Home made bench clamp

[Cherryville Chuck]

Every so often I need to be able to pin something down on my bench. I've looked on line at the holdfasts you tap into a bench dog hole with a hammer but I have never seen any for sale anywhere around here. I got to thinking that maybe an F clamp could be modified and I have a few with various things wrong with them for parts. I took an angle grinder and trimmed the bottom end of a bar down to 3/4" wide so it would go into a dog hole and then I reversed the moveable jaw around. It seems to work pretty good. I didn't torque it down that hard but the piece was tight to the bench and the bar never tried to lift up. The F clamp may be a better idea since it has more adjustment and a plastic pad that won't mar my work.

The pictures show parts from 2 different clamps. Turns out that the jaws will interchange.

[Stick486]

I like that...
handles clamping thicker/taller items a perk...

[HandyDan]

Looks like a winner to me. It can accommodate some thick materials.

[Cherryville Chuck]

I didn't measure it but it would be close to 12". A bunch of the holdfasts I looked at only had posts a little under 9" long and then the jaw curved down at least 2" and maybe 3". With 4" of post in the dog hole that means I could clamp maybe a 2 by. If I don't want to chance having the jaw mar my work that'd mean I need a wood shim under the jaw.

Bessey makes a similar hold down for just under $40 (Can) but it is meant to be used on a steel bench for welding and the pin is too short for a wood bench so you need so you need a socket adapter for another $12.50 an it's still shorter than my McGyver effort. https://www.leevalley.com/en-ca/shop/to ... YjEALw_wcB

For the 15-20 minutes of effort with an angle grinder I think it was worth it.

[Biagio]

Somewhere (perhaps at the other forum?) I saw a guy had made a simple holdfast by attaching a wooden jaw to 3/4" pipe. I made a couple with scrap bits of oak and old conduit. Work surprisingly well - you whack down on the pipe end of the wood to hold down, and whack the back of the jaw to release.
I am sure there is a practical limit to the clamping pressure, but works well for most of my needs, and costs zero. When/if they start slipping, I will replace the wooden jaw.

[Herb Stoops]

Here is a pair I made to hold wood endo. The holes on the bench top had sliding wedges to clamp things by the edges.
Herb

[Stick486]

Here is a pair I made to hold wood endo.

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STEAL.jpg

[Herb Stoops]

The pictures show parts from 2 different clamps. Turns out that the jaws will interchange.
[/quote]

Chuck, what is that fuzzy thing in the LH side of the first picture??
Herb

[Cherryville Chuck]

The pictures show parts from 2 different clamps. Turns out that the jaws will interchange.

Chuck, what is that fuzzy thing in the LH side of the first picture??
Herb
[/quote]

When the in laws moved from the property to town I inherited their two former stray cats. One has gotten particularly cuddly. That was one of the last times we saw her until this morning. She`s supposed to sleep in the shop but she followed one of us into the house without being seen and my wife found her down in the basement this morning.

That`s a good clamping system you have there. I have 4 of LV`s bench dogs and 3 of their Wonder dogs https://www.leevalley.com/en-ca/shop/to ... 88QAvD_BwE and my end vise has dog holes drilled into it`s jaw so I can clamp just about anything by the ends but up until now the only way I could pin something straight down was if it was close enough to an edge that I could put an F clamp on it.

[Cherryville Chuck]

Somewhere (perhaps at the other forum?) I saw a guy had made a simple holdfast by attaching a wooden jaw to 3/4" pipe. I made a couple with scrap bits of oak and old conduit. Work surprisingly well - you whack down on the pipe end of the wood to hold down, and whack the back of the jaw to release.
I am sure there is a practical limit to the clamping pressure, but works well for most of my needs, and costs zero. When/if they start slipping, I will replace the wooden jaw.

I mulled that idea around in my head a few times but I couldn't visualize what I`d use for a jaw. Everything I envisioned had a screw on the end which meant machining, cutting, threading, and welding. All of which I can do but are time consuming. I never considered a wooden jaw. Come to think of it, if I wanted a screw at the end I could put a threaded insert in the end of the wooden jaw too. Good ideas. Thanks.

[Nickp]

Here is a pair I made to hold wood endo. The holes on the bench top had sliding wedges to clamp things by the edges.
Herb

Now that's one creative shop hack...!

[HandyDan]

That is just cool Herb.

[Cherryville Chuck]

Here's the rest of her. Same place, different day. Her and her daughter do take care of any mice problems. She also happens to be mute. Her mouth looks like she is saying meow but no sound comes out.

[Herb Stoops]

OHHH, a real shop cat.
Herb

[Biagio]

Hi Charles, am posting a photo of the "holdfast" - not LV, to be sure, but a fraction of the price of a Gramercy (interesting math, dividing zero by $31).
It needs some improvement: either I must relieve the lower face of the jaw from about 1,5" from the front, or more likely glue on a thickish piece of leather. You cannot see it too well in the photo, but on about that thickness of workpiece, the contact is limited to the top short edge of the workpiece. Even so, I cannot dislodge the piece without some serious wiggling.
The tube is old steel electrical conduit, from the Imperial days - 3/4"

[Cherryville Chuck]

Thanks Biagio. I thought maybe it needed more wood sticking out the back to keep it from splitting but that doesn't seem to be an issue. Good point about the tip needing to protrude downward. That makes sense since you hammer it downward which would skew the angle slightly. Leather sounds like a good option. A wooden dowel could be split longways and half glued to the end too. Drill press hold downs have rounded ends like that.

