Headstock Shelf for Powermatic 3520C Lathe
I added a shelf to the Headstock of my new Powermatic 3520C lathe. See
photo.
All of my lathes have a shelf on top of the headstock. I have found
that it makes a great place to store live centers, chucks, etc. Everything
is very "handy". My students and friends quickly fall in love my
headstock shelves.
My old PM 3520B lathe had what I am calling a "1st
generation" shelf. It was just one level. My Oneway lathes have
"2nd generation" shelves. They are 2 levels. My new PM3520C has a
new "3rd generation" shelf design that incorporates everything I
have learned over time. I really like it! It is 3 levels.
Note: For more info on my new lathe see "My New Powermatic
3520C Lathe Verses My Old Powermatic 3520B Lathe" blog entry.
Here is a close up view of the new headstock shelf on my PM 3520C lathe. It
is a 3 level design.
Click on photos for a better view.
Overall the shelf is 18" wide by 15-1/2" deep. See latter
photos for more details.
Here is a close up of the headstock shelf on my OLD PM 3520B lathe. It was
a 1 level design. The shelf was 16" wide by 16" deep.
I used this design for a long time. But it was a bit of a pain.
Because, I had to store my frequently used live centers at the back.
Reaching over things in the front to get the centers in back often sucked.
Live centers, etc had to go on the back because "the
headstock" and the VFD (controller box) on the back of the headstock
blocked most of the space under the plywood. I could only drill holes for
things that stuck down below the plywood at the back of the 1 level shelf.
For a better explanation see "Side View from Spindle End" photo
below.
Storing any tool rests on this shelf DID NOT work. The long
projections on the tool rests blocked or interfered with any thing else on
the shelf.
Here is a close up of the headstock shelf on one of my Oneway 2436 lathes.
It is a 2 level design.
This shelf has to be a lot narrower. So, it does NOT block turning
on the outboard side. The shelf is 10" wide by 14" deep.
I like the 2nd level on this design. It allows EASY access to the
tool rests. The 2nd level is tall enough so I DO NOT bang my hangs into any
points on live centers, etc on 1st level.
However, this design is still a little bit of a pain. Because, I
have to reach over things in front to get to frequently used live centers
in the back.
Note: The 2nd level is 10" wide by 2-3/4" wide and the
plywood supports are 4" tall. The shelf is elevated 1.5" above
the headstock by two 3/4" plywood spacers visible in photo. See "Aluminum Shelf Support on Oneway Shelf" photo at end for more
details.
Now I am going back to the 3rd generation shelf on my new PM 3520C lathe.
Here is a photo from a higher up angle, so you can see everything.
Overall the shelf is 18" wide by 15-1/2" deep.
A place for everything and everything in its place.
Any shelf on the headstock of a lathe needs to built like a tank!
It MUST be able to take any "rock rattle and roll" the lathe may
be forced to endure when a rough or out of balance piece is mounted on the
lathe. The shelf should not move around for any reason! Everything on the
self must be secure. Anything that rattles even just a little during normal
lathe operation can drive you crazy.
I am NOT going supply any plans or step by step photos. So here are some
dimensions for anyone who wants to build their own.
Level 1 and Level 2 are 18" wide by 8" deep. Note: They
overlap by a 1/2" due to tongue and groove construction. See latter
photos.
Level 3 (the top) is 18" wide by 2-1/2" deep. It is
supported by plywood spacers that are 2" wide by 3-1/2" tall.
The plywood back is 14" wide by 12-1/4" tall. The cutout
on the left for hand wheel clearance is 7" wide by 8" tall. See
latter photos.
It is 1-3/4" from the top of the Level 1 plywood to the bottom
of the Level 2 plywood. i.e. the location of the dado cut in plywood back
is 2" down from the top. 1/4" of the back at top is buried in a
1/4" deep dado on the bottom of Level 2. All dados are 1/4" deep.
I like everything in my studio to look nice. Thus I use reasonably
good plywood and finish everything with 2 coats of Watco Golden Oak Danish
Oil followed by 2 coats of Miniwax Semi Gloss Wipe On Poly.
