# Anyone know how to make tappered Mandrels?



## COMachinist (Apr 16, 2014)

Hi All I need to make some tapered mandrels to turn some spacers with. I need to know what the tapper angle and the tolerance is for each mandrel for particular size. I plan to make them out of some 4130 and heat treat them, to keep and use again. I have a heat treat furnace PID controlled. I plan to have them ground by a friend after heat treat. Any help?
Thanks
CH


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## 12bolts (Apr 16, 2014)

More info needed. Is the taper to suit a morse #, (or other), in a spindle? Or is the part you are holding tapered in its bore?

cheers Phil


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## rgray (Apr 16, 2014)

You need tapered....or expanding. If you're making bushings or spacers with straight inside dimensions then expanding may be the way to go.


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## LEEQ (Apr 17, 2014)

Any slight taper that suits you. As to hardening, often mandrels are a bit sacrificial in that they get cut into a bit. You would trash the grind on your bit if you accidently ran it into a hardened shaft. Perhaps a run out groove like you would use in threading would be a good feature.


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## GK1918 (Apr 17, 2014)

Lets see CH,  I'll see if I'm on the same page.  This is something we do here (too many times) usually for 'one offs'.  No need for heat
treating.  With a pile of junk stock which is "sacred",  we try for a .002 taper and use the press.  I want the mandrel to be sacrificial, not
the part.  I'm talking about turning or threading between centers.  If I am comming through, a part with a 1/2 hole, a shaft for a short
distance is turned .002 over size then we turn that to a taper back to .500 and press it.  I advise using alum for the mandrel, because
we are not about to hog cuts like .500;  we are only dealing with light cuts and alum will not damage the part.  Then after, its put back
in the stock pile.  In fact I'm am doing so this week with a new improved engine cam bearing remover and installer that I plan to machine for
Napa for resale.  And those go for $100+ I can for $50  Our old school local mom & pop Napa allows this.  So try and keep no more than
.002 or .0015-6-7 or so...over a snug fit...




"turning between centers rules"


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## COMachinist (Apr 17, 2014)

12bolts said:


> More info needed. Is the taper to suit a morse #, (or other), in a spindle? Or is the part you are holding tapered in its bore?cheers Phil


No not MT I need to turn some bushings on center. Lathe tapered turning mandrels. I have a few expandable mandrels but they are not the right size and figured while I was making one may as make a useable set. I found some info of .0005 per inch which is .006 per foot. That don't sound right to me? Seams like a lot of tapper.ThanksCH


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## COMachinist (Apr 17, 2014)

GK1918 said:


> Lets see CH,  I'll see if I'm on the same page.  This is something we do here (too many times) usually for 'one offs'.  No need for heattreating.  With a pile of junk stock which is "sacred",  we try for a .002 taper and use the press.  I want the mandrel to be sacrificial, notthe part.  I'm talking about turning or threading between centers.  If I am comming through, a part with a 1/2 hole, a shaft for a shortdistance is turned .002 over size then we turn that to a taper back to .500 and press it.  I advise using alum for the mandrel, becausewe are not about to hog cuts like .500;  we are only dealing with light cuts and alum will not damage the part.  Then after, its put backin the stock pile.  In fact I'm am doing so this week with a new improved engine cam bearing remover and installer that I plan to machine forNapa for resale.  And those go for $100+ I can for $50  Our old school local mom & pop Napa allows this.  So try and keep no more than.002 or .0015-6-7 or so...over a snug fit..."turning between centers rules"


Yep we on the same page . I thought I would make them out of the 4130 because I have a bunch of drops about 6-10" long and in almost every size up to 1.5" I can see you would want the mandrel softer than the parts. But mine are mild steel and I make these from time to time for my old Ford 9n tractor. So that is why I said heat treat for repeated use. Plus setting up the taper jig is a pain if you know what I mean.  Now is the .002 tapper/foot or is that/inch. Do you have problems with steel on Alum mandrels galling? Do have a drawing of the mandrels just to make sure I have this right?ThanksCH


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## GK1918 (Apr 17, 2014)

COMachinist said:


> Yep we on the same page . I thought I would make them out of the 4130 because I have a bunch of drops about 6-10" long and in almost every size up to 1.5" I can see you would want the mandrel softer than the parts. But mine are mild steel and I make these from time to time for my old Ford 9n tractor. So that is why I said heat treat for repeated use. Plus setting up the taper jig is a pain if you know what I mean.  Now is the .002 tapper/foot or is that/inch. Do you have problems with steel on Alum mandrels galling? Do have a drawing of the mandrels just to make sure I have this right?ThanksCH



Woh woh CH,  Ford 9N  what are you up to.  we are maybe only ones that specialize with Model T's up to 1953 atleast around here. 
exactly what are you doing?  the taper is by the inch. No I dont have prints.  I say use alum and press it cause alum will not hurt
the part. We have three 8BA V8s to machine (same as a 9-2-8 N Ford.  As far a repeated use, just use longer stock for a mandrel so you
get more mileage the reuse it again.  You say taper jig?   no we taper with the compound on a lathe. Some where I just wrote about
(i got brain dead) a new and improved cam bearing removal and installation tool just for these flathead Ford 4 & V8 engines.
galling?  no its pressed in pretty good for turning between centers.    reply back I just may have what you need.
"flatheads forever"  This V8 is perfectly standard no cracks amazing next machine valve seats 4 cyl Ford
this is a late EAB (8BA) one half of a Ford tractor

sam


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## COMachinist (Apr 17, 2014)

LOL yep gota love these old iron tractor and machines. I have had the 9N for 20 years or more rebuilt just about every thing on it, still rebuilding stuff on it).
mine has a 50" Big R bushhog on it, does real well too.
Thanks Every one for the input.
CH


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