Workbench Holdfast

[Timberwolf]

I too had a bit of problem with the hold fasts not holding well on a 4 in top. I roughened the shafts by carefully banging the shafts with an old pry bar and created nice dimples on the shafts. Also,someone on Etsy sells excellent pads for the hold fasts. Just requires a bit of rubbery glue. I highly recommend them.

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Make friction your friend...To increase the gripping power of holdfasts, plane irons, etc. you can just buy a small block of rosin {Amazon} and rub it on the shafts of the holdfasts or the frogs..friction will be increased many times over.. You can also buy powdered rosin....This is an old machinist trick from an old machinist..{me}..

[amtc]

Thanks for the tip. I will indeed do that. I did notice a considerable improvement when I used some sand paper. overall I am happy with the holdfast. 
..........................
Make friction your friend...To increase the gripping power of holdfasts, plane irons, etc. you can just buy a small block of rosin {Amazon} and rub it on the shafts of the holdfasts or the frogs..friction will be increased many times over.. You can also buy powdered rosin....This is an old machinist trick from an old machinist..{me}..

[Hank Knight]

I have two of the Grammercy holdfasts and two of the Veritas holdfasts from Lee Valley that Philip posted about. Use them interchangeably If I have a preference, it is for the Veritas, but they both work great. My bench top is 3" thick maple. I don't have any problem with the the shafts slipping or not holding fast (pun intended) with my bench top, but I know people with thicker tops who do. For this reason, I would recommend the Veritas. The shafts of the Veritas ones are serrated and the serrations are sharp. They grab easily and I wouldn't think they would give you any problem in a 4" thick top. If you decide to go with a smooth shaft like the Grammercy and you have problems with it slipping or not catching, you can always counterbore the hole with a 1 1/4 to 1 1/2 inch forstner from the bottom. Drill about 1" deep, leaving 3" of top thickness.
Another tip: Glue some leather pads on the business surface of the holdfasts. It gives you a little more friction on the workpiece and prevents marring. I use 1/4" thick vegetable tanned leather pads, glued on with contact cement.

[amtc]

I have two of the Grammercy holdfasts  and two of the Veritas holdfasts from Lee Valley that Philip posted about. Use them interchangeably If I have a preference, it is for the Veritas, but they both work great. My bench top is 3" thick maple. I don't have any problem with the the shafts slipping or not holding fast (pun intended) with my bench top, but I know people with thicker tops who do. For this reason, I would recommend the Veritas. The shafts of the Veritas ones are serrated and the serrations are sharp. They grab easily and I wouldn't think they would give you any problem in a 4" thick top. If you decide to go with a smooth shaft like the Grammercy and you have problems with it slipping or not catching, you can always counterbore the hole with a 1 1/4 to 1 1/2 inch forstner from the bottom. Drill about 1" deep, leaving 3" of top thickness.
Another tip: Glue some leather pads on the business surface of the holdfasts. It gives you a little more friction on the workpiece and prevents marring. I use 1/4" thick vegetable tanned leather pads, glued on with contact cement.

I have been using the Gramercy holdfasts for a couple of weeks and have been very happy with them. The reason I wanted information about holdfasts had to do with the vise decision I made with my bench. Years ago I was lucky enough to find a Emmert pattern makers vise for sale and wanted to build a bench for the vise. I also have a Record 52 1/2 and I agonized for weeks on where to install them. I ended up installing the Emmert on the end and Record on the side. The only reason I did it that way is because my shop doubles as a 2 car garage and the Emmert is a massive vise that sticks out and I didn't want my wife and kids banging bikes and stuff into the vise! By doing this I had to sacrifice not having a tail vise which I used extensively on my old bench. 

I watched some YouTube videos with guys who had Nicholson benches without vises and they had all kinds of ways to secure work to the bench. I have made a few simple jigs and along with the holdfast I have not missed my tail vise at all. I will add that some of the jigs actually hold better than a vise. Its always fun learning new ways to work. Thanks again for the information about the holdfast.