I use good quality 3/4" 7 layer plywood from local Home Depot.
ACX grade. They don't label it, but I think it is southern yellow pine.
Around $38 per sheet. It comes and goes. When it comes, I stock up. There
is no way I would use EXPENSIVE Birch, Maple, Oak, etc plywood because the
outside veneer layers on expensive plywood is like paper thin and the stuff
inside is often crap with voids. I like the outside layer of my plywood to
be the same thickness as all the inside layers (roughly 1/16") so I
don't end up with crap if I accidentally sand thru it or when I round
the corners over. "Sanded Plywood" is ok. However,
"Sande" plywood is to soft. It's crap.
I belt sand the exposed edges on all of my plywood to remove all
open grain. i.e. to make them look better. I sand the flat surfaces to 220
grit with a random orbit sander and then I round the edges over with a
random orbit sander. The sander creates less tear out then a router when
rounding over.
If you just drive a screw into the end grain of plywood you will
just split the plywood. There is no strength. To avoid this problem I
capture all of my joints in dados. I glue the joint with yellow carpenters
glue and screw the join with 2-1/2" decking screws. The long screw
contacts more surface area. Short screws just pull out of the end grain on
plywood.
My favorite band of screws is Scorpion. I ONLY use there ceramic
coated decking screws. They are hi thread, square drive. You can NOT get
these at Home Depot, or Lowe's. You have to go to a real hardware
store. However, any good quality decking screws will do the job.
Note: It appears that the "Golden Oak" colored Watco
Danish Oil is no longer available. This is a real shame. Because it is my
favorite. It works real good on things with lots of holes. It is thin, you
can just pour it on. It gets in all the holes on it's own. You
don't have to work at it. I work over an old cafeteria tray. The tray
collects the excess when I pour the oil on. When I am done, I just pour the
excess back in the can and use it in the future.
The Level 1 plywood goes over the headstock. I then routed out the plywood
to accept the stock PM rubber mat that goes on top of the headstock.
I store my chucks, live center cones, etc on Level 1. This is
dictated by a no thru holes in Level 1 requirement.
On the right, the top of Level 1 bolts to the top of the cast iron
lathe headstock. Thus on thru holes are possible. On the left there are no
thru holes for safety! I don't want my hand to "catch" on
anything hanging down when I use the hand wheel.
The left side of Level 1 can take a lot of weight. It is NOT just
cantilevered out there! It is firmly supported by plywood at the back that
supports Level 2 and extends down the back of the headstock. See "Support Over Hand Wheel" photo below.
Note: If you look in the bottom left corner of photo you can see
the motor on the lathe. The 18" wide shelf is narrower than the motor.
Latter you will see that the Level 2 part overhangs the VFD (big black
control box) on the back of the lathe. Thus the shelf DOES NOT add to the
overall footprint of the lathe!
Level 2 (Middle Level) and Level 3 (Top Level)
I like lots of holes in Level 2. You can never have to many holes. I can
never understand why people make things with just a couple of holes.
In my 3rd Generation design I created the 2nd level and elevated it
by 2-1/2" so I can have holes over the VFD. Something like a #2 MT
live center sticking down thru a hole in the Level 2 plywood does NOT hit
the top of the VFD on back of headstock. In my 1st Generation design, no
holes were possible over the VFD.
The holes vary in size. So small things do NOT fall thru the holes.
All of the big holes in Level 2 and Level 3 are 1-1/8" diameter. This
works good for tool rests, and most #2 MT things. Because most #2 MT things
have a head on them that is bigger than 1-1/8". I drill a few
11/16" holes for #2 MT things with a small head. I drill lots of holes
that will accept the "Red Bar" Oneway ships with it's face
plates, etc. I find that size holes works good for lots of things. Then
some smaller 3/16" holes for Oneway Live Center knock out bar, etc.
The line of small holes at the front of Level 2 go down into the
plywood back. Most of them are not very deep.
I drill the big holes with Forstner bits to minimize tear out and
then round over the edges using a 3/16" round over router bit. I drill
the smaller holes with brad point bits and then round over the edges using
a SINGLE flute counter sink.
