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7” Massive Antique Prentiss Vise Help

mnlamont

Plastic
Joined
Sep 4, 2022
Hey everyone, I’m new to this forum, but appreciate any help anyone can offer me. Over the last week I picked up two Prentiss vises. One is a smaller one, has identification on it (No. 181), seems to work well, no issues with that. I got it for $35 which includes the steel cabinet it’s sitting on.

The real one that I’m wanting to talk about is this beast that I bought off someone (see the pictures). It says PV CO under the handle, is 26 inches long, not including the handle bracket (adds an addl 5”). It’s 13 inches tall, and has 7 inch wide jaws. I haven’t officially weighed it yet, but I think it’s definitely over 150 pounds. I saw off another post in this forum that it is likely a reverse jaw vise, is supposed to have a pin on top that you can pull that you can flip the jaw around. I can see where the pin is/was, it is currently ground flat. I’m assuming it was likely peened over and then ground flat. I’m hoping that I can tap it out from the bottom, but the issue is the vise is stuck shut, and it also has a crack along the tail. I’m assuming I can just vee that out and braze it, and the rust inside of it may be whats keeping the vice from opening. I was thinking about maybe doing some electrolysis to get rid of rust and then putting a torch on it to try to get it to open up for me. I appreciate anyone help anyone can offer with:

1. Identification of this beast
2. Any tips on how to try to get the jaws freed up without breaking the inner nut.
3. Have these jaws been brazed, or did they come like that?
4. Will I be able to tap that pin out? Or do I need to drill it?
4. Looks like this was a swivel vise, although someone has thrown some weld or something into the hole where it used to tighten. I’m thinking about just drilling that out and re-tapping it and fabricating something. Any other ideas?

Thanks everyone in advance!

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magneticanomaly

Titanium
Joined
Mar 22, 2007
Location
On Elk Mountain, West Virginia, USA
That was sure a nice vise once-upon-a-time. Been rode hard and put away wet, as they say around here.You will need the help of, or to become, someone expert in brazing and or welding cast iron to restore it to long-term usefulness. Thre are lots of threads here that discuss processes.
First step indeed should be to get the sliding jaw out of the body. Turn it upside-down to get a look at the screw to see why it may not want to come out. If it is heavily rusted and thus adds to the list of parts requiring a lot of work, you may decide to relinquish the vise to ornamental use only.
If screw seems likely to be stuck in nut because of only moderate rust, they electroltic de-rusting would be worth a try. But you will have to connect the negative wire to the screw itself, not to any other part of the vise because the parts may not be electrically continuous. Even with good electrical connection, electrolysis may not work well because the screw is "shadowed" inside the ram. Chemical de-rusting may be a bettter bet.
Brazing the steel jaw inserts to the badly crumbled cast-iron was a nasty bodge, and obviously not well executed. The iron should be welded or brazed-up and re-machined to fit and support the inserts properly. I would recommend brazing to ensure that the result is soft enough to re-drill and tap to properly attach the inserts with screws.
You might be able to remove the swiveling jaw pin by drilling and tapping it and improvisng a slidehammer on a threaded rod. Building the top of the pin back to we--above flush before you drill it will tend to loosen it, unless somebody has already welded it in. The swivelling jaw is significantly weaker than a solid jaw, ad an interesting challenge to fix if you break it- DAMHIKT.
Welding the crack in the ram will be pretty straightforward...but ram wil probably be a little narrower when it is done, so it will be a little looser in the housing.
 

Tom A

Hot Rolled
Joined
Apr 26, 2009
Location
NW Florida
JST is right - The pin releases the the rear jaw, so it can swivel, and hold odd shaped work. I have it's 3" baby brother vise, and it's my favorite :~)
BTW, I think the pin is tapered, so you should be able to knock it out from below.
 
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Joined
Feb 4, 2004
Location
Metuchen, NJ, USA
Pursuant to MagneticAnomaly's comment about the "shadowing" problem when applying electrolysis to the screw:

Sometimes one can make a electrolysis anode out of sheet metal to fit oddly-shaped recesses. It can be thin; it's a one-time-use deal.

Plastic window screening can be used to insulate the anode from the workpiece; the electrolysis process works right through the screen.

Good luck with this project! It's a challenge.

