Cheap soft jaws for a 3 jaw chuck

[Timehunter]

Set screws were what I was thinking also.
Two on each side of each jaw.
You could even mark where the set screws hit the jaws and use a Dremel
or whatever to grind a little slot or hole to help them hold.

 

[RM-MN]

How securely do the soft jaws need to be fastened to the hard jaws? It looks like they would just stay in place with very little help...like a hole bored into them with a neodymium magnet pressed or glued into place.

 

[clevinski]

Hi, Bazmak,

John Lindo, a friend of mine in Spain, got me turned on to soft jaws a few years ago. He is such an advocate of them that he has written an article that will appear soon in Home Shop Machinist magazine. His basic approach is to buy one set of commercial soft jaws, and machine them into masters, which are mounted in the chuck. The masters include a tenon and holes for pins. From there, you can fabricate numerous aluminum jaw designs for your different requirements. The aluminum "slave" jaws can be removed and replaced on the "master" jaws as needed.

I have used these successfully for a variety of projects, including one that involved holding a .250 inch wide perimeter while I turned a taper on another part of a hand wheel. I have no idea how I would have done it without the soft jaws. The narrow perimeter was gripped on approximately 80% of its surface in a soft jaw recess.

I *think* that this article will be in the next issue of the magazine. It might be worth your taking a look. Whichever way you go, good luck with the project!

Charlie

I have wanted soft jaws on a no of occations but they are difficult/expensive to buy
and cutting the spiral teeth are beyond me.With buying the 3 myford lathes and restoring
i have collected a no accessories etc,one of which was a 5" 3 jaw chuck with no adaptor plate
and only outside jaws.I had been planning to incorporate in a box of bits and pieces with the
Myford sale. During one of my design sessions (in bed just before i fall asleep) i started toying
with the idea of fixing soft laws to the existing outside jaws. So today with the sun shining i
made a start.Dont know how it will turn out and what problems i will have,i may end up with egg on my face. The jaws are hard but can be cut with a file so i am hoping they will drill and tap
Rather than make all 3 ,i am going to make and fit 1 to see what problems i have.I am hoping
not to make too many changes to the existing jaws,so the soft jaws can just be removed from the front.Hopefully the chuck can be used with changing /removing the external jaws.Nothing to loseView attachment 102984 View attachment 102985 View attachment 102986 View attachment 102987

 

[deverett]

Many years ago there was a description in Model Engineer of making soft jaws using 3 short lengths of ali hexagon. Hole bored to clear the (hard) chuck jaws and held in place with a set screw bearing on the back of the hard jaw.

Dave
The Emerald Isle

 

[goldstar31]

Two sets of soft jaws for my Sieg C4 are due for delivery on Monday. The cost of each set is under £20

In addition, I ordered some hard beeswax sticks to mix with shellac flakes which makes a traditional engineers' glue.

Again, I'm advised that a contributing friend got his Myford soft jaws from a national tool shop - which has a depot near me.

More variations on a Theme, perhaps?

N

 

[bazmak]

After a couple of hrs in the shed.The hard jaw i removed was fairly soft and drilled/tapped easily
so finished the new soft jaw and finished it.Easy Peasy. HOWEVER when i checked the 2 remaining
original jaws they were pot hard so i had to have a rethink.I finished the other 2 soft jaws and fitted 2 clamping grubscrew
to the sides.When in use all the cutting forces are acting against the hard jaw shoulders so should be ok
however i am not 100% confident in the fixings being rigid enough.I will try to dimple the hard jaws for the
grub screws.Last resort may be to try and anneal the jaws or lay on a stitch weld.Meantime i am going in the shed
to make a chuck adaptor plate so i can fit the chuck to make the final machining.Wish me luck
Just a point to note.True soft jaws are usually made of mild steel to fit the chuck and replacing the hard jaws
with the intention of them accepting multiple machining usually for holding thin discs or machined parts accurately
Never seen them in alum.Aluminium soft jaws are usually add ons or cover protection pieces to hold softer
materials without damage,and can be simple folded shims or bolt on discs to the hard jaws

 

[goldstar31]

Am I having a 'senior moment' but I vaguely can see a Myford leaflet on colored paper- perhaps grey or blue and hexagon jaws- probably made of brass or bronze. This contradicts Baz but he's good sport
- I hope.

Anyone with an old Myford price list on 4 pages , please?

Norm

 

[bazmak]

During my short term on machining in the apprentice school i was only familiar with mild steel soft jaws
to be machined as required to suit a particular work piece.However after a couple of hours in the shed i have almost finished a chuck adaptor plt
I used whatever materials i had to hand and welded 2 pieces of flat bar together.Successful but not easy and not something i would recommend
Machining over hard welded joints plays havoc with cutting tools.Wore out 2 hacksaw blades and 2 carbide tips.Will finish tomorrow
i have dinner to cook.Roast beef and Yorkshire pudding

 

[BaronJ]

Hi Barry, Guys,

I don't envy you machining off those lumps I would use a bandsaw to cut them off, at least it would be less of an interrupted cut.

