Sherman gun travel lock

Adrian Harris · Post by **Adrian Harris** » Mon Aug 17, 2009 10:52 pm

Great looking part Bob. I'm sure no one would have noticed your error if you hadn't mentioned it

What's the total machining time up to now

And will you try for a second time

I spent some time on Sunday parting off 8mm stainless steel rod into the axles and radius arm pivots, and managed to break two parting tools in the process

Adrian.

Robert E Morey · Post by **Robert E Morey** » Tue Aug 18, 2009 7:36 pm

Adrian,
Ii did turn out ok, despite the near botch. Machine time is about 13 hours on each side - total 26 hours.

I may make another one if I want to cast it. I haven't decided if I want to pursue that venture. It would need to be cast in zinc-alum in order to be strong enough for actual use. White metal alone would bend I think under the weight of the barrel.

Parting stainless is a tough job. Even 303 can be difficult to work and its supposed to be the easiest of the 300 series to machine. Good luck with your next attempts!
Bob

Adrian Harris · Post by **Adrian Harris** » Tue Aug 18, 2009 7:42 pm

> total 26 hours

Crumbs. I hope you've got it away from the house and the neighbours

> Good luck with your next attempts!

Hmm, next job will be 320 track pins from 4mm bar, if it ever turns up

Adrian.

Robert E Morey · Post by **Robert E Morey** » Thu Aug 20, 2009 7:42 pm

Adrian,
The machining isn't loud or throwing chips all over <except the bench its on>. A small bench machine is quite manageable noise and swarf wise etc. I don't use coolant either so that limits the mess. My neighbors while quite close by -have never said they could hear the machine running at night.

While the 20 hour run time sounds aweful, you must remember its running while you are doing something else - even sleeping! You don't have to stand and watch it <that fascination wears off pretty fast>. It only takes about .030" (<1mm) deep cut per pass during roughing and .005 to .010 for finishing.

Tim McCarthy · Post by **Tim McCarthy** » Sat Aug 22, 2009 4:56 am

G'day Bob
Great machine work.
I have got a little CNC just learning how to use it.
What program do your run?
Any tips for a beginner?
Regards
Timbo

Adrian Harris · Post by **Adrian Harris** » Sat Aug 22, 2009 9:20 am

The noise part which worries me is the whine caused by the mill as most of these seem to run at 20k-30k rpm.

> <that fascination wears off pretty fast>

> .005 to .010 for finishing.

I can see why it's necessary to buy one with high quality mechanism and stepper motors, in order to keep to that kind of tolerance.

I have found one on Ebay which works out at about 700usd for a complete ready-to-run system, though I haven't enquired about carriage from Japan. I'm trying to generate a list of parts I would want to make to see if it would have the capacity. The biggest limitation seems to be the 11cm Z axis.

Adrian.

Robert E Morey · Post by **Robert E Morey** » Mon Aug 31, 2009 7:09 pm

Tim,
I would recommend using Mach3 for the controller, very easy to use, inexpensive, and works very well. http://www.machsupport.com/

For creating 3D programs I use Meshcam. Easy to use, inexpensive.
http://www.grzsoftware.com/

I also verify all programs before running them on the machine. I use Cutviewer Mill. Inexpensive, and easy to use. http://www.cutviewer.com/

For 2D and 2 1/2D parts I would recommend using Sheetcam or Cut2D. Both are inexpensive and easy to use.
http://www.sheetcam.com/
http://www.vectric.com/WebSite/Vectric/ ... _index.htm

All of the above programs came be downloaded and demo'd before buying. The Mach3 free download is limited to running 1000 lines of code however.

CAD models and DXF drawings can be made with any number of programs, Solidworks, Inventor, Rhino, or AutoCad.

Adrian,
That is a small amount of Z travel. I would recommend at least 200mm. Like this machine here:
http://www.taigtools.com/cmill.html

Hope this helps, let me know if I can answer any specifics.
Bob

Sven Strobbe · Post by **Sven Strobbe** » Mon Aug 31, 2009 8:28 pm

Robert

I've bin watching this topic with my eyes wide open...
I've bin looking on the net for affordable CNC machines and they are big and expensive...

Now i see what you use and i can't believe my eyes.
Its small and affordable...
As i see to what you can make with it you don't need those big monsters...
Did you import it from the states or is there an other place you can buy it...?

I'm gonna contact them to see if i can use it with metric dimensions and if they deliver to Belgium...

Really nice job you did with that machine....

Regards

Sven

Robert E Morey · Post by **Robert E Morey** » Tue Sep 01, 2009 4:46 pm

Sven,
Thanks for your comments. The Taig is a great machine, I'm sure they will ship to Belgium and world wide. I bought mine on e-bay here in the USA. For making model parts for our 1/6 tanks it is a perfect machine. I couldn't justify spending thousands of $$ on a larger machine, and software until I learned the ropes on CNC. This is the perfect machine to learn on. As for metric or inch, I believe they have both types available (lead screws in inch or mm). The machine control software (Mach3) can compensate either way however, you set it to metric or inch during set up. Also Meshcam allows you to program in metric or inch, so I don't think units of measure would be a problem. It is not that difficult to convert metric to inch and vis a vis. Don't let that stop you!

Adrian,
My spindle on Mill only goes to 10,000 rpm max (I use 5000-8000 rpm for most jobs) so noise from spindle is usually not an issue. The serated tooth belt has very quiet operation - not like large industrial CNC machines. I think the noise you are referring to comes from CNC router motors which run quite a bit faster (10K-30K rpm) since they usually cut softer materials (wood, foam, alum, etc) at higher travel rates. My wood router is extremely loud (hearing protection required) due to the high rpm.

Regards,
Bob

Sven Strobbe · Post by **Sven Strobbe** » Tue Sep 01, 2009 9:31 pm

Robert

I'm on the prawl now for one and got some info back from the company.
Metric shouldn't be a problem and the Voltage neither...
Also found a company in Germany who sells simular machines so i like it closer to home.
Now its a question of time and money.Planned a trip to Germany and Switzerland and in a few month to the states.
If there some left it will sure go in to my new gardenhouse alias TankFactory...

Mean time i keep being amazed by the stuff you make with it

Regards

Sven

Tim McCarthy · Post by **Tim McCarthy** » Wed Sep 02, 2009 10:06 am

G'day Bob,
Thanks for the info and the links.
I have had a quick look and they are very interesting.
I donâ€™t have Mac3 I have desktop CNC but the other programs should work with this as it all comes back to code. (I think)
The machining you are doing certainly is adding a lot of depth to your Sherman.

Regards
Timbo

Robert E Morey · Post by **Robert E Morey** » Wed Sep 02, 2009 6:22 pm

Tim,
Thanks for your comments, glad the links helped. Yes the machine control software will run any G-code program. You will just have to set up your post processor in the CAM software of your choice for that particular controller. The post processor will configure the program you created for whatever machine controller you want to run it on (Mach3, Fanuc, Mazak, Haas etc). Mach3 is very well supported here in the US. Most of the CAM software companies will help you create your own post processor if needed.

Sven
Thanks for your complements. Which machine in Germany did you find? I really like the Wabeco machines, but they are out of my price range. Here is the US Distributor for them:
http://www.mdaprecision.com/

Good luck guys, happy machining and tank building!

Sven Strobbe · Post by **Sven Strobbe** » Wed Sep 02, 2009 9:14 pm

Robert

You've hit the nail on the head...Wabeco is the company but as you said its a bit axpensive...
Also found this http://www.littlemachineshop.com/produc ... 1246550158

Regards

Sven