Chirpy on pouring brass

with brass alloys, if you think it's hot enough, then it really isn't, lol

[6:06 AM]
when your scooping the dross off, you should see green/yellow flames where your scooping, and a small steel rod, it should wet to it and not ball up on it

[6:06 AM]
just heat it up first to preheat it and drive off any moisture

[6:07 AM]
a steel coat hanger would work perfect for that, just stick it in the metal and stir it around very gently to make sure everything has melted, and when you pull it out, it shouldnt have anything on it except where it wetted to it

if you take a piece of aluminum wire, just a small, short section and sit it on top of the melt right before you pour, do not mix it in, just let it sit on the top of the melt as you pour.  when you pour, the aluminum will help the brass wet it's way through the mold and flow into the mold easier, and you'll end up with a white powder on the cast part, which you just brush off with a wire brush

and I'm not talking about a massive piece of aluminum wire, just a very short section, like 3/4" section of 1/8" aluminum wire at largest

yea, higher temperature is the best bet

I usually wait till every last piece is melted down into the crucible, then skim the dross and everything off of the melt, put it back into the furnace and set a timer on your phone for 10-15 mins depending on how well insulated your furnace is and how good your burner is, then go directly from the furnace to the mold(edited)

you can scoop the dross off right before you pour, but you shouldnt have much since you skimmed a few mins before, so very little to no time lost there

the second you take brass alloys out of the furnace, your on the timer and every second counts
you can try an extra 5 mins, but I usually let it heat up 10 mins
some people's furnaces/burners aren't that great, so I said 10-15 mins

https://www.a-m.de/englisch/lexikon/giesstemperatur.htm

since your using an electric furnace, that'll help
you'll want to use the thin walled temps

MartinHewitt — Today at 5:20 PM

Sounds really like I want to go up to 1200°C.(edited)

Chirpy — Today at 5:21 PM

looks like 1160 would do it

[5:21 PM]

yea, brass, the melting point and pouring temps are really far apart, and the pouring temp range is pretty small usually

[5:22 PM]

various bronzes on the other hand, the pouring temp is slightly above melting temps, and most have a pretty wide pouring range

platypus — Today at 12:51 PM

also what should I use for bronze, flux wise? every source on the internet's trying to sell me something

Chirpy — Today at 12:52 PM

nothing tbh

platypus — Today at 12:52 PM

oh that makes my life easier lol

Chirpy — Today at 12:53 PM

Ive never really used anything for bronze, but do set your burner to run a little on the rich side

[12:53 PM]

even copper, never used flux for it

Future Sliding Abrasive Saw Mods

These are mostly notes to self and may not make much sense to others.

Am making some mods to the clamping system. 

Removed the F clamps and filled the holes with plugs drilled for 3/8 bolts or rods.

Intend to make a few more toe clamps and include bolts on one or both ends to adjust them for level.

Currently the stop to determine cut position is to the right of the angle grinder.   Thinking of reversing that so I can better clamp the work. (DONE)  As is the last six inches of stock are difficult or impossible to use because it can't be clamped.  So really only need 2 clamps on the cut off side and several on the source material.  On the cut off side one clamp for the stop and one to keep the cut part from shifting.

Move the plate that holds the height adjuster from the bottom of the linear bearing to the top.  This should provide about an additional inch of travel.  Will need to make a new adjuster rod/linkage thing.  Turn down/shorten a nut to lock the rod without using up much travel. (DONE)

Need to build an adjustable fence so the final square to the blade can be done with the fence instead of the arm that the grinder slides on.  Have been thinking about his one for a while.  Screws instead of welding to prevent metal warpage.  Mayb #10 cap head socket screws.  Have a few.

Just a note to self.  Should tear down and grease the grider's head.  It sounds dry.

Attempted repair of Delta 31-695 after blue smoke.

 

This model.  Purchased new years ago.

If I recall correctly it tripped the breaker.   I think/hope the blue smoke was from the capacitor.   The motor would still turn but not come up to speed. 

The multimeter did not charge the cap and the winding look like they just left the factory.  No I did not take the meter to them.