Just going back to the chuck jaws, I'm surprised that one of the jaws was soft enough to drill and tap, but the others were hard. Are they all from the same set ?

 

[bazmak]

Yes it surprised me.I checked the jaw no 1 and it was soft.Like a fool i proceeded on that
basic without checking the other 2. They were pot hard.Look to be the same set.Bit of a suprise
I hacksawed as much as i could and wore out 3 blades.Very time consuming and difficult
with severe interupted cut and facing across the weld.The steel itself was tough/hard
dont know what it is but i got 2 pieces about 400lg one of the myfords was mounted on them
Will go out in the shed later this morning and try to finish off

 

[bazmak]

Well after 3 hrs of hard work my dedicated soft jaw chuck is almost finished.Considering i had no use for this chuck
and was ready to give it away with a myford sale i am very happy with the result of all the hard work.It hasnt cost me anything
and will hopefully give me a useful dedicated soft jaw chuck.Some finishing and tidying up to do and the first use i have for it
is to hold 1 piece of a 6mm thrust washer to open up to 1/4" id with the die grinder so i can fit to the cross and compound
slides of the Myford.Attached image of a sanou chuck that would be ideal for making?fitting soft jaws to

 

[BaronJ]

Well you have certainly made a nice job of that backplate ! Those jaws are looking good too.
I bought a 5" chuck for my S7B so I could hold work larger than the original PB narrow body one can, but because it has a backplate it sticks forwards about 2.5" more and you have to be careful that the jaws when extended don't hit the bed. A 6" chuck would be a no no. Which is a pity because it looks like a nice chuck, maybe use on a rotary table.

 

[DJP]

Your next challenge will be to make multiple sets of soft jaws to cover a range of work diameters without too much additional trimming. I have a feeling that once you get that done the fun of this project will disappear. Hopefully you have a use for soft jaws in mind. For me they would sit in a drawer although always nice to have available.

Thanks for sharing the adventure.

 

[goldstar31]

An update. 2 sets of soft jaws for the SiegC4 arrived today.
Again, 2 sticks of beeswax to concoct a witches brew to stick things like sheets.

Now the question arises of whether Myford chucks have the same scroll.

Cheers

N

 

[clevinski]

Just a point to note.True soft jaws are usually made of mild steel to fit the chuck and replacing the hard jaws with the intention of them accepting multiple machining usually for holding thin discs or machined parts accurately Never seen them in alum.Aluminium soft jaws are usually add ons or cover protection pieces to hold softermaterials without damage,and can be simple folded shims or bolt on discs to the hard jaws

Hi, Basmak,

I respectfully disagree. For example, you can find aluminum soft jaws at these links: MonsterJaws, MSC, Abbott, Rovi. But each machinist should use what he is comfortable with, and certainly steel soft jaws will last longer in a production environment. For hobbyists, I personally think aluminum is less expensive, easier to machine, and quite precise unless you are making a large enough number of identical parts that wear is an issue. Just my opinion...

Having ruined a number of HSS end mills trying to machine down welds, I can see the challenge you have in machining your plate! I ended up grinding the welds down close to the surface before machining on the few projects I have done involving machining welds, and have had more success using carbide insert tooling to machine these lowered welds.

 

[DJP]

I have not found welds hard to machine when using 6013/7014 rods. Carbide tooling is required but these soft rods with iron filler coatings have not been problem.

Just an observation from my shop.

 

[clevinski]

Wow! That is some nice work, Bazmak! I wish I could weld that well...

 

[clevinski]

I have not found welds hard to machine when using 6013/7014 rods. Carbide tooling is required but these soft rods with iron filler coatings have not been problem.

Just an observation from my shop.

Hi, DJP...

In thinking about it, I think I had the most trouble with a piece of steel that had not been welded, but cut with an oxyacetylene torch. I don't know if that would make a difference or not, but the edges seemed almost hardened. I will have to try machining some future welds with carbide and check the results. Thanks for the info!

 

[bazmak]

Yes flame cutting leaves a hardened edge and is best ground before machining. These jaws will last me a lifetime
and i believe are superior to alum jaws for accuracy.Aluminiun is best for protecting delicate parts
Thes jaws will be used mainly for holding thin discs or washers or when a turned part is reversed
and accurate concentricity is required. As i said a chuck of very little value has been transformed inti
an occational very useful item.Nothing lost

 

[goldstar31]

Perhaps the old annealing in the fire and letting things cool down in the ashes might solve a lot of broken carbide tools


Cheers


Norman