I agree with you on saving money by making something out of essentially spare parts. If it works about as well as the real thing then you've saved money that can be used on things you can't make, like router bits or any number of the other tool fetishes we are victim to.

[Biagio]

If one wants a low-profile hold-down, with considerable clamping force, I have a Vise-grip that was made for the job. It came with a threaded bolt to go through the benchtop, and a threaded eye to screw on from below - not very practical. I tried a threaded insert from below, but same deal - one has to spin the Vise-grip around tediously until it sits on the bench top. So I made a gizmo to screw to the underside of the bench top, allowing one to yank on a cord or turn a lever, thus pulling back half of a captive nut. The threaded bolt can then be dropped in, the cord released, and a half or one turn settles the bolt in the nut. An eye-bolt welded to the half-nut is spring-loaded, pushing the half-nut back to the holding position. The eye is used for pulling open.

More recently I found some Milescraft fittings (round metal disks visible in the photos) to which the Vise-grip can be attached by a stub which slides into the "keyhole slot". The supplied stubs did not fit my Vise-grip - made for the Milescraft knock-off of the Kreg, so I made one to try it out. The package includes two mounting disks, two under-surface retainers (with two bolt holes), mounting bolts and different lengths of stubs, as well as a cheap Forstner bit to recess the top disk into the bench surface. I have not installed them yet, as I would like to level my benchtop first. But the holdfasts work so well, that I may not get around to it anytime soon.

I hope Roxanne does not take umbrage at my execrable welding - I don't do it often enough to get good, and only recently realised that I had the autodarkening on max, could not see what I was welding, never mind the weld pool.

[Cherryville Chuck]

I considered that type of idea too but every idea seemed too time consuming to use. Screwing anything on the under side of my bench would be worse than most since I have a rack of squares and rulers under one section and a rack of about 25 of my small clamps under the next section, making access difficult. I considered some type of expanding anchor to go in the dog holes, like some concrete fasteners, but never came up with a workable design yet. Maybe the real problem was overthinking it. My modified F clamp seems like a perfectly good solution as does your wooden jawed/ conduit clamp.

On the subject of welding, my skills improved considerably one day when I realized that what I was watching was slag and not weld. You really can't see the weld. What I try to focus on is where the tip of the rod is and use that to landmark where I am so that I can move the rod, according to it's size and the amount of heat you have the welder set to, and try to imagine where I am depositing weld and gauge where and how fast to go in order to lay a good bead down. Of course, that applies to stick welding. I've done a bit on a wire feed but not enough to coach anyone about them.

[tomp]

Somewhere, I have an article on making a bench hold-down that fits through from a squeeze clamp. Start by removing the fixed jaw by cutting it off the steel bar, Then using heat, bend the end of the steel bar to 90° - note that the short leg winds up at 90°to the moveable jaw. FInal step is to apply heat to the steel bar at the corner and turn the short leg so that it lines up with the fixed jaw, noting that there will be a "twist" in the steel bar at the corner (I use a 24" Crescent wrench that I inherited from my FIL). The advantage to this modification is that you can make the clamping capacity as large or small as you want, depending on the starting length of the clamp. I've seen a couple of "how-to" videos on YouTube showing this modification, but don't think that I bookmarked one as it's fairly simple.

[Cherryville Chuck]

I'm having trouble visualizing that Tom. Can you come up with a picture?

[tomp]

Chuck,
I can do better than that, here's one of the YouTube videos (actually the best one I've seen) showing the modification of an Irwin Quick clamp (always one sale somewhere in a 2-pack) Modifying an Irwin Quick Clamp I have to admit that his method of twisting the short end by 90° to get it parallel to the sliding jaw is much more efficient than mine so will be the method I use on the next ones that I make.

Tom

[Cherryville Chuck]

Okay, now I see what and why. That's the kind of solution you need to use if you have a thin bench top, as in maybe up to 1 1/2" thick. There's probably not enough thickness in a bench like that to get a post type clamp like mine, Biagio's, or the holdfast type to bind the post between the top edge of the bench where the clamp goes through and the opposite side on the bottom. My bench is 4" thick so I wouldn't be able to get one of that design to go down through the hole and make the turn. How thick is the bench you're using yours on?

[tomp]

I'm using on a Festool MFT so the top is 3/4" MDF. You are correct, clamps of this type won't work on thicker tops because the bend won't turn the corner. 4" - must be a real solid top. Do you have access to the underside? If so, I've seen where people take a regular F-clamp (like Jorgensen), grind out the rivet and bolt a short piece if steel bar to the hole. To install, the bar is turned parallel to the long bar, fed through the hole in the top and the short bar turned 90° so it catches the underside of the top.

[Cherryville Chuck]

The side of the bench I normally work on isn't easily accessible or not at all. I have squares and a couple of rules under part of the top and small clamps under the rest. The other side is wide open so I could pin something on the underside of it. So far it looks like that bars or rods will bind up from the torque put on them and I won't need to. That's the simplest solution so that makes it the best one if it works.

I'm glad you brought up clamps for an mft type working surface. If you don't have room for a bench you can still have one of those to work on.