# Taper in a part



## riptide212 (Mar 2, 2017)

I have a 54 long part that needs .250 taper per foot, im,off by .031 or .007 per foot. How do fix it , do i swivel part for a total of .031 over all.

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## RJSakowski (Mar 2, 2017)

riptide212 said:


> I have a 54 long part that needs .250 taper per foot, im,off by .031 or .007 per foot. How do fix it , do i swivel part for a total of .031 over all.
> 
> Sent from my VS987 using Tapatalk



Work between centers, using a lathe dog and face plate or similar to drive the work.  Offset the tailstock by the amount of the taper in "/ft x the distance between centers in ft.  The taper is measured on one side so the diameter reduction per ft. is twice the taper.  Offset the tailstock towards the front of the lathe to have the diameter decrease towards the tailstock, vice versa if you want it to increase.


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## riptide212 (Mar 2, 2017)

RJSakowski said:


> Work between centers, using a lathe dog and face plate or similar to drive the work.  Offset the tailstock by the amount of the taper in "/ft x the distance between centers in ft.  The taper is measured on one side so the diameter reduction per ft. is twice the taper.  Offset the tailstock towards the front of the lathe to have the diameter decrease towards the tailstock, vice versa if you want it to increase.


This part is flat and must be clamped down on a horizontal mill one side is staright, other said has taper. 

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## woodchucker (Mar 2, 2017)

well now that we know you are not turning it.
Why is it variable?  have you been resetting the part on your mill ?
How long is your table on the mill?
I'll assume you have to reset your part 2 times because your table is not long enough.
I would use the slots in your table. put something that fits in the slot (just fits). use a few. use this to set the metal up against (a fence if you will. make sure you have clean burr free slots.. stone first). This is going to act to support the opposite side of the taper.  put a piece of ply on the table to be able to cut into w/o cutting into your table. Or use a piece of metal..
Lay the metal to taper so it registers at one end then put a spacer under one of the other base pieces. This is a measured piece for the distance. So if you are 24 inches from the end this would be a .50 spacer. another 24 and it would be a 1.0 spacer lock the spacers down. The lock the metal to cut down. 
One thing I failed to mention, your first support must use the corner of the block, so you can slide down and use the corner..  Or start with an offset and add that to each standoff. BTW it would be a good idea to use round standoffs (spacers) .
Now lock down the metal .. cut, move the piece down, reclamp, cut, move recut..
That's my idea, and I'm sticking to it.. BTW if the flat bar is thin and flimsy, you may want to put a backer onto it, so that the spacers register and that holds the part straight.


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## RJSakowski (Mar 2, 2017)

riptide212 said:


> This part is flat and must be clamped down on a horizontal mill one side is staright, other said has taper.
> 
> Sent from my VS987 using Tapatalk


Sorry for the misunderstanding!
I would do a sine bar type of setup with the large end on the mill table and the small end raised by 1.125" (54"/12"/ft. x .25"/ft).  If the part is too long for the mill travel, you may have to mill it piecemeal.  Set up a rigid bar in the same fashion so it tapers upward at your .250"/ft and clamp you work to the bar.  Mill as much as you can with your mill and relocate the work so you can mill the second pass.  You may have a little cleanup at the intersections but you should be able to mill the entire taper in this way.


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## riptide212 (Mar 2, 2017)

woochucker said:


> well now that we know you are not turning it.
> Why is it variable?  have you been resetting the part on your mill ?
> How long is your table on the mill?
> I'll assume you have to reset your part 2 times because your table is not long enough.
> ...


Well the bar is 2,inches thick. The table is 5 feet wide. Im rotating sides. Cutting flat side flipping over to taper side running zero from end,to end. I have about .243 per foot now. Im,clamping bar to table when,i indicate it end,to end.  So i figure if i start at center which is 27 inches and indicate .015 minus on one end it will plus to .015 on other giving me about .030 more taper over all. If that soundss right.

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## riptide212 (Mar 2, 2017)

RJSakowski said:


> Sorry for the misunderstanding!
> I would do a sine bar type of setup with the large end on the mill table and the small end raised by 1.125" (54"/12"/ft. x .25"/ft).  If the part is too long for the mill travel, you may have to mill it piecemeal.  Set up a rigid bar in the same fashion so it tapers upward at your .250"/ft and clamp you work to the bar.  Mill as much as you can with your mill and relocate the work so you can mill the second pass.  You may have a little cleanup at the intersections but you should be able to mill the entire taper in this way.


This is a large horizontal mill.using a,sine,bar wouldnt work the bar lays flat on table. With angle facing you.

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## riptide212 (Mar 2, 2017)

riptide212 said:


> This is a large horizontal mill.using a,sine,bar wouldnt work the bar lays flat on table. With angle facing you.
> 
> Sent from my VS987 using Tapatalk


Normally i would swivel table but this one doesnt work that way. So i figure just putting more angle on part would work i think.

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## woodchucker (Mar 2, 2017)

wow more info.. talk about piece meal info.. it would help to have this up front.


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## riptide212 (Mar 2, 2017)

woochucker said:


> wow more info.. talk about piece meal info.. it would help to have this up front.


Sorry my apologies.

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## riptide212 (Mar 3, 2017)

riptide212 said:


> Sorry my apologies.
> 
> Sent from my VS987 using Tapatalk


 I fixed it

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## woodchucker (Mar 3, 2017)

Glad to hear that.  How?


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## riptide212 (Mar 3, 2017)

Well i indicated straight side 0 end,to,end. Then,placed indicater on back side and in dicated for 3 feet adjusting it to .750 within 3 feet. .250 taper per foot then after that i cut the front. And taper is within .004 end to end

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## woodchucker (Mar 3, 2017)

Yep, that'd do her. Glad you got it.


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