Hold fast does not work

[LeMarechal]

Hey there,

this was not the first time I tried to built one of these easy holdfasts. But I wasn´t successfull. It doesn´t matter if I tried out mildstell or some toolsteel with or without heattreatment. There must be one big mistake that I´m always overlooking. Or the principle of this kind of holdfast doesn´t work with my anvil, because the two holes (pritchel/hardy) are to long because they are crossing the anvil to near at the body, if that make sense...?

Here two pictures of the last two styles:

I would be very pleased if anyone could enlighten me 

Greetings Sascha

[Jim Coke]

Greetings Le,

        You might try the one I designed . It will hold flat stock as well as round and square on the diagonal. I just finished a demo at my shop and most who attended when back to their shops to make one. Mild steel will work just fine. Notice the offset which allows holding long stock. Easy to make . Let me know if you have questions. 
 

Forge on and make beautiful things 

Jim

[JHCC]

LeMarechal, I second Jim's recommendation, but to answer your original question: your holdfast may simply be too small. You need enough flex to create the tension that causes the friction that holds the tool in the pritchell hole, and your holdfast may simply not have enough length to flex sufficiently. (Note how Jim's version has lots of extra length in the vertical section that allows it to flex.)

[HojPoj]

Though if you want to try and salvage what you have, I would suggest flattening the arm section (or draw it out a bit more) so that it's a bit more flexible, this may help create more of the side force necessary to hold it in place.

[pnut]

If the geometry is wrong or it doesn't have enough spring like stated above it will not create the wedging effect needed to hold it tight in the hardy or pritchel hole.

Pnu

[ThomasPowers]

There's a type I have seen knifemakers use that straddles the face with  a spring attached to the bottom that goes to the stump and a handle to grab on the top.  Make the lower section long enough you can pull up and move it off the anvil's heel for when you don't need it.

Think of an H with a bar across the top for a handle and a bar across the bottom for the spring to connect too.  The bottom of the middle bar rests on the anvils face.

For minor work I found the moving jaw of a pipe wrench as road kill, forged it to fit my anvil's hardy hole. Welded a T handle on the top and drilled a hole across the bottom to attach a spring to. It's nice in that I can orient it inline or across the face for longer work.  Something like a screen door spring will allow you to pull it up out of the hardy and rotate it 90.  A heavier spring provides more grab though.  Hmm a short piece of chain between the spring and the hole would allow both a heavier spring and the ability to rotate it---if you can pull the spring that far!

[LeMarechal]

Thank you all for your responses.

Like I wrote in my topic description above, this was not my first try.

As you wrote I believe too, that the lenght of the clamping arm must be longer for a better function. But then it's to long for my anvil.

For a better understanding here a photograph of my little anvil. It's an 160lbs anvil of what we here in germany are calling a northern germany style.

 

You can imagine that a longer holdfast may be a little bit impractical

So it may be that I have to choose an other way.

Something like Thomas suggested seems to be one option to try out. Do you have any pictures of that?

[Latticino]

I think you misunderstood the recommendation.  You need a longer section above the anvil, not below.  To create the wedging force there must be a side load on the section in the pritchel or hardy hole.  For a test, try clamping the one you made already with a 2" thick stock and see if it works better (say a hammer head...).

Here is a video showing the spring hold down:

 

[Jim Coke]

Greetings LE,

       You might try this design I made years ago,  The upright is a pipe welded to a pass through with a wedge holding it from the bottom. Than just use a simple pip clamp . This design only takes up a small amount of anvil surface.

Forge on and make beautiful things 

Jim

 

[HojPoj]

3 hours ago, LeMarechal said:

As you wrote I believe too, that the lenght of the clamping arm must be longer for a better function. But then it's to long for my anvil.

Mine is a 66 lb version of what you have, I am aware of the space limitations.  It may just be that your current ones are too stiff at the top, hence the suggestion to thin the arm out a bit.  I made mine from something that was 5/8 inch Diameter for a 3/4 inch hole, and when it sticks I pick the anvil and stand up by it... it occasionally it doesn't stick and has to be smacked a few times before it works.

[Eventlessbox]

Perhaps a chain hold instead. Attach a chain to the far side of your stand and attach a foot loop to the other end. Measure so that when draped over the anvil the loop is about an inch above the ground. The piece you are working goes under the chain and you apply pressure with your foot in the loop.

Chain is relatively inexpensive. And the foot hold is an easy forge.

[JHCC]

A weight works too, and you've got more freedom to move around when you're not holding the loop with your foot.

[Mr Moose]

I use more of a foot lever.

[Eventlessbox]

Woo. Love pictures. Didn't even think of bike style chain. Glad I havent made mine yet. 

