Lufkin Holddowns. How Are They Used?

Yeah, they are quite useful.

I have never seen an illustration showing how to use them in any of the old tool catalogs. Just for grins I searched on Starrett's website, for 20 minutes, without finding them, until I hit the "magic" search term. Evidently "hold down" or "holddown" is not correct, but "hold-down" is! They are still available, the #54, but still no illustration of how to use them.

I know it took me a while to figure it out....
 
I guess it depends on what you call thin. I was using these yesterday on a 1/8" thick aluminum panel. I consider 1/8" pretty thin.

I think maybe down to 1/16" aluminum, these clamps would work. Thinner if it was steel.
 
I have a few sets from 2" long to the more usual 6" long. I have even used mine to hold down 1/32" thick brass sheet when helping my wife to make master models for jewelry making. You obviously don't squeeze thin material real hard. Yet,the hold downs have held the brass snugly enough to allow milling with small cutters and light cuts.

If I need more strength,I super glue the parts down,and warm them to get them loose afterwards.
 
Heres a 4 inch set in use making an obsolete master cylinder.IMG_0008.JPG Notice I have 2 sets of parallels under the part. One thick set under the part and the hold downs and a thin set to support the vice side of the hold downs b4 clamping down.
 
But,why would you use hold downs in that application? To make sure the block of aluminum was pressed down against the parallels? I do that with a few swats of a soft faced dead blow hammer,using the vise jaws to hold the work against the parallels. Seems more secure to me.
 
I have at least one pair of those things and can say that I have never used them in 50 years. About 50 years ago I vaguely remember seeing a machinist using them on a shaper set-up. In today’s world with the anglock feature, soft jaws that you can custom form and other tricks. I think the said hold downs for the vise are just fun to talk about. If I machine something thin, I super glue it down and then boil it in water after to remove. Or may use my vacuum plate, double sided tape, or my magnetic plate. Please note that all these methods are not foolproof and stuff could start to fly around, so please be careful…Good Luck, Dave.
 
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That is 4140 George. I probably could have just used the parallels. It was crucial the bores were square with the top and sides. I have had very good success with hold downs. Even with the Kurt vice parallism is hard to obtain. The two large bores connected with orifice holes bored crossways in the block. The three small holes go through to mount it. I made 3 of these and they worked great. I almost used soft jaws but the hold downs worked great
 
machinistmarty said:
That is 4140 George. I probably could have just used the parallels. It was crucial the bores were square with the top and sides. I have had very good success with hold downs. Even with the Kurt vice parallism is hard to obtain. The two large bores connected with orifice holes bored crossways in the block. The three small holes go through to mount it. I made 3 of these and they worked great. I almost used soft jaws but the hold downs worked great
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I too on occasion have had problems with the vise not holding square/parallel. And using a Kurt anglock to boot? To solve the problem, I did not have the movable jaw touching the part. Instead, I placed a piece of round stock in the horizontal position between the moveable jaw and the part. And tapped the part down with a lead hammer. After that, the problem went away…Good Luck, Dave.
 
Dave, I also have solved the problem at times by using aluminum welding rod on the movable jaw. The point of my post was to show the hold downs in use. Not to suggest that anyone use them in the manner that I did. But at no time when I used them did the parts move. Milling ,Drilling, fly cutting ,boring, or lapping. A Kurt vice is in itself an incredible piece of machinery. I am pretty much a blacksmith machinist. George is an artist. All that being said, not everyone or every shop has surface grinders etc. The entire piece was made with basic tools and the accuracy was incredible. They worked and I didnt have to take the time to make soft jaws for the job. I have made numerous bastard keys and stepped keys using hold downs. They work. Thats the only point i was trying to make. If Wrecks got something from this, Thats all that matters.
 
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