John Ruth
 

mnlamont

Plastic
Joined
Sep 4, 2022
Thanks everyone for all the responses, I really appreciate all the input. I have a ton of respect for old tools, it was really hard for me to see how beat up this thing was, Seriously has hammer marks all over it. Luckily, the other side of the jaws are in a little better shape. I am super motivated and dedicated to try to bring it back to life. I’m going to grind the jaws back to clean metal, and then get it brazed, and try to hand mill out the step, and then re-drill and tap for jaws. Same with the tail. I’m gonna very carefully try to get this thing opened up without ruining the nut. It may not be the tightest vice when I’m done with it, but I’m hoping to get it back in to some form of use, and after its painted and tuned up, hopefully it’ll look like a million bucks.

For anyone interested, someone posted a page out of an old catalog, I think it may be a number 23, given that it has the swivel base, the pin in the top, and 7 inch jaws. That would put it at 207 pounds, I will try to verify that soon on a scale.

On another note, anyone know how the handle fixes to the moveable jaw? There is no collar and there are no holes where it would thread into. Once I get the screw moving, I don’t see why it wouldn’t just thread out of the movable jaw.

I appreciate anyone else’s input and/or advice.FBB98642-90CC-490F-9A65-E32F631512E8.jpeg88B8F5F4-A24A-46B0-837F-1C99CCDAC7C3.jpegB4040287-D686-4119-A873-00F810ED1F18.jpeg33CFABAC-637E-4AA5-BEB5-239DD970E91C.jpeg
 

M.B. Naegle

Titanium
Joined
Feb 7, 2011
Location
Conroe, TX USA
We have a smaller Prentise in the shop with the same swivel jaw but has a fixed base. It and a couple other of our vises have the same exposed ram design that are likewise beaten and cracked. On one that is used for sheet metal work (deep jaws) I made a wood cover for the ram, as a place holder for a tin one someday, that has "NOT AN ANVIL!!!" writen on it. Wishful thinking that others take it seriously.

Our Prentiss had a make shift pin that I replaced, but I left the end cylindrical. One of my "when I get a round to it" jobs is to cut a ball into the end for cosmetics, but also to lessen the chance of someone using it as a little anvil surface.
 
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Jim Christie

Titanium
Joined
Mar 14, 2007
Location
L'Orignal, Ontario Canada
I was thinking you might want to put some socket head cap screws a cross the crack in the tail of the moving jaw to pull it together for welding if that wasn't already your plan.
Depending on the thickness at the top of the tail you could use something like 1/4" or 10-32 as in the attached picture .
Not so large as to excessively weaken the casting .
Drill the tap drill size well into the the far side of the crack and a clearance drill far enough across the crack so there is no thread on the first side that it will allow you to pull the crack together and counter bore the hole for the set cap screw so it can remain after welding.
You could put all the screws on one side or alternate them and you could remove them after drilling and tapping to allow for grinding the V for welding and then put them back in close up the crack before welding.
Be sure to leave a narrow strip of the original cracked faces at the bottom of V so when pulled together they maintain the the original width.
On my Record Vide there is a cross pin with a washer and spring that helps the screw to open the jaw .
The springs on those often get mashed when forced trying to open the vise too far and the small pin can get sheared off on both sides and remain stuck in the screw and hard to see if it's rusty .
On the Record the pin is just a piece of cold rolled steel that has been pinched in the middle and driven in tight in the cross hole as shown in the other picture.
Some others may use a roll or spring pin.
Maybe yours will be similar .
Jim
 

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Joe Michaels

Diamond
Joined
Apr 3, 2004
Location
Shandaken, NY, USA
The Prentiss vise, while as big as it gets and likely not too common, has seen too much abuse and 'cobbed together repairs' to really be worth throwing more time, effort and money at. Repairs for the vise would be quite an exercise in shop work. The fact the jaw plates and their seatings on the moveable and fixed jaws are so heavily brazed up has me thinking the vise is likely beyond any repair. While it is possible to repair the crack in the slide and get the top swivel jaw and swivel base freed up and working correctly, the vise jaws are a complete disaster area. However, seeing the photos of the old vise led me to think of how it could be repaired.