This is an induction motor without starter windings, switch or capacitor.   

Does have a run capacitor its actually a Mallory with the same number.

Cornell-Dubilier PSU27015A

Mfr. Part #: PSU27015A
Allied Stock #: 70186362

Description

Capacitor, 270 to 324 uF, 110/125 VAC, 50 to 60 Hz, -40 C, +65 C, 10% (Max.)

Need to grab the cap and check but this is the one I found in my search history.  From Delta its $30.  The electronics parts houses charger $17 and up.

The motor is housed inside the sander body and was difficult to remove.   The motor mount pivots on a rod which is driven into holes allowing it to span the body.  One end of the rod has splines which dig into the hole to prevent it from turning.  It should be driven out from the non spline side.  Two C/Cir clips trap the motor mount in the correct position.  The are deep within and I have no idea how I am going to get them back in.

While I had it open I changed the motor bearings.  Uses 6302 ZE replaced them with 6203 RS's which I had on hand.  Used the bearing splitter to remove both bearings.  Used to brake press's 3rd cylinder to press the back cover off the rear bearing as the finish from the factory was dismal.  Did not take much.  Polished the armature bearing journals in the lathe with 600 then 800 grit wet/dry dry.  After the polish they were easy to install but still a tight fit.  The sort where you wiggle the bearing to get it to move up to a point.  Then it slides on.  One end needed a little persuasion with a pipe on the inner race but not much.  Reassembled the motor with little difficulty.

Still need to check the bearings on the roller that carry the sanding belt.  If they are good it is time to start putting it back together.

Sunday May 9 

Installed the motor.  For future reference I did not drive the rod in quite to where it is centered.  Its close but not quite.  If I have to drive it out again it needs to be driven from the side where the rod is below the surface of the case.  Putting the cir clips on was not hard using the huge needle nose pliers.  First was easy.  Positioned the 2nd one in the groove with the pliers and finished pushing it on with a T handle allen wrench.

Pulled the bearings on the driven end of the belt.  They are dry and tired.  In the left image I was attempting to pull the holder off the bearing but the bearing came off with it.  Used the arbor press to remove the bearing from the holder. On the right I got the bearing splitter behind the 17mm snap ring which positions the bearing and ruined it.  Should be able to get that locally. These bearings are the same as in the motor 6203 RS.  Will order 10 of them this time.   Have yet to remove the bearings on the other end of the belt.  Initial research indicates they are not so common.  Might have to get them in Dalhart TX at the bearing shop.

Hope the motor works when I get a new cap for it.   Will be a few weeks as I want to gather all the ELS stuff first so I can make one order to Mourser or Digikey.  Its about $15 cheaper.  

Update:

New cap did not help.  Runs the same with or without it.  Need to investigate further.  Looking grim.

Tapping fixture start of planning

 At some point I will build a tapping fixture where I can drill and tap without moving the work.  Current plan is to use this drill base.  The column is 1.81 inches.  May cast a new table with slots that match the big drill press.   Or X pattern slots.

Scratch built Acute Tool Sharpening System (Part 2)

This was left as a draft for a few days.  It should have preceded the UPDATE post by 2 days..

I have cut all the flat parts from 1/8" hot rolled on the sliding abrasive saw.
Wood Jigs or fixtures were used to cut the angles.
Wood jigs and drilling guides were used to drill the holes.

This morning I bent the bottom brackets.  They bent a bit too far.  A little time on the anvil will open them and a few blows while clamped in the vice will move them the other way.  Total adjustment.

Have top and bottom brackets cut drilled and bent for both new tables.  Now on to the links.  After that I will turn the round pressure disks and all the mild steel work will be finished but for the table top.  At that point I plan to rust blacken theses parts.

Update

Things were going fine up to when I attempted making the slot in the links for the tables.   When I made the first table I did not have this problem.  

The table on the floor standing drill press keeps tilting on its own.  Other small problems.  I will post when I get it sorted.

Tomorrow will be a wash as we are traveling out of town.   

