HEX broach too big for our manual press

[Ken Patton]

Originally Posted by Tottanka

... Broach is too long ... Are there any solutions anyone has for this kind of a problem?

We have the same issue with the arbor press in our shop. Our solution was to start the broach using our lathe, which allows us to carefully align the broach to the hole and get the broach deep enough to now fit into our press. We try not to put too much load on the tool when it is in the lathe since we don't want to overload the lathe axially (which would damage the bearing in the lathe).

Ken

EDIT: The amount of load we put on the part+tool when they are in the lathe is very small - just enough to start 2-3 teeth of the broach - which is enough for it to then fit in our press.

[Tottanka]

There is about a 6'' difference between the gap in the press and the length of the Broach, so it isn't really close to fitting ATM.

We will try both the Lathe broaching and the lower platform approach and post results here.

[AnthonyDV]

Originally Posted by Ken Patton

We have the same issue with the arbor press in our shop. Our solution was to start the broach using our lathe, which allows us to carefully align the broach to the hole and get the broach deep enough to now fit into our press. We try not to put too much load on the tool when it is in the lathe since we don't want to overload the lathe axially (which would damage the bearing in the lathe).

Ken

I admit that I have done this, but on a big lathe. Some of Devin's (another mentor) projects have required far more force but I still can't recommend doing this.

[Bill Davis]

However the method of driving the Hex Broach, be careful with your fingers. As the broach passes through the part being broached, the tooth next to enter will take skin with it.

Have you been caught broaching in the classroom yet?

[Craig Roys]

We had the same problem when we started using hex. We use one of these for broaching and just about any other press needs...not too big, but plenty of force. There is a floor version as well.

Dake 10 ton press.

[Michael Corsetto]

Like Anthony said, we have used lathes and mill knees in the past to hex broach. Neither are recommended.

We've spent the last few years scouring Craigslist and found a 5 ton/8 ton compound arbor press similar to this: http://www.machine-recycling.com/Sep...bor-press.php6

The travel is plenty and the press is very rigid/square. As a bonus, I'm pretty sure the tool will outlive any of us on the team

If you spend long enough looking, you can find a good deal on one. We got ours for $550.

-Mike

[Bill Davis]

However the method of driving the Hex Broach, be careful with your fingers. As the broach passes through the part being broached, the tooth next to enter will take skin with it.

Have you been caught broaching in the classroom yet?

[aldaeron]

Check out this thread for some ratcheting presses that are large enough for a 1/2 hex broach. I have a post on there on how we got the very sloppy Harbor Freight 12 ton shop press to work well with some simple mods. We really do need to find time to make a video of it in action.

-matto-

[techhelpbb]

Either bolt the press to a steel frame suitable to support the pressure and put blocks under the work piece when you run out of travel or:

I bought this recently and it works fine for the AndyMark (Dumont) broach:
http://www.ebay.com/itm/261742003018

Mine is currently in my garage on a custom cart made of 2x4 and 3/4 plywood with locking casters. It was lifted with a car engine hoist. Shipping from Ohio took 1.2 days to NJ. The ram has a 1/2" hole in the end and there is a metric set bolt which doubles as a stop when the ram is lifted. Put a longer metric bolt in there and you are all set to broach. Mine has a casting void at the bottom which makes no difference to operation.

Also consider this (see Craig Roys post above):
http://www.ebay.com/itm/261956665389

The advantage of the Dake press is the pressure gauge.
You can use a short ram hydrualic piston from Harbor Freight filled with glycerin as a pressure gauge plate on the previously listed ratcheting arbor press.

[sanddrag]

Ours fits just barely on our Grizzly arbor press. They don't sell the exact model we have anymore but judging by the ones they do have, it's probably a 5-ton. 2-ton is pretty small for broaching 1/2" hex. I'm a big guy, and we've broached certain things 1/2" hex (steel) to where I had a 4 foot pipe over the handle and was just about hanging off of that to get it to go. On a two ton press, you'll struggle with anything more than 6061 aluminum, about 1/2" length through bore.

If you do want to keep your press and use it with longer broaches and things, there's two things you can do. You can chuck up the arbor in a 4-jaw chuck on a lathe and drill a hole into it, or you can build a custom table for your press, that has a sturdy place for you to set the part below the press.

[Hikel team 319]

this is the setup that 319 uses as Ty was explaining it earlier in this thread

[Jared]

Don't broach using a lathe or mill - the thrust bearings aren't designed to be loaded while they aren't spinning and aren't usually cheap and easy to replace. Also, you'll likely end up moving the head on your mill, and you'll need to tram the head before you use it as a mill again.

[RoboChair]

Originally Posted by Jared

Don't broach using a lathe or mill - the thrust bearings aren't designed to be loaded while they aren't spinning and aren't usually cheap and easy to replace. Also, you'll likely end up moving the head on your mill, and you'll need to tram the head before you use it as a mill again.

I've broached with the knee of our bridgeport mill against the turret arm. It works and it sucks, and it isn't detrimental to the machine if done right.

[Chak]

Originally Posted by RoboChair

I've broached with the knee of our bridgeport mill against the turret arm. It works and it sucks, and it isn't detrimental to the machine if done right.

Can you explain how to do it right?

[RoboChair]

Originally Posted by Chak

Can you explain how to do it right?

So, you will need a few things.

A knee mill
A hex broach(or other broach)
The part you want a fancy hole in
Some piece of metal with square ends(like really square, you have a knee mill there is no excuse) and a hole through the middle

Your support piece needs to be at least as long as the broach or have several progressively longer pieces if you find the total travel to be in issue. Don't use multiple pieces to support this set up, it's a good way to break your $200 broach that you are trying to use cheaply. Take your sweet time.

Place your first or only support block(tube) on the back of the knee ways and make sure it is stable. Place your work on top of the support so that it lines up with the hole. Line your broach up with the whole set up doing as best as you can to have everything perfectly straight, take your time please. When you are sure you are good to go begin cranking the knee of your mill up slowly until it makes contact with some part of the turret(the part that nobody EVER moves back and forth on a mill but you could if you wanted) slides on a flat part only. Ours has a dovetail slide and we used the further down bottom flange of the dovetail. If you plan to do this often, just set up the turret so it is set up perfectly over the Y-axis knee ways.

This next part is really important.

When you are sure it's settled and ready to broach, crank the knee up a full turn and back it off to let the broach recenter itself. Keep doing this full turn back off step until you run out of travel, repeat until done. The backing off step may not be 100% needed, but it will prevent the chance of many unwanted things happening to your set up.


EDIT: Done carefully, it can be managed with one person, but 2 makes it far easier and you can take turns cranking.