Jim Christie beat me to the punch as far as recommendations for the repair of the cracked vise slide. My thoughts are:

1. stop-drill the end of the crack to keep it from propigating.
2. Clamp across the slide to pull the crack tight together.
3. Cross drill some thru holes, diameter to be determined by thickness of the top section of the slide. I'd try for 1/4" holes, drilling at 15/64" and reaming them to final
size. Countersink the mouth of each hole on both side of the slide, as wide/deep as possible.
4. Use some W-1 or O-1 drill rod or a steel like 4140 or 4340 for pins. Cut the drill rod so it stick out beyond the sides of the slide, maybe 3/8". This is a 'heading
allowance. If going with the 4140 or 4340, try to get some turned-ground-polished (TGP) stock to save having to turn the pins to size.
5. I'd take a piece of thick flat bar and drill a blind 1/4" hole in it (equal to the amount that the drill rod projects from the sides of the slide). Clamp this piece of flatbar
to the side of the ram. This piece is a 'bucking tool'.
6. Using an oxyacetylene torch with a fairly small tip, heat the projecting end(s) of the drill rod pins to a red/orange heat. Using a ball pein hammer, peen the projecting
ends down into the countersinks to form flush rivet heads. Do one side of the slide at a time. Dress the heads off flush with the side of the ram (old timers would chip
the heads off flush with a cold chisel, then finish by filing). If an angle or die grinder is used, care must be taken to avoid putting divots into the side of the slide.
7. When the pins on the first side are riveted into the countersinked holes, clamp a piece of undrilled heavy flat bar against the rivet heads. This is a 'bucking tool'.
8. Heat the projecting ends of the pins on the second side of the slide and rivet over as per step 6. Flush off the heads as per step 6.

Hot riveting is an old time way of making this sort of repair. Done properly, the heated rivet shanks will contract on cooling and help clamp the crack together. I went with drill rod or 4140 or 4340 steel to get a higher tensile strength in the pins. The reamed fits insure the pins will make a rigid connection and prevent any motion
across the crack.

Welding: I'd vee the crack out using a die grinder and burring tool so as to follow the line of the crack. As Jim Christie notes, do not go clear thru the crack but leave about 1/8" at the bottom so the fractured edges mate together. I'd preheat the slide to a good dull red to burn out any oil. Preheating something this size can be done economically in a wood or charcoal fire rather than go thru a lot of propane or oxygen/acetylene. Putting the moveable jaw/slide into a bed of wood coals and letting it soak up the heat for at least 30 minutes would be how I'd go about the preheat. Pull the jaw/slide out of the coals and land on some firebricks and start welding the crack. I'd use a cast iron repair electrode as the composition of the slide is some type of cast iron. A nickel alloy rod that is machineable after welding is pricey, but will be worth it as it will allow finishing the weld down flush with the top of the slide. Weld in small stitches, hop-scotching along the slide. Peen each stitch as soon as it is welded. I use an air needle scaler for this peening, but laying on rapid light blows with the pointed end of a welder's slag pick will work. Build up the weld in short stitches, using a backstep technique to tie in the stitches. After welding, I'd put the jaw/slide back in the coal bed, cover with glowing wood coals, and let it sit there until the fire has died out and things cool to ambient temperature.

The fixed jaw has a swivelling top jaw. The pin to lock this swivelling top jaw parallel to the moveable jaw looks to have been broken off and peened over. There are a few ways I'd approach fixing this. One is to find apoproximate center of the pin, and start drilling down into the pin. Working up in drill sized until the pin is pretty much 'cored out', then try to collapse the pin using a cape chisel and hammer. Another method, if skilled with welding, is to weld a rod to the pin and make a 'slide hammer' on the rod. Once the pin is removed, a new pin will have to be turned from steel bar stock. Matching the taper will take a little 'cut and try' until the compound of the lathe is adjusted to the matching taper. The swivelling top jaw can be used as a gauge on the tapered pin being turned in the lathe, using chalk or Prussian Blue to check the fit of the taper.

The vise jaw plates and their seatings is a complete disaster area. Someone went for broke using a lot of brazing rod and oxygen and acetylene. Setting the vise jaws up to re-mill the seatings for the jaw plates would be quite a job. In my opinion, the condition of the vise jaws is a show stopper. I'd use that vise for the roughest work, work like holding jobs for welding. That old vise has been rode hard and put up wet, and aside from being usable for rough work, is basically a boat anchor or support for a rural mailbox.
 
