Golf Ball Caliber 1840 10" Seacoast Mortar

[Rock6.3]

My lowes has the Oatey dark thread cutting oil in gallon containers:
http://www.lowes.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10151&catalogId=10051&cId=SEARCH&productId=3553412&cm_mmc=SCE_gps-_-gps-_-gps-_-Oatey%20Gallon%20Cutting%20Oil&CAWELAID=1090662380

Lies!

Instore they had only the 16 ounce size (only one bottle in stock) and the employee looked up the store inventory number and said 'we don't carry the gallon size in this store.  The web is frequently wrong on what we carry'.

[GGaskill]

May have to order through the web site.

[Rock6.3]

Where can I find the best prices for bar stock to be used for mortar construction?

[GGaskill]

Look for drops or rems at your local machine shops or metal supplier if there is one nearby.  You want to avoid shipping if the piece is at all heavy.  But it is good to know for sure what alloy you are getting as some do not weld well (if welding is contemplated.)

[burnsb]

      Small world, Burnsb.  We had been using Mobile Oil's Mobilmet 404, a non-sulfur cutting oil having a light color, but that was a distributor substitute for the old Mobil Heavy Sulfur Dark Cutting Oil which they didn't carry anymore.  When I saw the Oakey Dark Cutting oil recently, I had to try it out.  BINGO!  This Oakey stuff smells just like the heavy sulfur cutting oil we have always used.  So what if it smokes a bit when you a turning some steel at a higher RPM.  Jeff, you have to give this stuff a try.  Now if we can only get Lowe's to carry it in Gallons, we be in business!

                        I love the smell of sulfur oil smoke in the morning.  The smell, you know that burned sulfur smell,
                                  throughout the whole shop.  Smells like..................."Industry".


Tracy

Sorry I didn't reply back sooner.
 
That's the stuff.
I used to run Acme-Gridley screw machines and they ran a thinner version of this dark sulphur oil.  By lunch time there would be a cloud of oil mist in the shop.  We had a lot of red wasps and you would see them flying along and hit the cloud.  It looked like they'd been hit by anti-aircraft fire. 
 
They'd have trouble staying in control, and then down they'd go. 
 
Probably wasn't real good for us either.
 
edit: As for the smell, I've always liked it.  Reminds me of my grandfather, he worked as a maintenance man at a GM plant.  That's what he smelled like when he came home and would hug me when I was little.
 

Thanks for the insight. Sorry I didn't reply sooner but I completely missed your post. I was using "Ace Thread Cutting Oil" which I've now read is practically useless. And the bits I was using were probably not the best, just a Walmart special. Something like 100 assorted bits in small diameters for 20 bucks. Later I did a bit of googling and saw a bunch of people saying A36 is made of everything from tin cans to leaf springs so hard spots aren't unusual.


I'm just about out of cutting oil so I'll get some of the Oatey's and see how that works.

The bits from Mall-Wart probably aren't great, but as long as they are HSS they'll do ok.  The trick is learning how to resharpen them.  I don't know where your skill level is, but if you have a bench grinder learn to resharpen them on that.  Get a drill point gage and start learning with it.  I've never liked those drill doctor things.  When you get the hang of grinding a bit you can do it without the gage and make that bit do all kinds of things. Make it cut big if you don't have the next size, sheet metal drills, deep hole drills, wood drills, aluminum.  They can all be decently done on a bench grinder.
 
Just keep a water cup at hand and keep it cool.
 
 

[armorer77]

Just a note on Drill Dr. I just bought one . It is wonderful to recut the center of a bit , not so much on the actual sharpening part . I still end up on the belt sander to get the bits to cut .    Ed

[The Jeff]

Another first for me during this project is threading. I've been putting off making the elevating screw and nut but finally I took the plunge and gave it a shot. Sorry for the lack of in progress pictures, but I got so carried away I forgot about taking them.



First I decided on 10 threads per inch, so eventually I figured out that works out to a tooth/groove width/depth of .050". I made my cutter out of of O-1 steel, heated the tip to bright orange and quenched in old motor oil. Then I attacked with a Dremel and tried to make the tooth as square and sharp as possible.



I used 12L14 for the nut and bolt because there's no need to make cutting them any harder for myself. I drilled a 7/16" hole in the nut, and then started making .005" passes with my cutter. I was honestly surprised how well it cut and pretty soon I had the nut made. Then I turned down the outside diameters and drilled 8 3/16" holes around the outside. I assume those were for handspikes or some sort of lever to turn the nut.


Next up was the bolt which gave me more trouble than the nut. I used a parting tool to cut the grooves, but I don't think my nut's teeth and grooves are exactly .050". I tried deepening the grooves of the bolt but finally realized the bolt's outside diameter was just too big. I turned it down some and now the nut threads on easily. Surprisingly my first threading operation turned out pretty good. There's a barely perceptible amount of backlash, but I'm not sure how close the teeth go to the bottom of the groove.


Next I cut a slot down the side of the bolt so a pin will prevent the bolt from turning. I blocked up a parting tool sideways until it was on the centerline of the bolt and engaged the back gear so the spindle wouldn't turn. Then I started scraping it along the side taking off no more than .003" per pass. After about 60 passes I had a pretty nice keyway.