Mr.Moose. Is that a Kanca?

[jlpservicesinc]

so with this type of anvil the holes have to much mass around them (distance face to bottom) for the holdfast to cant and lock into place.

I have found the rod diameter can be just a little less than the hole diameter. (call it a slip fit).

the arm can be slightly longer but be sure the rod in the hole goes through the hole all the way so it can be knocked back up to loosen it. 

they won't loosen by hitting them back to center as they are all ready centered.  Sometimes there is no hammering needed. Just slide it down and it will from the weight hold just fine. 

This is the only problem I have found with North or south german pattern anvils with the wide body to face distance. 

[Mr Moose]

Eventlessbox, Yes , it is a 50 Kg Kanka. I have had it for about 1 year. It has served me well. 

[LeMarechal]

Much, much thanks to all for all the ideas...

I will play a little bit with the length of the arm and its "springiness" .... if I got a moment or so. If I got further findings... I´ll be back here, with photos :)

[Frosty]

The vertical shaft can be lengthened ABOVE the anvil to provide the spring to lock it in place. Note Jim's hold fast has both a long arm and shaft.  Another thing I've found is the diameter of the stock shouldn't be very close to the dia of the pritchel hole or it doesn't cock and lock as well. 

The pritchel hole in my Soderfors is a bit larger than 5/8" and 1/2" round doesn't made a good hold fact, 1/2" square on the other hand works just fine. I can get away with a shorter height but the heel is thin. When I needed a strong hold fast I had to make the shaft or arm longer to make 9/16" rnd. coil spring lock in. 

I made this one to hold spikes close to the hardy hole and clear the heads.

Frosty The Lucky.

[Eventlessbox]

Mr. Moose. I have the same. Been forging on it for a bit over a month now and love mine to death.

[jlpservicesinc]

On 11/5/2019 at 3:23 PM, LeMarechal said:

I will play a little bit with the length of the arm and its "springiness" .... if I got a moment or so. If I got further findings... I´ll be back here, with photos 

the length of the arm is not the key.  the key is the size to the hole.  Unlike the anvil Frosty shown which has a thin heel section which the hold fast can cant or move off to one side. 

ON a thick waisted anvil like a german or swedish anvil the waist is to thick to cant so it will not lock in place no matter how long it gets.. 

The shank size needs to be a slip fit and then it will bind in the hole when in use. But its more of a weight thing then a locked in kind of thing. 

the chain ones are a better way to go on this type of anvil. 

I experimented and with the Peddinghaus the slip fit was the only one that came close to working.  On the old London patterns they didn't care and the 5/8" round worked on every anvil that had a pritchel hole that size and over and it worked just as well in the hardie hole. 

Again because of the thickness in the waist  I did not have much of any luck with the traditional design hold down or Dog. 

[pnut]

There's an episode of The Woodwrights Shop titled, "Forging the holdfast" that explains what makes a holdfast work. You may want to do a quick search and watch it. It shows a Roubeax plate that demonstrates the "cocking" of the long arm of the holdfast in the bench. 

Pnut

[jlpservicesinc]

  LOL..    I certainly don't have any experience.. I just watch a bunch of youtube videos and merely repeat what everyone else is saying..  It's more fun that way.  

[pnut]

Jlpservices, I'm confused I didn't mention experience. I think you misunderstood who I was replying to. The you I was replying to was the op. I should have quoted some text but since it wasn't answering anything directly I didn't .   I just happened to be watching this very episode of Woodwrights Shop this morning and thought the op who I was replying to or anyone else that hasn't seen it for that matter may like to watch it.  I certainly wasn't insinuating or stating one way or the other about the validity of the advice given or experience of anyone else . Stating the op's name or quoting some text would have made it clear I wasn't trying to give the impression I was trying to discount , diminish, or contradict anyone. I was simply trying to add what I thought would be an if not educational at least entertaining avenue for someone to see Peter Ross and Roy Underhill forge a couple holdfasts because frequently people don't understand text as clearly as video and nothing more.

Pnut

Edited November 9, 2019 by pnut

[jlpservicesinc]

Not a direct response to your comment as there were no quotes. 

It was kind of a side joke..  wisdom vs smart thing.  I have been told I am not funny with jokes, but slap stick I do all right. 

I thought the videos mentioned were great.  There are actually a few of them on the subject and for sure applicable to the information. 

 

 

[pnut]

I reread my post and it looked like I was responding directly to your post above mine. I try to clear up misunderstandings like that as soon as possible. It's the one thing about communicating this way I don't like. You can't see who I'm talking to and vice versa. No harm done and I feel better about it.  Take it easy.

Pnut