Would like to Borrow/Rent/Buy a 3/4" square broach.

[KT_NorCal]

Recently picked up my first lathe which is a 1942 Monarch C14... and like all old lathes it has a few "challenges." One of them is a standard Monarch issue where the handles on the clutch start/stop rod have wallowed themselves out. This caused the PO to do some creative engineering which I need to fix. Anyway, I will need to make a 3/4" square hole in 3 steel bushings in order to get the thing running properly again, so if you are in the SF Bay Area and wouldn't mind lending or renting one out that would be ideal, but I'm happy to consider buying one if you live farther afield and have one gathering dust...

Thank you!

 

[gbent]

You may be able to go to horror fright and buy the cheapest thing with female 3/4 drive. Get them in impact so you don't have to turn the chrome.

 

[EmGo]

I will need to make a 3/4" square hole in 3 steel bushings in order to get the thing running properly again, so if you are in the SF Bay Area and wouldn't mind lending or renting one out that would be ideal, but I'm happy to consider buying one if you live farther afield and have one gathering dust...

Pioneer Broach, one in LA, one used to be in Atwater ? Go to the Atwater one. Not sure now but they did stuff like that much cheaper than you will be able to. 3/4" square won't be much fun to get straight and push, they are pretty nice people and not unreasonable at all. Call them up, they will tell you what size to drill the pilot and they'll pull it, not push. Better and straighter.

 

[SIP6A]

You would have better luck taking your parts to a shop that does broaching and pay what it costs. A 3/4" square broach runs about $600.00 I can't imagine any shop just loaning one to some guy on the internet.

 

[richard newman]

Can you adapt a square hole sleeve or bushing?

 

[just Dave]

You may be able to go to horror fright and buy the cheapest thing with female 3/4 drive. Get them in impact so you don't have to turn the chrome.

Great idea, low cost, decent steel, easy to get.

 

[tft1987]

if ya give me a drawing, i can rip some out on my 5axis waterjet for ya...

 

[L Vanice]

Can you adapt a square hole sleeve or bushing?

To clarify, most industrial supply houses sell steel sleeves with square holes already broached in them. Sturdy Broaching is a manufacturer of them.

products-sleeves - Warren, MI - Sturdy Broaching Service

www.sturdybroaching.com

Larry

 

[Superbowl]

Just drill a 3/4" hole and file. To speed it up mill the hole close to square with a 1/8" mill then file it perfectly square.

 

[Mr_CNC_guy]

Is this something that could be milled in halves and then the two halves braised or welded together?

 

[KT_NorCal]

Can you adapt a square hole sleeve or bushing?

I don't see why not... as long as it has a OD that I can turn down to appropriate size.

 

[KT_NorCal]

Just drill a 3/4" hole and file. To speed it up mill the hole close to square with a 1/8" mill then file it perfectly square.

This is plan C. May just do it, but have a bunch of other things I need to finish in the limited shop time I have, which is why I was trying to find a broach.

 

[KT_NorCal]

To clarify, most industrial supply houses sell steel sleeves with square holes already broached in them. Sturdy Broaching is a manufacturer of them.

products-sleeves - Warren, MI - Sturdy Broaching Service

www.sturdybroaching.com

Larry

Thank you for the link. They say they do custom small run orders which might solve the problem if they aren't too spendy. I essentially need their standard one with just a larger OD. I'm fine turning it down myself as I'm guessing the two handles have a range of fit. They are just fixed with a set screw through the joining ID/OD so really only need to be an easy press fit.

 

[KT_NorCal]

Great idea, low cost, decent steel, easy to get.

I hadn't thought of this option and stopped by on the way home today, but couldn't find anything that would really make for a good substitution. I like the internal square ID stock route.

 

[KT_NorCal]

if ya give me a drawing, i can rip some out on my 5axis waterjet for ya...

Thanks for the offer, will keep it in mind if I get unduly frustrated... sounds a bit epic doing something that simple with a machine so epic. Like fly swatting with a tactical nuke... ha.

 

[john.k]

The way Ive done square hole machine handles is to make the square in two halves ,and weld them together .

 

[metalmagpie]

Here's how I approached a similar problem. Note that I used a milling attachment on the lathe but there is no reason you couldn't do it on a mill.

http://nwnative.us/Grant/shop articles/shaper wrench

 

[ratbldr427]

The easiest way to do it is to simply slot the round bar then weld a filler piece of sq or ret stock in the open side after you insert some sq stock in the slot to keep every thing parallel.I use a .005"shim on top of the sq insert to make sure the hole does not close up during welding.

 

[richard newman]

KT, how long are the bushings that you need? I've broached key slots on bores in the B'port by grinding a low rake chisel from a hss blank (old reamer shank) and stroking with the quill, advancing the table a thou or two at a time. I've also silver brazed a piece of hss from a parting tool onto mild steel. Takes less time than you'd think. You could easily do the same in all four corners.

Being primarily a woodworker, with only basic metal machinery, I often have to improvise. I find I can get it done myself in less time than it would take me to drive to a shop that has the correct equipment and tooling.