The big holes in Level 3 line up with the Level 2 holes. So long
tool posts, etc just go thru both levels. I clamp Level 3 to Level 2 and
then drill the hole all the way thru.
The 3 wooden knobs sticking up help me secure things on the left side of
Level 1. They are slighly smaller than the 1-1/4" spindle threads on
the lathe. There are 3 more knobs on the left under UHMW codes and Colet
Chunk. Then another one under the big chuck. The knobs keep things from
shifting around when the lathe "rocks rattles and rolls".
In my old 1st Generation design, I drilled show big shallow holes
for the chuck. See "1st Generation Shelf" photo above. That did
not work out well. The knobs are a better solution.
I turned the knobs with 3/4" tenons on the bottoms that fit
into 3/4" non thru holes in plywood.
Just to right of the Oneway chuck is the wrench for the chuck.
Pointed to by blue arrow in photo. I REALLY like having the wrench sticking
up like this rather than going thru a hole. If it goes thru a hole then the
bar on the end of the wrench takes up to much space and fouls things up.
When the wrench sticks up like this, it is easy to find and use.
The thing the chuck wrench fits into is 1-1/2" in diameter
hard maple with a 3/4" tenon on the bottom to fit into plywood. The
tenon has a 5/16" thru hole so any saw dust drops thru rather than
clogging things up. The top is drilled and hollowed with a spindle gouge
until the wrench fits in there like a glove.
I drilled holes for special things behind the mat on the right side of
Level 1. Things, I don't want to lose because they cost to much to
replace. I size the holes to be just right. Pointed to by green arrow in
photo.
From left to right. The Slide Off pin from Tailstock end of PM
lathe in a nut. The Oneway Chuck screw. Center point from Oneway Live
Center, Knock out bar for Oneway Live Center. The red thing is a neat
little Allen wrench from Trent Bosch.
Level 1 – Powermatic Mat Removed
This photo shows what is under the PM Mat that comes with the lathe. I
routed out the plywood to allow the mat to sit there nicely. It needs to be
deep around the outside and shallow in the middle to support the mat. In
the front it needs to drop down a bit to match the mat.
The 2 silver flat head screws pointed to by blue arrow in photo,
are really the top of 5/16" flat head bolts that I use to attach the
shelf to top of headstock. I drill thru the plywood to line things up. Then
remove the plywood and tap 5/16" x 18 holes.
Note: The headstock shelf is also supported by a piece of plywood
bolted to the back of the headstock. See "Support Over Hand
Wheel" photo below.
The plywood spacers between Level 2 and Level 3 are 2" wide by
3-1/2" tall. Each spacer has two 3/8" diameter holes that go all
the way thru from top to bottom. I drilled them on my drill press.
I temp screwed Level 2 to Level 3 (with out the spacers). First I
drilled counter sink holes in the top of Level 3 for 5/16" diameter
FLAT head bolts with a SINGLE flute countersink. Then I drilled 5/16"
diameter holes all the way thru both levels.
After stain and poly, I used 5 min epoxy and 6" long
5/16" flat head bolts to attach Level 3 to Level 2. I then cut off the
excess bolt length. The 3/8" thru holes in spacers gave me enough
wiggle room to line things up. The epoxy eliminated the wiggle after it was
dry. I epoxied the nuts on because they came lose on my Oneway lathes. See "The Back" photo below for nuts on bottom of bolts.
This photo also gives you a better view of the thru holes from
Level 2 to Level 3. The long tool post on the Steve Sinner tool rest goes
thru both levels. The bluish grey tool rest. Steve makes his tool posts
long so they work with stock PM banjo.
I elevated Level 2 to make it easier to see and access things that were
behind things on Level 1
This photo also shows another reason why I elevated Level 2 on my
3rd Generation design. Because, I wanted Live Centers, etc stored in the
Level 2 holes to clear the VFD on back of lathe. Note: The VFD is inside of
the big black box on the back of the lathe.
