metal Lathe Accessories, a casting for an "Atlas style cross slide" which has T slots and holes for mounting, and was about to machine the casting entirely on my lathe, clamping with C clamps to the tool post and to a couple angle plates I machined on my face plate to get square.  I no longer use the original cross slide at all, as the atlas style is far more useful and convenient, and I've put an atlas top slide on it as well, as I like it better than the original set up.  At worst, you can put oak blocks across the "wings" of your carriage, and if you're lucky there are some holes in those wings you can bolt to, and basically wedge everything into place that way, but that definitely is the most accurate way to get a straight bore that is as close to round as can be got, with a bar between centers.  I would do almost anything to avoid drilling holes in way surfaces, they tend to gather swarf, and will throw off the accuracy at the worst of times.  An old cast iron weight plate from a weight machine is a good blank for a cross slide, and can fairly easily be machined on the lathe its self.  I used a five inch face plate, two pieces of inch and a half by 1/8th angle iron to hold a quarter inch cutter with a carbide brazed tip, with the angle iron drilled to fit on the face plate, and drilled to clamp together and hold the cutter bit as a fly cutter.  I machined two different cross slides and a three by three by eight box box type angle block, all using the original cross slide, cobled together with hold downs and clamps, I just had to take it slow, and measure very carefully.  I think you've got more flat cross slide under your top slide than I have, so you should have enough at least to start with.  Try it out with a piece of scrap, and if it has problems, the scrap will guide you to a stout set up, and you'll get your accurate bore. mad jack

[raynerd]

Thanks Madjack for the reply. I`m reluctant to machine a cross slide. I didn`t really fancy machining a new top slide, it seems a big expense that I can`t really afford and I`m worried I`d muck it up. To buy one ready made for my Boxford is £140 which I definately can`t afford at present.

http://www.rdgtools.co.uk/acatalog/Boxford_Replacement_Parts.html

The only other option is to use the tapped holes that are already in the top slide. If you looks within the red lines, in the centre there is a hole at the front and then also another tapped hole at the back of the toolpost. I don`t know what they were used for, they were there when I purchased the lathe. Would these two holes be enough to fasten my wooden support down? Or even a metal support like I suggested - I doubt it.
Madjack, I do understand what you mean about it not being a good idea to drill and tap any part of my saddle. I just thought it was a good way of mounting a mounting plate on should I need it.

I`ll have to take a look at my lathe to understand what you mean by "At worst, you can put oak blocks across the "wings" of your carriage, and if you're lucky there are some holes in those wings you can bolt to, and basically wedge everything into place that way,""  That might by the way forward for now.... a T-slotted cross slide will definately have to wait a while due to costs...but I want to bore asap so I`ll have the keep thinking and looking. Thanks again. Anyone else any thoughts?

Chris

[raynerd]

Just been on the Boxford user groups and some interesting info on there. Apparently Boxford make a boring table:





The bottom is the same round dove tailed attachment that the compound slide uses:





If I could some how put this spigot on the bottom of a plate, I could then swap it for my compound slide when needed and use when needed , obviously the plate could be tapped or/and T-slotted.





So this will be my setup, but on the plate obviously.


Any thoughts or ideas on this one?

[ieezitin]

Craynerd

I had your particular problem for a long time of not having a T-Slot assembly, and my milling capabilities are limited too so I just one day took the time to manufacture a base plate that sits on the cross slide and I found a decent cast iron angle plate at a auction. I have not regretted it either, I have use it multiple times and I gained my time investment back in a flash.
I think the road you are travelling is the correct one, purpose tooling cost money but time is what your flush with so spend that, like i previously said this would be a mod that will pay dividends.

Nice job on the indicator bracket. I am finding this thread very interesting.

Thanks.    Anthony.

[Rob.Wilson]

Hi Chris

Thats the way to go     ,,,,,,, you could just turn up a tapered  spigot and screw it to your plate 


Looks like i will have to make one of those boring tables for my boxford 

Rob

[Dean W]

Good job on the tool setter, Chris.  Looks nice, and it will surly be useful!
You're putting a lot of good ideas to use for getting your engine built.  Keep at it.

Dean

[kellswaterri]

I posted after Christmas about how to go about boring for my Webster engine in a which a few of you suggested boring between centres.

http://madmodder.net/index.php?topic=4093.0

Although I was very near to making a standard boring bar and having a go with that, I decided that I would like to attempt to between centres as it is something I`ve not done before. Rob Wilson posted regarding making a device to measure the distance or reach of the boring bar which in my opinion was an excellent method to accurately measure this. He kindly helped me with plans for this device so I went ahead and built one... cheers Rob 

A piece of scrap ally I rescued months ago!

The main 2 pieces cut to shape with the guide rods. I deviated from the plans here which stated to bore 1/4" and loctite the guide rods into the top T shaped piece. I didn`t fancy that, so I decided to only drill 2/3 of the way through the top piece and thread the top of the guide and screw it in position. Will probably use some thread lock on final assembly. I`m pleased with this, it looks tidy (not drilled through) and certainly solid. It also can be disassembled should it need to be.




This sort of shows how it will work. The two V slots will clamp down onto the boring bar with them bolted together using the guide bars. I now need to make a plate on the top which will hold a DTI and a plate on the bottom which will hold the adjusting screw.


I finally completed the boring bar setting device after many more hours than expected.

Here are all the parts required. I have used stock M3 screws for the supporting brackets and a stock M4 screw for the grub screw to hold the dial in place.


The plans also required that a flat button is made for the DTI in use so that you can measure the maximum projection of the boring bar


Initial mock setup on a piece of ally bar. I`ll be using a steel bar for the boring bar when I get around to cutting it. It works by turning the screw at the bottom which will push the tool steel through the boring bar and the DTI will measure the distance and therefore the bore radius.


And a final assembly


I guess the next step is using it but I need to figure out how to mount my work to the saddle.

   

Hi folks...spotted  the posts for the between centres boring bar just what i need... i am now in the process of making one after trying
ordinary boring bar ...too much vibration...then set up for a boring head cut away merrily until it reached where the vibration started
then the cutter jammed ......obviously some discussion was needed with a proper machinist... we both agreed that there was a hard
spot in the core centre...this would best be tackled with a between centres boring bar with the job set up true to the bar
he reckoned that it should cut a clean path...i tkink the between centres set upis the strongest set up of all in this case...
all the best folks,
            kellswaterri...John,

[vtsteam]

Thanks for resurrecting that thread, kells, I hadn't seen it before.

[Fergus OMore]

Really, it is all a lot of fuss for not a lot.

I made up a pair of inline boring bars to 'do the bores' on a Quorn. One was for a notional 1.25 whilst the other ( which I still have) was for the precise 1" and then 1.003".  Provided one puts a controlled advance of the bit- say 1/4" x 40TPI and the right angle to control the advance- that is it. Mine came from the words and music of George Thomas in Model Engineers Workshop Manual.

In all of this, one bores TWO castings- with four holes- each pair parallel to one another.

Surprisingly, it is a lot simpler than having to make a boring bar anyway and then an expensive Gizinta and then a bracket. Pretty, but well?

Norman

[vtsteam]

Norman, alternatives to the way you do things are just a fact of life. It's not necessary to put them down. You're welcome to show and explain useful alternatives yourself which would be great, and probably useful to others. But cut the cryptic swipes, please.

[Fergus OMore]

Not intended as a cryptic swipe, merely a possibly easier way.

My apologies if that is the way that it appeared.

Norman