Tapers

[d-m]

I think that this should be a vary basic procedure but I am lost. I need to turn a #3 MT and make a chuck adaptor for my rotary table. I was able to find the taper in my machinist handbook and I have a taper attachment for my lathe that I have never played with. My taper attachment is measured in 1/16Th of an inch per foot. I thought I would find a table that would guild me to the proper setting for the MT3 taper 3.875” long taper but I think I have miss the boat.
Thanks Dave
:wall:

 

[Tin Falcon]

Machinery handbook gives taper per foot as .60235 If i am looking at my math straight setting your taper attachment about half way between the 9/16 and 5/8 mark should get you ballpark then cut and measure and adjust from there.
Tin

 

[putputman]

I think mklotz has a solution on his web site for this. Maybe he will jump in and direct you to it.

 

[deverett]

To turn a morse taper, one simple way is to put a spare centre or other tool with the required morse taper on the end between centres in the lathe. The way you mount the taper will determine which way you will cut your taper. (large end or small end towards the headstock).

Set your dti exactly on centre height, adjust the taper turning attachment (TTA) as Tin suggested and wind the carriage back and forth along the full length of the floating centre. You will probably see runout on the clock as you wind. With the clock at one end of the taper, turn the TTA until you halve the error. Try again. Keep adjusting the angle on the TTA until there is no runout. It will now be set for the correct taper.

Unless you have a micrometer or vernier adjustment on your TTA, this will probably be a more accurate method than trying to set up by reading an angle on the TTA.

When you think you have completed turning the taper, wipe some Prussian blue (not too much) - or a soft lead pencil - down the length of the taper in one broad line, not all the way round. Insert your new taper lightly into the socket and rotate it. If the taper is correct, you should see an even smearing of the blue down the length of the taper. If one end of the line remains untouched, the taper is not correct. If it is only intact or smeared near the middle, it means your cutting tool is not on centre height.


Dave
The Emerald Isle

 

[d-m]

Thanks Tin, Put,& steam Dave this is a good group of folks. I will give Dave's summery a try if I can get a few hours in the shop to day. thanks again.
Dave

 

[d-m]

Hi again guys I used Dave's method of setting up my taper attachment .
so I started with a 2" round from the scrap box as I approached the 1" mark on my small end I stopped took good readings and subtracted the work reading from the finished taper in the hand book. Did the same with the large end now the way I look at it the math should be the same. it was off by .020 so I set up my indicator on the taper attachment and moved it 1/2 (.010 ) in the proper direction. then I got ascared and thought I would ask if this was the proper way to adjust the cut before i make the big mistake and it all goes down the :toilet:
Thanks Dave

 

[tel]

Not sure just how you are doing that Dave - the indicator on your workpiece won't tell you anything. You need to set the topslide angle to an existing, known good, taper with the indicator, then change the indicator for a tool, the taper for your workpiece, and have at it.

Here, I am setting up for an internal taper (socket) for an external you will want the taper mounted the other way around.

 

[deverett]

Tel

He is using a taper turning attachment.

That means (to me) he should be running the carriage up and down his test taper, with the TTA engaged, not the topslide. The adjustment should be to the angle on his TTA not the topslide.

Or have I got this completely wrong? Not unusual, I know!

Dave. Remember to disengage the leadscrew from your cross slide before using the TTA.

Dave
The Emerald Isle

 

[Maryak]

Dave. Remember to disengage the leadscrew from your cross slide before using the TTA.

Dave,
Another thing to dismantle. :

That's why with all the messing around TTA's are IMHO a PITA, unless of course you have a very long taper, or a taper thread to make and then they come into their own.

Good Luck and don't let the job taper off. ;D

Best Regards
Bob

 

[tel]

Tel

He is using a taper turning attachment.

That means (to me) he should be running the carriage up and down his test taper, with the TTA engaged, not the topslide. The adjustment should be to the angle on his TTA not the topslide.

Or have I got this completely wrong? Not unusual, I know!

Dave. Remember to disengage the leadscrew from your cross slide before using the TTA.

Dave
The Emerald Isle

Oops! My bad! :-[

The proceedure is the same tho - set the bar on the tta with the indicator running on a true taper set up as above.

I'm with you tho' Bob, I have a tta on the Myford, but only use it as a last resort.

 

[deverett]

I started making Chris Heapy's design of TTA for the Myford. I realised quite soon after starting it that I would probably never use it, preferring like Tel and Bob to use the topslide, which is quite long enough for any taper I am likely to turn.

So it lies unloved, 75% finished under the workbench. There are plenty of other things that are higher on the list of priorities in my very limited time in the 'shop.

Dave
The Emerald Isle

 

[Maryak]

Guys,

My preferred method is to offset the tailstock as you can continue to use the auto feed. John Stevenson and others have posted some great info on using the boring head on the tailstock to offset for the larger tapers but I can't find the link.

Best Regards
Bob

 

[John S]

Setting a taper for thickies part 1

Sorry no pics so I'll do my best to describe it.

First get a parallel bar and put between centres or in a chuck and support on a centre in the tailstock.
Set the top slide to zero and lock it. Then using a piece of square bar or shank of a lathe tool set it up sticking out like a boring bar, wind in so the bar touches the parallel bar all along it's length.
Adjust by moving the square bar in to tool post or rotating the tool post.

All you are doing at this point is getting the square setting bar parallel to the parallel bar in the chuck, once this is done do not touch the toolpost or square bar.

Now replace the parallel bar with your master taper, old drill, chuck arbor etc and again support with a centre.

Now slack the top slide off and wind the setting bar in using the cross slide and as it makes contact with the taper it will spin round, nip the top slide and check using the MKI eyeball and a sheet of white paper underneath that it contacts over the whole length, then tighten to top slide.

The top slide is now set to the exact angle required. You don't need any tables, hell you don't even need to know the angle, no dial gauges - nothing but a sheet of paper and an eyeball.

Try it and see, takes longer to write about it than do it and once you have done it that experience is there for life.

John S.

 

[d-m]

well again an overwhelming response and thanks to everyone. I am going to keep on the path i am going I seem to be Farly close using my taper attachment. As my post pointed out I was 0.020 (I think I miss typed there) from being with in tolerances. I am heading to the shop now to take some cuts and measurements and see if I will hit my mark .
Dave

 

[d-m]

Well project taper was a flop but not a total loss. I was just starting on the plug end that would fit in the threaded adaptor for the chuck when all of a sudden and with out warning it came out of the chuck got caught between jaws and was bent. On the bright side I learned that with a little carfull set up a taper attachment will do a good job.
And I also realized sitting on my stool thinking of all the other things that could have been done in the 3+ hours of working on this that there was an easier way to mount my chuck on my rotary table. I will see if I can get that done next weekend today was work on the Austin Mini day Ill be glad when that's done and I have more time to play as my wife likes to call it.
Dave

 

[tel]

Try it and see, takes longer to write about it than do it and once you have done it that experience is there for life.

John S.

I'm gonna try that the very next time I have a taper to do.

 

[SignalFailure]

I use a similar method for centering rectangular section stock in the 4-jaw and it seems to work a treat:

Put a nicely faced square bar in the tool post and feed it up to the work
When touching, move saddle to right (out of the way), flip the chuck 180 deg and move the saddle back.
Adjust jaws so the toolpost bar just slides along each side
Repeat for opposite pair of sides.

I reckon it's as good a way as any....