Joined
Feb 4, 2004
Location
Metuchen, NJ, USA
If faced with this problem, I might try these methods. Disclaimer: All are hypothetical, as I've not done this yet.

1) Using countersunk flathead hex-recess screws, a.k.a. Flathead Allen screws. More surface area under the head than a counterbored SHCS.

2) I'd surely attack the stuck, possibly peened-over taper pin holding the swiveling rear jaw by welding something to it, just as Joe Michaels mentioned.
My first attempt would be "quick and dirty"; I'd lay a hex nut atop the pin and put the welding electrode down inside the nut and hold the arc until the nut was glowing red and filled! Let it cool, then start working on it with bigger and bigger wrenches until it either comes free or the weld breaks. ( The heat might break the rust bond holding the pin in the hole. )

After breaking that weld, I'd clean up and follow Joe's slide hammer recommendation to the letter!

Factoid: There are standard-size taper pins and standard-size taper pin reamers. See Machinery's Handbook of the appropriate vintage.

This could seriously guide your selection of drills and depths to either "core out" the pin or possibly tap it for a "puller" bolt.

3) There's a YouTube which shows a simple but ingenious way of pulling the whole moveable jaw out. ( will someday try this myself on a stuck Parker vise. )
 

Doozer

Titanium
Joined
Jul 23, 2001
Location
Buffalo NY
Q? Are you truly going to try and free up the swivel jaw ?
Do you really think you are going to use that feature ?
It is clearly rusted solidly in place.
Is the effort required to make it work again
worth the utility that this feature offers ?
If you have OCD and want to make it right
to please your brain, just realize that your
brain is making life difficult for you. Maybe
you time could be better spend trying to
figure out the cause and remedy for your
OCD condition. Not saying this applies to
you, but if it does, it might be worth some
thought.


----Doozer
 

AD Design

Stainless
Joined
Jun 27, 2012
Location
Tennessee USA
OCD? I suspect many of us here have it and not feel the need to correct it if you're driving the syndrome and the syndrome isn't driving you. Perhaps OCD has allowed many of us to excel at this demanding/exacting trade. JMO.

I have an old Prentis #10 (Coachbuilder type) I got from an old guy selling me a used riding mower. I cleaned it up, freed all the movements, and resisted the urge to make it pretty. Instead of the traditional Japanning finish I used the closest rattle can paint, the next owner can remove the finish for Japanning if they want true original restoration. I have a soft spot for old iron machinery, this is all I have room for. It's (supposedly) just over 100 years old and will return to service as soon as I can clear my woodworking bench. As someone that considers myself more of a caretaker than an owner of old things I hope it lasts another 100 years. Perhaps another generation will be glad that I did.
 

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Tom A

Hot Rolled
Joined
Apr 26, 2009
Location
NW Florida
I don't know - I use the swiveling jaw all the time on mine. In fact, I just leave the pin out, and in the tool box - The vise seems to grip firmly, automatically, no matter what shape the object is, straight or lopsided
 

Doozer

Titanium
Joined
Jul 23, 2001
Location
Buffalo NY
Very serious question, what are you clamping that is tapered?
And what is the limit of said tapered object before the item
just shoots out of the vise ? ? ?

-Doozer
 

Doozer

Titanium
Joined
Jul 23, 2001
Location
Buffalo NY
OCD? I suspect many of us here have it and not feel the need to correct it if you're driving the syndrome and the syndrome isn't driving you. Perhaps OCD has allowed many of us to excel at this demanding/exacting trade. JMO.
Very fair point. Yes, being able to turn-it-on and turn-it-off
is really the healthy place to be. I agree it allows on to excel
at many tasks. You are right on.

---D
 

Tom A

Hot Rolled
Joined
Apr 26, 2009
Location
NW Florida
Very serious question, what are you clamping that is tapered?
And what is the limit of said tapered object before the item
just shoots out of the vise ? ? ?

-Doozer
I have no idea what the limit is, as I've never clamped an evenly tapered object.
Unevenly shaped objects, or clamping something in one side of the vise, yes - The jaw swivels a little, and grips fine. Mine has the serrated jaws, which I'm sure helps.
I think that with the swiveling rear jaw, there's less of a sideways strain on the movable front jaw when clamping something uneven.
I will say that my vise is only a little 3" one, so I can't extrapolate how well a big one would work, but for what I do with it, it works.
 








 
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