B&S #7 dead center build

[Susquatch]

Put the round stock between centers.

Alternatively if you use the compound method,... You still need two dial indicators (unless you have a DRO). The one indicator will measure your z-axis travel (position it on the bed with the point on the carriage), and the 2nd indicator also on the bed to measure the x-axis change of the compound with the point on the side of the compound. No stock is required. Change the angle on your compound until a movement of 1.000" in the z-axis, shows a 0.021" movement on your x-axis indicator.

Tip - I always like to move the saddle in the direction that increases x. Even if your compound side is smooth as glass, that results in a smoother reading on the x-axis indicator. But both do work.

You can cheat and just use the angle marks on the compound, but I usually find that they are not accurate enough for many jobs.

 

[garageguy]

Stelster and susquatch thanks for the info and tips. The dial indicator measuring x and y sound like the least amount of fuss and most accurate. I am leaning toward the compound method. Just have to make sure the stock is mounted really accurately between centers. Taper length should be about 2 7/8 in. I just need to see if I can come close to that with the compound.

 

[garageguy]

Well, I went out to the shop today and measured the compound travel and it has well over 3" so good there. I also have enough clearance at the side of the TS to operate the crank. here's where I'd like some more opinions: I will make it out of 3/4 round stock which will be about an inch longer than the finished piece. I am thinking of leaving about 3/4 of an inch straight and chucking that end in the 4 jaw, indicate it in, center drill, move it toward the TS, hold it by say 1/2" in the jaws and mount the other end on the dead center, and turn the taper. Or should I turn it between centers?

 

[Susquatch]

Well, I went out to the shop today and measured the compound travel and it has well over 3" so good there. I also have enough clearance at the side of the TS to operate the crank. here's where I'd like some more opinions: I will make it out of 3/4 round stock which will be about an inch longer than the finished piece. I am thinking of leaving about 3/4 of an inch straight and chucking that end in the 4 jaw, indicate it in, center drill, move it toward the TS, hold it by say 1/2" in the jaws and mount the other end on the dead center, and turn the taper. Or should I turn it between centers?

If I was making this part, I wouldn't worry about turning between centers or indicating on a 4jaw.

3 or 4 inches of stick out in a 3 jaw with 3/4 inch stock is not a huge problem. If it is, then I'd center drill it and add a live center in the tailstock. But I doubt it's a big deal unless you are hogging 30 to 50 thou cuts. A 10 thou pass should cut ok without the live center.

No need to dial it in either. It will become concentric after one or two passes.

 

[garageguy]

I see what you mean. Good points.

 

[140mower]

I see what you mean. Good points.

I would put the point on it ahead of the "gripping" part before you put the taper on it, or holding the taper might be a bother later....
Edit.... Then you can touch it up on the grinder to bring it back to concentric

 

[garageguy]

Fortunately I can touch both tapers up on the grinder so what I am thinking is to get both within about .002-.003 in. on the lathe.

 

[garageguy]

Well, due to all the tips from you guys, the dead center turned out great! I used the compound method, which was fast and accurate, then finished it off in the B&S grinder, and then built a test bar for the lathe. The test bar is why I needed a second dead center.One of those deals where you make a tool so you can make a tool. This is the first time I've ground anything between centers, and holy moly is this thing accurate! It really changes the way you think about how accurate you can be and how you measure things.

 

[YYCHM]

Lets see a picture of the finished center.....

 

[garageguy]

here's a pic of the finished center and grinding the test bar. Sorry I wasn't able to get a better pic. The only glitch was when I put the center into the tail stock I found some crud inside so had to carefully clean the tailstock with very fine emery cloth, then the fit was excellent. A big Thanks to all the guys who gave advise.

 

[YYCHM]

Very Nice!

 

[garageguy]

This is a great forum. I've learned A LOT here!