Gallery, Projects and General > How do I??

How square is it? And or Where do you start?

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SPiN Racing:
WOW very nice posts.

Im happy to see a ton of that sounds exactly like what I have been doing.

Only thing I think Im really missing.. is the parallels. I am now seeing them in Pics.. now that I know what they are.. and what they are FOR... I think Im gonna have to buy a set.

I have a HUGE honking great brigdeport Vise that I have bolted down to the mill table.. and the head is trammed to the table.. but Im gonna go out in the garage and verify that the head and vice are parallel.
Using the vice with parallels is so simple. I never thought of it. I have been putting things in the vice and spending tons of time getting them square by hand. A complete bear. (Loosen, adjust SLIGHTLY...tighten.. measure... loosen.. adjust slightly.. tighten... measure... Loosen.. adjust too far.. cuss.. start over.

The lathe solution I ahve done on several occations.. just put it as close as I can.. face it.. then flip it and repeat.

I think Im also going to have to get a machinists square. Something so simple I dont have in small size. Mine is a carpenters square. /duck


OK been working and in the house all weekend.. time to go make metal shavings fly LOL


Scott

Bernd:
Scott,

Stew has done a nice job of describing machining a simular part as I did. Here's the link to that thread.
http://madmodder.net/index.php?topic=547.45

Both called slide valves. These are simular to the function of a valve in an internal combustion engine. But one valve will take care of both exhust and intake.

I bet your going to ask how they work. I'll see if I can find a link for you to look at.

Now about those parallels you just discovered. Here's is a pic of a set I was given.


They range in size form 1/2" to 1 5/8". I can't remember if it was here or the HMEM forum were somebody asked if they made metric sizes. Believe it or not they are also makered in meteric. 12MM for the 1/2" and 41mm for the 1 5/8" one. There are 10 sets of parallels in this set or 20 all together. They are/were made by Brown & Sharpe.

I think if I ever was to replace these with the exact same set it would cost me dearly.

Questions?  :)

Bernd

Rog02:
Bernd:

I have a couple of those sets except mine are old enough to be in the wood box.  I would hate to think what B&S wants for them these days.  Mine were a dumpster find when a major appliance manufacturer shut down their operation here and shipped all the jobs overseas.  They tossed all the tool room stuff in the dumpsters which in turn was scavenged by the few remaining plant maintenance guys that were closing down the plant. 

Spin:
An old trick is to use a rubber band to hold the parallels in position against the vise jaws.  The band just keeps the parallel from slipping cock-eyed as the vise is closed.  Once the vice is trammed correctly in all three axis and the parallels are in place all you have to do is snug the work in the vice and tap it down with a "thumper".  Check after final tightening all is good.  Cuts down set up time by a bunch and the repeatability is good.   

Another trick is to make some of your own "Sacrificial" parallels from aluminum.  Pretty simple job actually, just clamp a couple of strips of aluminum in the vice and make a square pass on one edge, then flip the strips over and make a parallel cut on the other side with the strips resting on the vice bottom.  The aluminum will not destroy you mills should you crash into them and if you do you haven't destroyed a expensive parallel.  The accuracy is good enough for most daily jobs and you can always drag out the good stuff for those space shuttle parts.

bogstandard:
Scott,

I grieves me to hear how you are struggling with a lack of basic items, it is a shame you don't live in the UK, I could most probably have kitted you out with my end of year clearouts.

Things like square toolsteel for use on the lathe can be used as basic parallels, as can the larger ranges of ball races, just need a matched pair, one for each end of the part in the vice. Almost anything of reasonable accuracy can be used in the early stages of machining. Later, when you want to get more tighter tolerances and with gained experience you will then know exactly what sort and size of parallels you require.

I tend to buy the cheaper chinese variety, and they do me well for my methods of machining, they may not be as accurate as some very expensive sets you see, but 0.0002" is close enough for me. I also have the advantage I can grind the surfaces of mine to get them perfect if needs be, but only very rarely does that have to be done.

If you get your vice fixed jaw running perfectly parallel to the head, and the base inside the jaws totally level (by using shims under the vice), then with a decent lump to use as a parallel, you will start to get good and repeatable parts.
I did a write up on this site which explains everything I did to true up my mill. Some of it might or might not be relevent to your setup, but the bit on the vice and the follow up posts by other people should get you on the straight and narrow. They mention about soft jaws etc.

http://www.homemodelenginemachinist.com/index.php?topic=2641.0

Bogs

SPiN Racing:
Thanks guys.

I do appereciate it.

I was out there tonight milling on this lump of aluminum that is really odd. Its in a stair shape, with tapped holes for AN fittings. It mounts to a frame rail in a curved section under the car.

It was a real bear trying to do some basic milling with the vice only.
I didnt want to kick the head over in a 45 degree angle to make a cut along the edge of the part. It doesnt make sense to spend 20 minutes kicking the head to the side.. just to make a 30 second cut that doesnt matter much.. and then 30 minutes getting the head square again.

I am getting there slowly.
As we all know.. money is tight.. so I get tools a little at a time.

parallels and a square are the next purchase... Oh and a draw bar. I wondered why the draw bar was tight. It would spin freely, then a snug of it like a friend the machinist/hacker (I now realise) said to do.. and when taking it off.. sometimes it was tough to undo. SOOO I pulled it out.. adn the threads are all galled up, and appear stretched. SOmeone laid into the thing at some point I thnik.. and must have really messed them up. ALso the top of the nut(?) is all mushroomed over. SO its time to replace it... I think they are 19 bucks from Wholesale Tool.


The only machinists I know.. one owns a CNC machine shop that went away.. and he HATES manual machines.
The other one has some really old machines that are really nice. One is a HUGE honking Mauser.. I think it has like 24 or 36" swing.. or.. wait.. The chuck is HUGE. I think thats the 24 or 36 part. He can turn rims on it.

He is.. very very smart. I mean. He is likely the smartest person I have ever met. (Father is a retired Colonel.. so I have met some theoretically smart people). Thing is.. he is soooooo intelligent that he cant even LOOK at something without smashing the whole concept to ashes.

FOr example.. Lets say I need to machine an adapter for a transmission to a different engine.
He would not say.. Oh yes.. do A B C X Y Z.... he would say that an adapter is crap.. and you ened to make a bellhousing from scratch.. But realistically the whole transmission idea is junk. What you neeed to do is make a Constant Velocity transmission to replace it. Because the regular transmission is too inefficient. And then start grabbing parts and paper to draw it up. And will not ever ever ever... help with the adapter.

I told him about the ball turner.. and he went on for 30 minutes how it wont work, and is horribly inefficient.  Of course many many of us already know the design works fine.


SO yes.

I read the posts here.. and put them in my brain and let them percolate.

I actually made a cup from pink plastic tonight, before dinner, using my boring bars. Had some left over bushing material.. so I spun it up and gave it to my wife. She gave me the eyebrow.. and then said.. Thats nice honey. /shrug
Hadnt used them yet, so wanted to see how things go. Now I know :)

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