Hex Socket Broaching.

[Anorak Bob]

While searching through the old threads looking for some information regarding drill press broaching, I rediscovered this - http://americanmachinist.com/practical-ideas/quick-custom-hex-sockets

I don't know if anyone has had a go using this technique but I might have a crack at it this afternoon. If I do I'll post a report.

BT

[Dingo Dog]

Cant see why it wont work, there is a bloke on utube that made a punch/die out of a big bugger allen key. Punched right thru steel, maybe it was alloy, cant remember.

DD

[WCD]

Bob,

I have broached hex sockets in the lathe, just using the tailstock, but only tiny ones (1.5mm AF) because the broaching forces are high unless you use a rotary broach tool. Also did some larger hex sizes (up to 3/8 inch) by hammer, but got a fairly torn up surface finish in a mild steel workpiece. Given the force required, hammering on the end of a workpiece held in the lathe headstock is cringeworthy. Better support the work on an anvil or heavy steel block.

Rather than making a separate guide for the broach, it may be easier to start with a longer piece of stock and include the broach guide bore as part of the workpiece, parting off the guide section later. From memory I proceeded with the broaching in small steps, cleaning out the chips with a short-flute drill between steps, with a risk of drill breakage due to the interrupted cut on work hardened material.

Have fun.

Cheers,
Bill

[.RC.]

That is a good idea...

Be aware though that your usual quality hex headed screws are grade 12.9... When you use an allen key in them the heads do not deform if the screw is tight...
I have some chinese hex head grub screws here... All soft as... The heads deform quickly on them..

[Stustoys]

Doesnt sound very Bob, sounds more Stu. :D
I liked the look of the DIY rota broaches....but if the simple version works. Havent needed to try either yet.

Couldn't you move the setup to a drill press instead of hammering away on your lathe? (I guess it depends what size you have in mind.)

Stuart

[Pete F]

Good God Bob, hammering a piece if sawn off hex key through a hole to "broach it". :oo: Clearly the gentleman concerned had no respect for his lathe's precision headstock bearings. If you wanted to do that why not just press it through with an arbour press and save the lathe for what it's intended for. As far as I'm aware, being an anvil isn't one of those purposes. At least with an arbour press or similar you're likely to have a small amount of control over the end result, and can guide the "broach", as opposed just smacking it with a hammer and hoping for the best.

If you want to do this type of thing with any sort of regularity just make up a rotary broach. There's plenty of designs on the net and they all require only a couple of bearings. The most difficult thing in fact seems to be in grinding the broach and setting up the tool. Once you make one you'll realise why.

[Oldneweng]

It is interesting that this subject has come up now. Only a few days ago I was contemplating the feasibility of broaching a hex socket in order to make adjustable locking levers. I have installed them on my mill, and on the cross slide and compound slide locks on the lathe. They are hugely quicker. I dont need to move around to the other side of the mill to see the cap bolt, I can just reach around. The difference is enormous. The problem is that now I see uses for them everywhere. Every time I turn around I find another potential use. I could use about 30 on my SCMS and the stand I made up for it.

Just one more thing to do.

Dean

[shedhappens]

adjustable locking levers. I have installed them on my mill, and on the cross slide and compound slide locks on the lathe. They are hugely quicker. I dont need to move around to the other side of the mill to see the cap bolt, I can just reach around. The difference is enormous.

Just one more thing to do.
Dean

"Just one more thing to do." I know......show us a foetoe :?



The problem is that now I see uses for them everywhere. Every time I turn around I find another potential use. I could use about 30 on my SCMS and the stand I made up for it.
Dean

"SCMS" lost me with that one also :doh:

[Ueee]

Sliding compound miter saw?

Waiting to see your efforts Bob....

Ew

[Anorak Bob]

First off. No Class C Precision Timken taper bearings were hammered, abused, or otherwise mistreated in this exercise...:)

I had a box fresh, pretty sharp cornered 6mm hex key that I chopped an inch off and ground on the No.1 ( its first task ). I realised later that I could turn the key in the lathe which would have produced a lot less mess because I had to dress an out of round wheel on the grinder before I touched the key. Anyway, my first test was with a piece of 1214. I used a 6mm endmill to finish bore the hole and then turned a shallow counterbore to act as a guide for the key - broach. Worked well but I don't see a great demand for 1214 cap screws. :rolleyes:

Then I tried some 4140. Different story. Maybe the 6mm hole was slightly larger than 6mm because the key only cut in the corners. Or maybe it was just blunt.

The bloke who wrote the article said he used vice grips to wobble the key out of the hole. I held the key in the vice and belted the bar off with a big Thor copper mallet. It was stuck in tight even in the gumby leaded steel.

I think I might have a look at one of those home made rotary broaches Pete mentioned.

BT

ps. a few years back I posted a link to a YouTube clip showing a bloke making a toolpost for a 102 lathe. Sadly I didn't save the clip ( probably didn't know how!) because he showed the making of some socket head cap screws using a rotary broach on the little Schaublin. They were perfect.

[oohsam]

Intersting stuff!


https://www.youtube.com/watch?v=M3Ul-s9_MA0

[Oldneweng]

Sliding compound miter saw?

Waiting to see your efforts Bob....

