A simple drill press hold down clamp for you

[BCRider]

It's raining solidly today. So I made some keys.

They are very simple flat plate keys for a cheap lock in a case I use a lot. It came with two and I lost one a couple of years ago. I wanted some spares. So since it's a very simple "suitcase" lock I was able to make some from flat plate.

But then it came time to drill the key ring holes in the keys. And the vise grip hold down I often use for this sort of thing was fighting me and the wing nut simply did not want to go onto the stud..... So I stopped and made the simple hold down shown below in about 30 to 40 minutes. It's something I've intended to do now for quite a few months.

It's good just over 1.5" of height before the front portion is at the wrong angle to apply pressure at the toe.

Material is 1/4" HR mild 1.25 wide by 4.3 cut from a piece of scrap plate. A 27/64" hole was drilled for a 3/8 stud. It was bent in the vise using a piece of 7/8OD black pipe as a bend radius mandrel with some assistance from my 20oz ball peen. Care being take to get the plate square to the pipe.

The hole crushed closed a little plus I also filed in some angles along the length of the hole to form a sort of X shaped slot to permit the angles of the stud as shown to cover the range of height adjustments.

And after rounding the toe and heel with a file or some belt sanding and the bend is made do check for any rocking and correct it with some extra filing or grinding to get the clamp to sit evenly on the flat and on something around an inch thick.

[BCRider]

The end of the stud was given what I've read is called a "Higby" end treatment so the wing nut slips on and starts onto the threads with almost no special care needed at all. Here's a close up of such an end. It's easily done in the lathe with the chamfer tool to cut the angles and the almost but not quite minor diameter relief. The sharp start of the first 1/2 turn of the thread is then filed away with the lathe turned off to leave a nice clean entry to catch the thread on the nut.

If you've never tried doing one of these I strongly recommend you have a go for studs where you want the nuts to start onto the threads super easily.

Here's an example on a piece of 9/16" all thread to more easily see the steps. First is face the end and cut most of the thread away until the nut slips on over the stub easily but without a lot of play. I found that it's better to leave the last bit of thread root showing rather than take it down fully. It makes for an easier start that way. Here's what we end up with....



The rough flashing and sharp entry of the last thread has to go. I file the flashing and first part away over about a 1/3 to 1/2 of the way around the stud until I'm left with this nice clean entry. Hopefully you can see the shadow of the clean tangential flat from the file.



The result is that one can literally drop a nut onto the stub and give it a flick to spin it onto the thread. No more fumbling. Takes about 90 seconds to do it on just about any size once you have a couple under your belt.

And just to come back full circle here's the keys that started it all....

[Cenedd]

Nice BC. May have to pretend to myself that I'll get round to copying those!
It seems to be more commonly referred to as a "Higbee" thread although it sounds like it was a firefighter's name and may have been "Higby". Not trying to correct you - especially as I'm not sure which is actually correct - but if you're searching, the alternative spelling may be helpful.
Also seems that sometimes the cut can be done on an angle so as to draw the fitting together more... although given it was originally supposed to have been done by hand with a file, I would guess this is a later, optional revision.
Pic here

[Doozer]

Higbee is in the older machinist's handbooks but not the newer ones.

-D

[gellfex]

That'll sure work, I've got some similar hold-down piece meant for the mill. But my DP has one of those Vise Grip type hold downs that works pretty well most of the time, especially for holding the small 2.5" vise when I'm tapping #10 or greater.

[Dan_the_Chemist]

Nice. Do you have downloadable dimensioned drawings and a BOM ???

[RSG]

Damn, now I gotta make some of those.....😁

[BCRider]

Nice. Do you have downloadable dimensioned drawings and a BOM ???

Yep. BOM- whatever is in the scrap box....



Mostly I think I was caught off guard at how well this worked right out of the gate and how simple it was. Previously I'd been all focused on the similar but a lot more complicated to make version with a round axle much like THIS STYLE.

But it seems that cheap, quick and dirty is all that's needed to work just super. At the moment what with making the stud collar to stop it falling through I think I'm up to around 90 minutes of work on this. But of course now that I know I'm sure I can do it all in about an hour. Much of the extra time was spent trying different things.