Some furnace rules of thumb

 

dennis — Today at 9:34 AM

I recall seeing those “rules of the fingers” on “the home foundry”. What I recall is that they all relate to the bore of the furnace. One is that your exhaust needs to be between .25 and .33 of the bore. Another is your tuyere - where the burner goes - is a bit smaller than your exhaust. How much smaller - good question.
The rules are most crucial when one wants or needs maximal performance, e.g. high temperatures. (This might well explain why aluminum is easier to melt than say, bronze.)

[9:37 AM]

Another I recall is that oil wants more room than gas. Propane, say, can burn readily with an inch per side, though more is wise if you need it for your tongs. Oil wishes at least twice that.

Sliding Abrasive Saw -- was -- Radial Arm Cut Off

 There are two similar projects on youtube.

I started on mine prior to seeing either of these.  But I did borrow JSK-koubou's handle.   Mine also has depth control, can be angled, and raised for cutting parts that do not lay flat on the table..  I am guessing that when using the front brace mine is more accurate.   Mine is still under development.

Scratch built Acute Tool Sharpening System (Part 1A more tables)

I like this table enough to realize I would like one at each grinding wheel.   To speed this up I constructed the radial cut off saw.   Currently I have cut out blanks for 2 more tables.   I have also cut the arms for the parallel motion arms of the mechanism on top the table.   

Currently the table bracket strips are soaking in vinegar to remove the mill scale.

Cutting these blanks which are simple strips was a good way to help refine the radial cut off.   The next step will be to cuts the parallel motion arms and table link to length.    I plan to make a fixture to hold the table angle brackets for cutting the triangular shape.  Maybe permanently attach them to a board that can be set into the saw.  An alignment block on the board would help position it relative to the cut off wheel.  Thinking as I type here.

The blanks were lightly sanded to clean them up after the vinegar bath.  Forget the grit maybe 280.  It was something odd. A before and after shot.

All the blanks to make 2 more tables with a few spares.

Fixture to cut the angles for the bottom brackets is clamped to the work table.

 

Magnetic LED work light.

My wife ordered a pair of these and gave me one.   The magnet is quite strong and the light good.  Like the switch on the base.  It works well on this little HF drill press in the wood shop.  Going to get a few more.

Radial Arm Cut Off

 Have made some progress but kind of stopped writing about it here.   The machine is working and I am striving to improve its accuracy.   As of today cuts vary from 50 thou down to 10 on the best results.   I would like to get it consistently to 10 if possible.

For this application just say no to HF Warrior disks.   The Diablo .040 I am using give best results if the outer 3/4 inch is gone.

Have tried adding weight to the handle.   Obviously the more weight the faster it cuts.

I think the next step is to add a depth limiting wheel that rides on the work.  The idea is to make several controlled passes.  Get the entire cut to 1/4 the thickness, then 1/2, 3/4, and finish.  Something like that.  Thinking is that my worst problems are where most of the cut is done and I have to concentrate on the bridges.

Am playing with the shop vac for dust collection.   

I will try to remember to add images soon.

---------------------------------------------------------------

Been talking with Chirpy.   Rather then a wheel to limit depth I am adding a depth stop with a adjusting wheel that references the linear bearing setup.   The downside is that if the work is not parallel to the rail it will go in at an angle.  Have to work on that. -

In the image you can see the depth stop.  Still have to make a plate on top with a hole for the threaded rod. 

The adjustment wheel is an old pulley. It's bore was too large so I loctited a steel threaded bushing into its hub.  I may put it back on the lathe and make it a little more user friendly, if it works.   Still have to make a plate on top with a hole for the threaded rod. 

Center right you see black tape on the handle.  The tape holds a slug of lead to the other side of the handle.  By changing this weight one can adjust the cutting force.

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April 18




The plate spaces the angle bracket down so it clears the bumps on the bottom of the linear bearings.  It also provides a guide hole for the dept control.

I have added a removable plate to the front of the arm to increase stability.   No picture of that atm.

Here I have removed the front plate to cut a strip off a sheet of 1/8" steel longer than the travel of the grinder.  This is after I  flipped the sheet to make the 2nd cut.