Few people know the difference
between Dowel Pin Reamers and Standard Chucking Reamers.
Whereas Standard Chucking Reamers are produced with little
back taper and a plus diameter tolerance, Dowel Pin Reamers
are produced with increased back taper and a minus diameter
tolerance.
(This specification is as suggested by Danly Machine -
Chicago, Illinois.)
Yankee Dowel Pin Reamers are produced to Danly's recommended
specification with the added feature of precision ground
flutes.
To gain maximum results in dowel
pin installations, the following is recommended.
-
Drill holes 1/64 under dowel pin
size either in cast iron or steel when below 1/2 diameter.
For holes 1/2 and over in size, the drill hole may
be 1/32 under the dowel pin size.
-
Ream holes in cast iron .0005 undersize.
For example, for 1/4 dowel, use a .2495 reamer to
obtain a press fit. For tool steel which is to be
hardened, use a standard size reamer. The shrinkage
in hardening will take care of a press fit. Scale
should be removed by polishing or lapping.
How to Dowel Very High Grade Tools
or Dies.
-
Drill holes in tool 1/64 undersize
when below 1/2 diameter. For holes 1/2 and over, drill
1/32 under dowel size.
-
Ream holes .0020 undersize.
-
Ream holes .0005 undersize. (Note:
Tolerance of reamer is + .0000 - .0002 with .0050
back taper per 1-1/2 length. Grind for end cutting
with no relief on periphery.
-
Harden tool steel and lap holes to
fit reamer.
-
Align and secure tool steel in place
on its mounting block or base. Use lapped holes as
a jig and follow same drill and reamer sequence as
above in Steps 1, 2, and 3.
Part number = Series and Diameter
Size
example Series 1475 Right Hand Spiral Cobalt Dowel Pin Reamer
.1875
Part Number = 1475-.1875 |
