How else can I make this part?

D

Daver

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I know from reading here that there are at least 17 different ways to perform almost any operation, so here goes.

I purchased the Oscillating Steam Engine Material kit from LMS. Thought it would be my first fun (non tooling) project. I think I am almost ready to start (as soon as I get the bench straightened out - different thread) . Anyway, I was reading through the instructions and I am somewhat stuck on Performing the Cylinder bore. I do not have a 4 Jaw chuck at this time for my HF 7X10... and Its likely to be a little while before I have the money to get one.

The steps call for mounting the block in a 4 jaw and off setting the piece in one direction by 1/8" in order to bore an off center hole.

so what would be the best alternative for making the cylinder? Is there a way to offset Square stock in a 3 Jaw safely? Would I be better off drilling it with my DP? or micro Mill (assuming it will drill that deep...). I don't have a face plate, but its a lot cheaper than a 4Jaw if it would be safe to do it in some manner with a face plate...

Any other suggestions?
 
I am no expert....but Do you have a faceplate for your lathe? Couple of hold-downs and lots of indicating can get the job done.
 
For that little amount of off set you can but a thin piece of sheet metal or keystock under one jaw you will have to play with the thickness to get it right but I have done this numerous times.. Ray
 
In general, a round part can be offset in a three jaw with a shim under one jaw. But in the case of an engine block, I am envisioning a not-so-round part, and that's where 4 jaw chucks shine. A faceplate with an angle plate and a good clamp setup would probably work well too. But I have my doubts about a 3 jaw on an irregularly shaped part. You have a picture or two?
 
Why not make your own faceplate. Home Depot sells both flat and round stock. All you need to do is cut a piece of round stock and attach a piece of flat stock. You can insert the round stock in the 3 jaw chuck and voila you have a faceplate. All that is needed is to drill and tap holes for the hold downs. Now all you have to do is mount the piece to be milled and do the work, good luck.
 
Hey Daver, why not just bore it on your mini-mill? In terms of set up time and security of the work piece I would think that slapping the block in a vise and using a boring head will be a lot faster, safer and your finish will be a lot better.
 
Thanks fastback we got one in Taunton I didnt know they sold stock. Back to the post, try this an easy
way, measure and center punch the center of the bore, open the chuck, put the block in the chuck and
stab the center punch with the tail stock center put some pressure on it, now adjust chuck and shim
as necessary. Same thing on a mill old school but it works. Really should invest in a 4 jaw once mastered
use the 3 jaw for a paperweight. Also drill in low or in back gear and wrap the chuck with duck tape just
in case some shim desides to take off.
 
GK1918 said:
Really should invest in a 4 jaw once mastered
use the 3 jaw for a paperweight. Also drill in low or in back gear and wrap the chuck with duck tape just
in case some shim desides to take off.
Click to expand...

Someone told me this when I bought my 4-jaw and I thought it was a joke. I've had the 3-jaw back on the machine once, and now I use the 4-jaw for virtually everything. It takes a little longer to set up, but after some use I can get it to 0.0005" in a few minutes. I would put the 3-jaw back on if I was facing a large number of parts to length, or doing a lot of cutting off, or turning hex stock, etc., but with the 4-jaw it is just so darned easy to be more accurate.
 
No, I don't believe it is a 1:1 ratio with the shim piece. I can't remember the formula right offhand, but is would be simple to put a known shim under a jaw and measure the TIR. I looked up one example and it said a .250 shim would result in an offset of 0.1768. Ratio is probably right. None of the jaws is in it's "normal" position, so other two are not in the same place and distance from centerline with a shim under one jaw. The shimmed jaw hits first, due to the shim, and then other two only close the gap until tight, but not in normal position.

You could draw it out and see what shim it would take to get the desired offset. I've done it that way, but a formula would make it easier.
 
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