Zoom In Side View from Spindle End
The green arrow in photo points to a 1/4" deep dado in the back plywood that captures the Level 1 plywood. This allows me to screw the back plywood to Level 1 with out splitting it.
Zoom In Side View from Hand Wheel End
Another photo for people who want to make something similar.
Note: The photo was taken from a perspective that makes it appear
things are not square and/or level. Everything is square and level in the
real world.
The blue arrow in photo points to the plywood on the back that really
supports everything. Level 1 and Level 2 are NOT just cantilevered out
there.
There is NO WAY I want to bang or catch my hand on anything when I
use the hand wheel. Thus nothing hangs down from above into this space. The
plywood on the back is cut out to create a nice big clearance space and all
the corners are rounded over. The cutout in back plywood for hand wheel
clearance is 7" wide by 8" tall.
The green arrow in photo points to a 1/4" deep dado in the
back plywood that captures the Level 1 plywood.
See photos below for more plywood on the back shots.
The red arrow in photo points to the plywood that goes down the back of
headstock. It really supports everything.
I removed the VFD (the black box on the back of the headstock) and
installed the plywood using the VFD threaded mounting holes on the back of
the headstock. To do this, you have to removed the back cover from VFD.
Then reach in there with an Allen wrench to remove the cap head screws (aka
bolts) that attach the black cover to headstock. I replaced the cap head
screws with longer ones. Long enough to go thru 3/4" plywood. I
drilled holes in the plywood that matched holes in black VFD cover. Then
bolted everything back together thru the VFD cover. Not easy. I also had to
remove and reinstall the ground wire connection to headstock. This was a
pain. I had to drill a 1" hole in plywood to clear the ground wire and
screw. I did NOT remove any of the wires from the VFD. I just worked around
them. Not easy, but doable.
The back of the headstock is slanted inward. Thus, there is a space
between the plywood and headstock. See green arrow in photo. This space is
there because the VFD mounting holes go into cast iron stand offs on the
back of the cast iron headstock.
Note: I known some people are not going to like dorking around with
the VFD. It was my last resort. On my old PM 3520B lathe the back of the
headstock was wider. Thus I got away with mounting the plywood on the back
by just running it next to VFD. This was not possible on new PM 3520C lathe
because the VFD with the new cover takes up almost all the space on back of
headstock. See next photo.
Here is what the back looks like. I took this photo when I had the
headstock removed from the lathe while moving the lathe.
The magenta arrow in photo points to a 1/4" deep by 3/4"
wide dado slot in the bottom of the 2nd level plywood. It is not easy to
see in photo! The back plywood extends up 1/4" into this slot. Thus
the back plywood did NOT split, when I glued and screwed the 2nd level
plywood down to the back plywood with 2-1/2" decking screws.
If I had to do again, I would replace the plywood level 2 shelf
support triangles with a custom bent aluminum bar. See red arrow in NEXT
photo.
The aluminum bar would come down from one of the nuts under 3rd
level support (green arrow in photo) to the bottom of plywood triangle
(blue arrow in photo).
Aluminum Shelf Support on Oneway Shelf
This photo shows the shelf on the back of my Oneway 2436 lathe. Note: See "2nd Generation Shelf" photo above for the front view.
The red arrow in photo points to an aluminum shelf support that I
created out of a 1/8" thick by 3/4" wide piece of aluminum bar
stock from local hardware store. This chunk of aluminum takes the place of
the plywood triangles in the above design. If, I had to do again, I would
use aluminum bar in the above design. Easier and better looking.
Note: The plywood is attached to the back of the Oneway headstock
with 4 black 5/16" socket head cap screws. You can see 2 of them in
photo. I used some 1/2" hex nuts between the plywood and metal
headstock to "stand off" the plywood so it would clear the round
part of headstock. All of the steel used by Oneway is hard stuff. I think
it may end up getting work hardened when it is bent and welded by Oneway.
Thus, drilling and tapping the holes for the bolts is no easy task!
Looks great. Estimated cost and time to build?
Great details
Thanks for posting
Very well thought out. Thanks for sharing the thought process and how the shelf evolved.