more flea market finds with questions

[chucketn]

I found a few things at my local flea market today and need help identifying some of them. The first is a large pin type chuck that was on a wooden handle. The handle was shattered so I removed it. It’s marked Bridgeport H.M Corp., Made in USA. In the chuck was the chisel like tool in the second picture.
I bought it because I thought it could be used as a tap chuck for the mill or lathe. What is it, really?
Next is a General/MG 0-1” mic and spanner. The spanner is a miniature pin type that fits a threaded sleve in the barrel. The mic needs adjustment as 0 is .025 to the left of the graduation 0 on the barrel. I’ve played with it as I might use it for a micrometer stop. The spanner from my Starrett mic fits it,but how do I move zero that far?
Next is what I think is an arm for a dial indicator. It was in the same junk box as the mic and pin vise above.
The shaft has a half ball on the clamp end, and the otherend has been butchered up on a grinder. It is also bent. What did the end opposite the clamp look like originally? I think I’ll clean the rough end up inthe lathe after trying to straighten it. If I can’t make it straight, I’ll make another.
Last is a MT3 drill, 7/8”. The drill looks unused unless it was professionally sharpened, but the taper is rough as a corncob. My question here is it worth trying to skim the MT3 to clean it up, turn the MT3 down to MT2, or should I turn it to a strait shank?
Thanks for looking.
Chuck

 

[Woodster]

The Mic looks OK, just turn the barrel with your starret spanner to line up with 0 on the thimble, the check/calibrate with a slip (Gauge block). The provided spanner is for tightening/slackening the thread.
The MT3 looks perfectly serviceable. Just stone off any high points. It does not look new or professionally ground as the angle looks wrong. Should be 118deg inc.

 

[chucketn]

I've tried to line up zero, Woodster. The closest I can get it now is .025 to the left. If I close the mic, I turn it .025 by the barel graduations before the zero on the scale lines up. Hope that makes sense.

Chuck

 

[Wizard69]

I believe that ball end thing is an attachment for a dial indicator. The idea being that the long shaft fits into places you can't go with a normal dial indicator. The result is un calibrated relative indication of displacement.

The morse taper drill looks perfectly good to me. Regrinding the taper may work but I suspect it will take a bit more work than you may be ready for.

 

[chucketn]

On the MT3 drill. I plan to just skim it in my lathe to clean the taper, it's really rough looking to me. I don't have any prussian blue or anything else to check fit. It looks like it was used for a hammer or beaten with a ball pein. Lots of little dents in it.
I suspected as much on the indicator arm. Anyone know anything about the Bridgeport chuck?

Chuck

 

[chucketn]

Spent last evening playing with the General mic. Got it close to zero, but not perfect. I'll check it today against my gage block set and see if it's accurate.
Any ideas on fixing the indicator bar? How do I straighten it or do I need to? Did the end of the bar away from the indicator have a ball end on it originally?

Chuck

 

[deverett]

I believe that ball end thing is an attachment for a dial indicator. The idea being that the long shaft fits into places you can't go with a normal dial indicator. The result is un calibrated relative indication of displacement.

I agree with Wizard - I have one made by Starrett and do use it occasionally to get into places where direct contact cannot be made with the probe of a DTI.

The ring fits on the stem of the DTI, the screw keeping it in place. The short ball end probably has a flat (not obvious in your picture) and this bears against the probe of the DTI. The other end - mine has a small ball tip - bears against the item you want to measure the deflection of. It is best to preload the DTI before using this attachment.

I'm away from home at the moment, but can rig up mine and take a picture when I get home if you need a clearer explanation.

Dave
The Emerald Isle

 

[chucketn]

Thanks, Dave. I would appreciate a picture.
Chuck

 

[bazmak]

The drill looks to have been ground at 90 to use as a countersink
I have done this on a regular basis,mainly for small hard to reach csunk holes
MT will clean up with a diamond file and wet/dry

 

[deverett]

Chuck

Here's some pictures of my right angle DTI adapter:


DTI right angle accessory probe

Both ends are of equal length, which means that any deflection seen by the small ball would indicate on the DTI as if it were in direct contact. The arm is shown at maximum deflection. Note the flat on the part that bears against the DTI probe. If yours does not have that flat, it would be better if you used an elephant's foot probe on your DTI. You could get a bronze ball, drill a hole and Loctite it to the outboard arm - better than trying to use yours as it is.


Mounted on DTI. Note 1/2 rev preloading of DTI


Hastily rigged demo to show typical use. Ignore the overhanging chuck jaws!

Dave
The Emerald Isle

 

[chucketn]

Thanks Dave. The rod on mine will need straightening, a clean taper turned on the end, as well as a ball on the probe end. Mine does indeed have the flat spot on the indicator end.
Chuck

 

[Krutch]

You might find the indicator attachment, sans ball, useful in centering a center drill or drilled point in a work piece being held in a four jaw lathe chuck. With the point in the center adjust until the indicator needle quits wiggling. Straighten the bend out first!
The tiny drill chuck is similar to what I use for tiny drilling jobs. It may not be as accurate as you'd want it to be.

Krutch

 

[chucketn]

Thanks for the input, Krutch.

Chuck