I need to do one more though. The one shown is nice for larger items that would crowd a longer span clamp off the outer edge of the table. But I also want one that can span into the center of the hole. So the next one will be a little longer and more of a 60-40 split on the length so it can reach the center.



Oh, I also added a thin aluminum disc threaded onto the stud. And I Higbee'd the other end and dimpled the end of the thread on the T nut. Now I can hand thread the stud into place and finger tighten it against the thread dimples and the stud doesn't try to fall through and out of the table. I think I'll do one more T nut and stud like this and between the two that'll be enough for just about anything that needs to be held downwards instead of from the sides. I made the mistake of threading the whole way through so I needed some thick CA and accelerator to bond it into position. Next one will use a taper tap and I'll only start it then "swage finish" the thread with the actual stud so it's tight. Likely won't need any bonding that way.

Another option that would work for aluminum is to file some cutting notches into the end of a piece of the threaded rod and use it as a "tight fit" tap. That would only be good for working in aluminum, plastic and possibly brass though.

[Bob La Londe]

nice. Do you have downloadable dimensioned drawings and a bom ???

bwahahahahahaha

[BCRider]

bwahahahahahaha

I know, eh? He's quite the cutup!

One last bit that I forgot to include and that might be helpful. The T nut that permits the stud to sit up hard against the inner end so we don't lose any travel.

Cut the material from some 1" square mild to 1/2" thick. Shoulders and end cut with a 3/8 end mill to give me a 0.2 depth for the shoulders. This is dependent on the drill press table of course but the thinnest slots were around 0.23 on my DP and of course we don't want the T nut sticking up above the surface.

The cove was cut with the same 3/8 end mill. Bigger stud sizes would use the same diameter end mills. The center for drilling and tapping was "spotted" with a 3/8 drill running in the cove so provide the degree of centering needed. Then a 5/16 was run through and threaded to my standard home shop size of 3/8-16.



Which makes me think that a person's "shop size" can likely be judged by their clamping kit size.... Hmmmm? 5/8 and 3/4 clamping hardware for the "big shops". 1/2 for the "almost big shops" and 3/8 for myself and the other "garage guys". And I suppose 1/4 or 5/16 for the bench top machinists...

[Bob La Londe]

I don't use the drill presses that much any more (I have four of them), but I was thinking that I might use atleast one of them for certain types of jobs (counter sinking and counter boring mostly) more often if I had a better FAST clamping setup for the drill press. My son and I made a float lock drill press vise for my dad for Christmas 2020. I think it would be very fast for those types of jobs except for the main lead screw. Its very very slow. LOL. I've been trying to come up with a quick half nut mechanism in my mind that I like and would be relative easy to do. Press the button, slide it up close, and crank the handle to tighten. Hold downs are ok I guess, but I tend to use them rarely.

[BCRider]

Bob, perhaps instead of a lead screw float lock look at the sliding and cam lock version and see if you can buy or replicate that sort. Fast an action as you could wish for. Pretty much just like you describe. I'm just not sure about how they work

Of course the float lock style is still an edge clamping style. Lots of things like plate or longer bar stock that works more nicely with a flat down clamp. And that's what led me to this thread. I've got a couple of the vise grip style hold down clamps. But they are always such a PITA to put the nut onto the end of the bolt which is just a plain end and seems to be deformed a bit so it is hard to find the start.

It just occurred to me that I might make a lower knob for it that has a reverse or female Higbee end with a counter bore that slides over the threads to ensure a gool lining up and then engages.... Oh good, another thread....

[Paul Alciatore]

Nice clamp. Some have made similar ones from pipe sections.

"Higby", I know I have heard that word before. Can't remember where or what. Does it have more than one meaning?

[djc]

"Higby", I know I have heard that word before.

1891 was a while ago, so you have a good memory. https://patents.google.com/patent/US447775A

[wierdscience]

Neat, sometimes simple is best, I bet those would work good for hold downs on a CNC router.