I need/want an Arbor press

[jwmelvin]

The amount of pressure is adjusted by how much increase from the previous shim behind the broach is.

I’m not clear on why people say this. A broach has a fixed increment from tooth to tooth, and that cut depth times the number of teeth in engagement will control the force required. If you mean using such small shims that only one or two teeth at the end of the broach cut for a given shim, then sure. But that seems impossibly slow. And would put all the work on the last tooth or two. Basically no better than shaping in a lathe. Reducing the force for a fully engaged broach would require changing the angle of attack or modifying the broach itself.

 

[jbobb1]

I've broached keyways over 1 1/4" wide on a 90 ton Dake press. It's dangerous if you don't know what you're doing and what to look for when a problem arises! If you're doing small stuff, and you're not comfortable using a hyd. get a arbor press.

 

[addertooth]

I’m not clear on why people say this. A broach has a fixed increment from tooth to tooth, and that cut depth times the number of teeth in engagement will control the force required. If you mean using such small shims that only one or two teeth at the end of the broach cut for a given shim, then sure. But that seems impossibly slow. And would put all the work on the last tooth or two. Basically no better than shaping in a lathe. Reducing the force for a fully engaged broach would require changing the angle of attack or modifying the broach itself.

If you start with a heavy bite at the First tooth, that stress is along the entire broach (more potential for flex and mis-alignment). If you start the bite mid-broach, it is a shorter length that is bearing that stress, and is less likely to deflect. Yes, the tooth to tooth cut is defined by the broach, but, biting hard at the first tooth is more likely to create drama without a well-aligned jig.

 

[jbobb1]

Typical broach nests or bushings are usually machined so the first tooth of the broach just starts engaging the bore of the part you're working on.

 

[addertooth]

Yes, the standard bushings do that. But then, the very first pass of the broach only first engages at the corners of the broach, then you can add shims for subsequent passes (while using the First bushing). This way you control the first "engagement tooth" of the broach. This is for people who are concerned about the broach breaking/shattering. I tended to be pretty aggressive with big beefy broaches, and a bit more cautious with smaller and more narrow broaches.

 

[gonzo]

Be careful, this copy may (probably ) be smaller than the original that you may have seen elsewhere.
Note that no specifications are quoted in the ad.

 

[alloy]

I bought this off Facebook. Using it to do 5/16" keyways on 1-1/8" diameter collar clamps for my transmission mods. I had to shorten the broach about 1/2" for it to work. I'd rather have a ratchet arbor press, but the price on this one was right and it was local.

I completely agree on using a hydraulic press. I tried it on my 20ton HF press once, and never tried it again. The broach didn't go through straight and thankfully I didn't break the broach. It often does the same on my arbor press, but I can feel it getting harder to push the broach through and straighten the broach and not break anything.

 

[benmychree]

The thing about arbor presses for broaching is that unlike hydraulic presses, pressure is relieved at every stroke and the broach is allowed to realign itself, not generally the case with hydraulic presses, especially with cheap ones that do not have tight guides to keep the ram in alignment. I have seen key broaches start to buckle from misalignment, but I have never broken one.

 

[MrWhoopee]

I've done a lot of broaching up to 3/4" in a poorly built hydraulic press. I've also broken a few broaches. In a hydraulic it's wise to push, back off, push again, etc. Always orient the broach so you can see the profile of the teeth. This makes it easier to tell if it is digging in and going off vertical. If this happens, push the BUSHING out, turn the part over and start again. Also, do not stand directly in front of the press. The broach will break across its thinnest section and the shrapnel will most likely fly in that direction. Stand off to one side.

I have a 3-ton arbor press nearly identical to the one pictured above by @alloy. Found it on FB Marketplace for $75 along with a $50 6 in. Buck Adjust-Tru 3-jaw. It was a Really Good Day. Anyway, the press is also a little too short for a C broach. Using a thinner shim to start each pass is one solution. I'm considering counter-boring the end of the ram to gain more height, with a removable shoe fitted to the c'bore for situations where the extra height is not needed.

 

[alloy]

Here is my setup for broaching the collar clamps. I do a first pass with no shim, second with one thick shim, 3rd with another thick shim, and 4th with a thin shim I made from steel strapping. Your can see nthe shims on the left. This produces the perfect depth to hold the stepped key I make that holds the speedometer gear from spinning on the output shaft.

I have to watch how it's working because the broach ends to tilt backwards and will cut the keyway angled.