how would you make this

[extsuba]

Hello
I would like your thoughts on how you would make this -
1.3 at the widest part
1.774 tall
1.06 bore
.250 304 stainless steel
and the machine specs 4000rpm spindle
nmtb30 taper
I am having trouble making these - 12 at a time in a fixture
just want to see a fresh perspective on this
Thanks

[txcncman]

A lot of ways to make parts similar to this. You did not include tolerances to be held.

#1)

Saw cut material to 2" X 1.5" X 1/4"
Place in vise and drill and countersink 3 mounting holes inside the 1.06" bore
Place on fixture using 3 mounting holes and countersink hex cap screws
Mill outside profile
Place in soft jaws milled for outside profile
Mill bore and drill and tap hole

#2)

Saw cut material to 2" X 1.5" X 1/4"
Place in vise with part rotated 90 degrees from photo
Drill 1.06" to size with inserted drill (mill to finish if needed) and drill and tap hole
Mill narrow side (shown as lower side in photo)
Place in soft jaws rotated back to what is shown in photo holding across finished flat and inside of 1.06" bore
Finish mill outside profile

[extsuba]

+/-.005
I have a run of 500 parts
I was thinking of :
drill out center hole
mill to finish diameter
drill screw hole
and then hold via internal collet and dowel pin hog mill the profile then finish cut
just not sure if that will be to much over hang

[extsuba]

Saw cut material to 2" X 1.5" X 1/4"
Place in vise and drill and countersink 3 mounting holes inside the 1.06" bore
Place on fixture using 3 mounting holes and countersink hex cap screws
Mill outside profile
Place in soft jaws milled for outside profile
Mill bore and drill and tap hole

sounds like a good Idea

[jimhurlburt]

A slightly different angle.

If 1-1/2 x 1/4 flat bar is good enough for thickness and finish.

Cut lengths in 2" increments that fit on your machine.
Make a fixture that will hold one or more of them clamped to the table
Bore the large hole, drill and tap the small hole on each 2" segment of the flat bar.

Cut the flat bar into 2" lengths with a saw.
Make a fixture with one or more stations, a round piece that just fits in the large hole with free clearance -- it should be a few thou shorter than the thickness of the work.
A clamp that screws to the tapped hole and the top of the round piece, holding the work down all around the perimeter of the large hole. Probably two or three 1/4 grade 8 bolts in the fixture pin, the #8 or #10 bolt in the tapped hole to index the piece.

Finish the outside surfaces.

[Delw]

try this
3/8 stock mill complete hole chamfers everything.

then flip over and cut jaws to profile of finished shape. face and chamfer edges
finished

we do this with remington 700 barrel lugs quite a bit.

[TechGuy5002]

What about milling or drilling out the center hole and water cutting the outside shape? I suspect that the outside except perhaps for the flat edge doesn't need a tight tolerance. I assume your using flat bar, and using the flat edge of the bar with no milling.

[uli12us]

I would make these parts with first milling the two big and eventually the 2 small holes in a part of steel, that are connected at the straight edge, with a distance of 0.42". Than make a aluminiumplate and two centers for the holes and use a big washer and screw to secure it on the plate. then you can mill the outer conture. After that you take an 0,4" mill to remove the connection of the parts, later you can make the finishing cut. If your part will turn, than you must use the small hole as well for secure.

[Anders6612]

Make a sturdy steel fixture with say 12 drilled an tapped holes, with say 3/4-1" screw.
Secure the material over it with clamps, and finish the 1.06 bore centered to the
tapped holes. Now, tighten screws in the holes with thick washers aprox, 1.23" wide
and tighten. Then finish the outside operation.

View image: Image3

[fizzissist]

You'll need a fixturing plate, for your 12 up... depending on your table size, maybe 6 up on each side of the table... that way you can be loading/unloading one side while the other side is running. (lock the door so OSHA don't see you doing this)

1. Blank to 1.5 x 1.9 (or whatever you're comfortable with and is within the raw mat'l size... you could waterjet 'em, but it's expensive. You could plasma, BUT... I wouldn't. Too much time removing slag, HAZ, and tolerances all over the place. 2" wide 1/4" thk plate (assuming your finish thickness tolerance will allow) is ideal for bundling up and sawing off 8 blanks at a time.

2. 2nd OP is to take the square blanks, rough then finish the large bore, then drill and tap the small hole. Is it a through hole? (don't matter, BUT... drill the hole CAREFULLY, TO THE SAME SIZE ON ALL THE PARTS.... we'll use it for locating later).

3. .. Now you've got your finished holes, you'll make a dozen simple little caps (we'll call these "clamping plugs") with a shoulder.. small dia is .001" less than the bore of the part, and slightly less than the thickness of the part long. Large dia is about 1.25" and about 1/8" thick. Put a 1/2" hole thru in the middle. This piece will go thru the bore and provide primary clamping force to hold the part on the plate.

------ an alternative to this would be 3 dowel pins that would locate the bore with some sort of clamping bar arrangement. PITA, but it works too.

In your fixturing plate, tap a 1/2-13 for the clamping plug with a dowel pin hole for locating off the tapped hole, spaced accordingly.

4. 3rd OP is to load up your parts on the fixture plate, tapped hole down on the pin if they're not thru, clamp down with the plugs, then route the outside countour.... If the tapped hole in the part is thru, you can easily flip the part and contour a chamfer on the other side too if needed.

5. Timesavers or whatever to the front and back face, engrave "tooling and fixturing design by fizzissist" in Helvetica 18pt and you're done.

One caveat...depending on your control and programming.... be sure your finished bore is round. Some controls/programming methods can result in a bore that isn't, off by a thou or two. That'll affect your plug's fit.

I've used this method a lot for flat 304 pieces, and the clamping is plenty to get the tool in and remove the outer mat'l efficiently.

Hope this helps... May not be for your application/shop, but it's worked for me.

[fizzissist]

If you've got a pair of Kurt vises (or quality equivalent!) and some Talon Mitee-Bite clamps, you could use 3/8" thk mat'l as Delw suggests, and clamp up 2 in each vise. Completely machine face, inside and outside of 2 parts while loading the other vise.

In a pair of soft jaws, contour out pockets to hold onto the profile. Flip the parts over for your second op and all you have to do is face the "wasteboard" mat'l off, and run a chamfer.

This would make for a nice part, but only give you 2 at a time machining. Much faster setup too. But, gotta weigh your mat'l cost into the time factor.....

Your call. Good luck!

http://www.youtube.com/watch?v=IslBgaqGp0k&feature=related]Full Introduction Movie - YouTube

I've used this method too, and it's excellent. These are great jaws.