Ew

Ueee got the prize. An acronym from the light side of the forum. Nobody there would dare to ask what it meant.:D I started there but quickly moved to the dark side. All I go back for is some stuff from BobL. I will get back there one day. When I have my shed sorted and my $1400 table saw is removed from its box. It was bought on the same day as my mill. It is currently serving my mill. As a table for cutters, collets etc.:D

Shed, what did you want foetoes of specifically.

318188
This is one of the levers. Available with various lengths of thread and in various thread diameters. The handle can sit in any one of 6 positions. Pull out against a spring, rotate and release. My cross slide and compound slide used to have 6mm grub screws. Find the allen key, scratch around to find the hole. Can't quite see it so move around a bit for a better look. Fit the allen key........ Or reach over and give the lever a quick twist. The carriage is locked with a 16mm spanner on a nut. I am wondering what I can do with that. Now I have seen this thread I know what to do. Like Bob found, forget this idea and go with the rotary broach. All 3 axis on the mill are locked with these levers in 10mm. They adjust to keep the handle out of the way. Sometimes I flip the handle right around when loosening and it won't lock up as it hits the table which has now been traversed over the top. I then have to turn the handle around 360 deg. I soon learnt not to flip them too hard. The mill came with little flip handles that were basically useless. Needed pliers to tighten. I started using 10mm SS cap bolts that I had available. There was a thread about this at the time. IIRC somebody pointed me to these handles and now I am addicted.:D

I have looked at a number of broach ideas tonight. One used a broken HSS tool as a broach but the other idea was from Mikes Workshop. The HSS had to be ground to shape. Mike likes it easy. Machine a broach from silver steel then harden and temper. He finished up with a broach holder that took a number of different sized broaches. This saved on the silver steel. Only needed a little piece. I won't try to explain. Just look at http://mikesworkshop.weebly.com/rotary-broaching.html. He also mentions a broach for use on the mill.

Dean

[shedhappens]

Sorry for hijacking your thread Bob,




Shed, what did you want foetoes of specifically.

318188
This is one of the levers. Available with various lengths of thread and in various thread diameters. The handle can sit in any one of 6 positions. Pull out against a spring, rotate and release.
Dean

Thanks Dean, I get your drift with the levers now.

As for the "SCMS" ? I thought that you might of had a new fangdangled metalworking tool that I hadn't heard of. I have one of those things also, I learned very quickly to use a clamp when cutting aluminum with the "SCMS", one time I was cutting a bit of ally angle and all hell broke loose, my hand looked like it had been in fight with a cornered angry feral cat, :rolleyes:

shed

[Oldneweng]

Sorry for hijacking your thread Bob,



Thanks Dean, I get your drift with the levers now.

As for the "SCMS" ? I thought that you might of had a new fangdangled metalworking tool that I hadn't heard of. I have one of those things also, I learned very quickly to use a clamp when cutting aluminum with the "SCMS", one time I was cutting a bit of ally angle and all hell broke loose, my hand looked like it had been in fight with a cornered angry feral cat, :rolleyes:

shed

I've got one of those feral cats around here. If I ever manage to get it lined up with the cross hairs? It is a black one and as canny as hell.

Anyway, I built a stand for my 12 inch 909 SCMS that extends out to over 4m from memory. Everything is clamped with cap bolts screwing into welded on nuts. Heaps of them. The SCMS also has quite a few 6mm clamp bolts. All are fair game for changing to locking levers. Speed things up no end and I might even bother to get it out to use. The stand is currently dispersed over a couple of acres and the SCMS is sitting on a desk in the carport. The left side has limited clearance for extending wood due to the shaper parts still sitting on a table there. The ram stops wood effectively.:D

Re the 909 masters name. Don't start me there. I looked at SCMS's some years back and the only one that was any good was the Makita single round table version because every other one I looked at with the 3 part table was not flat. Walked into local Gasweld dealer (back when I was still talking to them) and asked for a metre ruler. Went down the row checking levels of the tables right up to the Dewalt. All varied by up to 1.4mm in height from one side to the centre table. All obviously made in the same crap Chinese back yard shed. Not one had a level surface from one side to the other. The 909 is the best one I have seen except for a little Ryobi my step son lent me for a while. The Makita had a single large table so not a lot of opportunity for variations in level. As is usual in these situations, this particular type is not very common anymore.

Dean

[Pete F]

I think there is better material out there in regards to rotary broaching, although nobody could deny broach in the video above is certainly simple!

Bob if you want to persist in smacking hex keys through with ever bigger hammers, you may have better luck grinding the hex with similar front rake and side clearance as the rotary broaches.

[Anorak Bob]

I think there is better material out there in regards to rotary broaching, although nobody could deny broach in the video above is certainly simple!

Bob if you want to persist in smacking hex keys through with ever bigger hammers, you may have better luck grinding the hex with similar front rake and side clearance as the rotary broaches.

I never made it to the persisting stage Pete and the only hammer I used was the Thor to remove the " broach ". I've moved on from hex key broaching.:)

Bob.

[Pete F]

Oh come on Bob, don't be like that, that's why different sized hammers were invented ... there's always a bigger hammer to solve the problem :D

Seriously though, good decision. I look forward to seeing the rotary "Boboach" in the next few weeks, no doubt comprising impeccable workmanship as always.