Taper turning with Boring Head in lathe

[Twmaster]

MB, try this:

Go to the link Dean provided.

Right click on the PDF link.

Chose 'save as' then download.

It downloaded just fine for me. I just read a handful of pages. Great stuff.

 

[1hand]

Websterz,

Thanks not too worried. Nothing else it will get me started. I'll just watch my depth cuts. I could cut off the taper, and make the attachment blogs was referring to just make the end that goes towards the boring head sorta like the way it mounts to the tail stock spindle. Clamped around the outside, instead of threaded on. It may look a bit goofy, but it won't feel alone, there will be two of us in the shop then. *bang*

Matt

 

[Metal Butcher]

MB, try this:

Go to the link Dean provided.

Right click on the PDF link.

Chose 'save as' then download.

It downloaded just fine for me. I just read a handful of pages. Great stuff.

Thanks for trying to help. I saved the file three times but it won't open. A window pops up over the fist page and when I click to send the error report the file closes on me. If I click on don't send the same thing happens. My computer guy will be around tomorrow to help me out. I did see a listing of the page amount and its in the hundreds! Or does that mean something else?

-MB

 

[Twmaster]

MB, yes the page count is ~250.

It sounds like your copy of Acrobat Reader is b0rken. Let your comp-geek tame it.

 

[1hand]

FYI................I went to Deans site and now I think I got an idea of how to turn my own dead center stub.


Thanks Dean

Matt

 

[Deanofid]

Rick, if you would like to buy one, Amazon has them. About 10 of them showing right now. Some brand new ones for $17.95. Less than the ink cartridge it would take you to print it out.

It's great to have books and manuals on your computer. I really like having certain printed references in the form of real books in my shop, though. Much more convenient than running back and forth looking stuff up on my magic box thingy.

Dean


Matt, just caught your post. Glad you found something you could use!

DW

 

[1hand]

The Machinery's Handbook Guide also has practical examples, solutions, questions to make sense of using the big Handbook.

 

[Captain Jerry]

Marv

I read this thread before I went to bed last night and all was clear. When I woke up this morning, before I even got out of bed, a thought popped into my head. It said "The workpiece is the hypotenuse. Isn't that a sine function?"

What a strange thing, the sleeping mind!

I had to check it out. At small angles, the values are verrrry close. Even so, an 8" workpiece with a 5 degree half angle, the offset difference is about .002". I don't have a boring head but isn't that within the capability of a boring head to resolve?

Jerry

 

[Metal Butcher]

Thanks for the idea Dean. The printing paper and cartridge is a big factor. I would be "borrowing" it, and that's been a no-no- in the past. Binding the whole pile of papers together is a project I wouldn't want to tackle. I would need a book to teach me how to bind, or bandages for the blisters on my hand after punching at least 750 holes!

So, I order a 'good used' one to be used in the shop environment as reference material. I will try to get a working PDF copy on the computor for casual reading and easy access to the information. I might need it for posting replies to questions posted on the forum.

-MB

 

[Maryak]

CJ,

The result is the hypotenuse, but to get there you use the vertical side of a right triangle as the centre line of the job and hence the horizontal side of this triangle is the offset, derived from the tangent of the top angle; which in turn equals half the included angle of the taper.

Hope this helps

Best Regards
Bob

 

[1hand]

Thanks blogs. As usual I jump the gun and went and bid on a MT2 boring head "1 piece of course" that will be useless to me, doing the addapter mentioned. Oh well maybe I'll get out bid. Then I'll be able to use the head I have for that's a 2 piece.

I guess for now I need to know how to fix up this sort of ball dead center, or taught how to turn the regular dead center stub.

Thanks Matt.

Somebody really wanted that boring head today.......Thank you! Now I'll get a chance to try my hand at 1 1/2 -18 treads on the lathe.

Matt

 

[Deanofid]

Now I'll get a chance to try my hand at 1 1/2 -18 treads on the lathe.
Matt

1 1/2-18? Is that a typo, Matt, or do you really have something with that thread?
Just curious.

Dean

 

[Blogwitch]

Dean,

Depending on the size of the boring head, for the 2" ones I have made before, they are about that size. It is always better to check first though.


John

 

[1hand]

You know what Dean, I've never taken the boring head off the R8 shank before. I've just been going off the ads of CDCO, and shars. They say their heads and shanks are 1 1/2 x 18. Well after reading your post I took mine apart, and low and behold...........It's not 1 1/2 x 18. I got out my gage, and it appears to be 20 tpi, and an OD of .867, so like a 7/8 x 20 sound right?

Good call Dean.

Matt

 

[1hand]

I went back through my receipts from last year to find where I got it.

http://www.littlemachineshop.com/products/product_view.php?ProductID=1266&category=1963256902

There it is in black and white 7/8 x 20

 

[Blogwitch]

I think it is all to do with who the manufacturer is Matt, they all seem to have their own ways of making things, just so that you have to buy their arbors. I definitely know mine is of the larger size.

Once I get this burner build out of the way, the first job will be making one of those clamp fittings, as it should only be a couple of hours work. Getting the slot in the clamp deep enough will be the main problem, but it should work with only a partial slot if the fitting for the nose is close enough.

Another item that I need to make is a floating reamer head for the tailstock, but I am having trouble finding free plans for that one. Anyone any ideas?


Blogs

 

[steamer]

The 1 1/2 -18 sounds right for the 3"......seems oddball, but that is what I needed for my 3" boring head......turning the thread is no worries either 1hand. 7/8-20 too.

Dave

 

[Captain Jerry]

CJ,

The result is the hypotenuse, but to get there you use the vertical side of a right triangle as the centre line of the job and hence the horizontal side of this triangle is the offset, derived from the tangent of the top angle; which in turn equals half the included angle of the taper.

Hope this helps

Best Regards
Bob

Bob

I agree, almost. The problem is that all you know is the angle and "L", the length of the workpiece. The offset is at right angle to the lathe centerline, not to the length of the workpiece. Once the offset is made, L is the hypotenuse, not the adjacent side of the resulting triangle.

See the attachment. I know its splitting hairs, but that's what we do.

Jerry

View attachment tailstock offset.cad

 

[Captain Jerry]

Sorry, I attached a proprietary file type above. Here is a PDF file

View attachment tailstock offset.pdf

 

[chipswarf]

I agree with Captain Jerry's analysis. The distance between the lathe centers decreases as the offset is increased, the constant is workpiece length, which is the hypotenuse, with center distance being the cosine side and the offset being the sine side.

With this in mind, the algebra looks like:

Let L = workpiece length and t = taper per foot or t/12 inches per inch.
The taper for the half angle is half that (taper per 'side' rather than taper per diameter), so that the half angle of the taper = arctan t/24
If we agree that this is the angle that the workpiece must make with the lathe centerline, then,

Offset = L sin (arctan t/24)

We can make this even easier by dispensing with the trig altogether. For small angles (the half angles of Morse and B&S self-holding tapers are all less than 1.5 degrees - small enough), sin angle ~ tan angle, or, equivalently, arctan number ~ arcsin number. So,

Offset = L sin (arctan t/24) ~ L sin (arcsin t/24) = Lt/24

Example:

t = 0.6 inches per foot
L = 5 inches

Using the trig explicitly, Offset = 0.12496
The simplified way has Offset = 0.12500, an 'error' of 4 one hundred thousandths of an inch.

I'm trained in math and thus can make spectacular errors. What do y'all think?

Mark

Jeez, first post. Hi, Guys!