The screw plate is 14 gauge stainless cut out on a water jet. My work gets a fair amount of stuff cut out so I stuck it in a scrap spot of an order. I think my boss is as anxious to see this mortar done as I am.

I don't know where your skill level is, but if you have a bench grinder learn to resharpen them on that.  Get a drill point gage and start learning with it.  I've never liked those drill doctor things.  When you get the hang of grinding a bit you can do it without the gage and make that bit do all kinds of things. Make it cut big if you don't have the next size, sheet metal drills, deep hole drills, wood drills, aluminum.  They can all be decently done on a bench grinder.
 
Just keep a water cup at hand and keep it cool.

My skill level is slim to none. To illustrate, a drill point gauge came with the lathe when I bought it, but I never knew what it was for. I thought it was an awkward to use protractor but never had a need for it. Anyway, I read a few tutorials on using one and got a drill bit a lot sharper than it was. You know, now I can justify spending more money making cannons because it's increasing my machining knowledge 

[Victor3]

My skill level is slim to none.

 No, not hardly. I used to teach community college machine shop classes and few 2nd year students could cut ID & OD square-form threads very well, let alone figure out a way to use a lathe as a shaper to cut a keyway.
 

You know, now I can justify spending more money making cannons because it's increasing my machining knowledge 

 You might want to get South Bend's excellent little book How to Run a Lathe. It's well worth the $8.
 
http://www.lindsaybks.com/bks/lathebk/index.html

[The Jeff]

I got the elevating screw and its bracket installed this evening. The threaded rod and square nuts are  8-32.



Drilling the holes took some care because the center 8-32 bolt is pretty close to the crosswise 1/4" bolt hole. However, I just took it slow and measured as many ways as I could.



Here it is all put together. I've left the elevating screw long until I assemble the bed again and see how it works. I think cutting it off flush with the wood while it's down as far as it can go is what I'll end up doing. Also I haven't added any sort of pin to ride in the slot to keep it from turning yet. I've got a few ideas, but I'm going to wait a while longer to see if I come up with any better ones.

My skill level is slim to none.

 No, not hardly. I used to teach community college machine shop classes and few 2nd year students could cut ID & OD square-form threads very well, let alone figure out a way to use a lathe as a shaper to cut a keyway.

Maybe it's because I haven't had any formal training, but I feel like I don't really know what I'm doing. Those threads don't conform to any standard and probably won't fit anything else in the world. I just drilled a hole that looked about the right size and dove in. If someone gave me a bolt and told me to make a nut, it would take me hours if I could figure it out at all. It's a good thing I don't rely on my lathe to feed myself because I would have starved long ago. 

You know, now I can justify spending more money making cannons because it's increasing my machining knowledge 

 You might want to get South Bend's excellent little book How to Run a Lathe. It's well worth the $8.
 
http://www.lindsaybks.com/bks/lathebk/index.html

Thanks for the book suggestion. I ordered one.

[burnsb]

My skill level is slim to none.

 No, not hardly. I used to teach community college machine shop classes and few 2nd year students could cut ID & OD square-form threads very well, let alone figure out a way to use a lathe as a shaper to cut a keyway.

Maybe it's because I haven't had any formal training, but I feel like I don't really know what I'm doing. Those threads don't conform to any standard and probably won't fit anything else in the world. I just drilled a hole that looked about the right size and dove in. If someone gave me a bolt and told me to make a nut, it would take me hours if I could figure it out at all. It's a good thing I don't rely on my lathe to feed myself because I would have starved long ago. 

You know, now I can justify spending more money making cannons because it's increasing my machining knowledge 

 You might want to get South Bend's excellent little book How to Run a Lathe. It's well worth the $8.
 
http://www.lindsaybks.com/bks/lathebk/index.html

Thanks for the book suggestion. I ordered one.

Very Nice work.   
 
I agree with Victor.  Using a cutoff as a threader is a good trick. 
 
Before the lead screw lathe was invented all bolts and nuts were hand cut and had to be used with their mate.  I imagine it was a lot like patting your head and rubbing your belly, I've never needed to do it that way and don't ever plan to try. 
 
Another book you'll want, if you don't already have one, is Machinery's Handbook. If you shop around on Amazon or Ebay you can get an older edition for a decent price (new copies are $90 now).  Has all the threading data you'll probably ever need, hardware standards, material standards etc.     

[The Jeff]

I've had a bit too many moving parts in my life for the past month to get much done with the mortar. I got some paint on it, but that's about it. I still haven't made a part to keep the elevation screw from turning, but I'll get to it eventually.





Anyway, I figured there was no better day to work on a range table than today, so I took the mortar down to the local gun range and set up on the trap range. I was using a ~11 ounce steel Fox ball for all tests. Eventually I want to make a range table for Fg and FFg for both Fox balls and golf balls in 5 grain increments. Time of flight would be nice too.

Grains FFg	Range Yards
20	34
25	54
30	66
35	83
40	99
45	128

All told I burned up 195 grains of powder, so it is cheaper for me to shoot my mortar a bit than zero my .50 muzzle loader for deer season!

[Double D]

A second kewpie for the entire well documented and well detailed project!



Great Job!!!!

[The Jeff]

A second kewpie for the entire well documented and well detailed project!

Thank you for the Kewpies! Making a build thread I'd enjoy reading was one of my goals. I've always liked perusing build threads because it helps clear up some of the mystery of the process of how these things can be made.