Author Topic: Making a milling vice (Read 32926 times)

vtsteam · « **Reply #50 on:** August 16, 2014, 09:21:03 PM »

Norman, your vise looks like it already wants some work to do! Phil great that you can help out!

nel2lar · « **Reply #51 on:** August 17, 2014, 10:38:35 PM »

Norman
Very nice and the patients is just what is needed with home foundry's. The vice is starting to be very impressive, you have done a nice job on it all. The only thing to be cautious with would be cranking down when holding anything. The thinnest section will give first. Good looking project, good luck.
Nelson Collar

NormanV · « **Reply #52 on:** August 18, 2014, 01:19:42 PM »

Thank you for the kind comments, I think they were a little premature the casting has warped! I went to do some more work on it and found that it now rocks when placed on a flat surface. On inspection I found that I could fit a .5mm thick ruler under one corner when it is pressed down on the flat. In order to remove the slide and moving jaw I had 8 screws to remove, two of which were hidden under the moving jaw. Due to the distortion the moving jaw was tight to move, I pulled on it and it went suddenly, and bit me!

NormanV · « **Reply #53 on:** August 18, 2014, 01:29:00 PM »

I now have two choices, I could leave this casting for a while to settle and then remachine it or I could make another casting and also leave that to settle before I machine it. I think that I will make another casting anyway just in case the first one is not recoverable. Either way it will be some time before I can complete the vice.

vtsteam · « **Reply #54 on:** August 18, 2014, 02:00:22 PM »

Ouch and ouch! Sorry about the problems, Norman. I'm sure you'll have the vise working.

tom osselton · « **Reply #55 on:** August 18, 2014, 04:16:51 PM »

I didn't think aluminum would warp like that!

awemawson · « **Reply #56 on:** August 18, 2014, 04:24:16 PM »

Unlike cast iron, at least with aluminium you can apply judicious bending and it will take a slight bend without cracking - usually

vtsteam · « **Reply #57 on:** August 18, 2014, 05:25:12 PM »

I don't think I've ever had an aluminum casting warp after milling and I've got a lot on my lathe and accessories -- but I guess it can. Other than the lathe bed, and headstock, I haven't done as massive castings in general. The lathe has stayed straight, and I didn't age it before scraping.

NormanV · « **Reply #58 on:** August 18, 2014, 05:37:42 PM »

I have heard of iron castings warping and hadn't expected aluminium to be any different but went ahead with machining it anyway. My previous experience with the bed of a Gingery lathe did not result in any warping but that has better bracing than this casting. I could try bending this one to reduce the warp but I don't have the facilities to do it.
An idea has just come to mind, I will put it back in the furnace and heat it for 30 minutes, and then let it cool down in the unopened furnace. It normally takes an hour for this amount of aluminium to melt. so that should stress relieve it. It will be interesting to see if it makes a difference. At least the only cost will be the gas!

Doc · « **Reply #59 on:** August 18, 2014, 09:43:12 PM »

Most aluminum's are notorious for warping during machining. During machining you set up a surface stress and it will warp. We fight that problem all the time where I work. Some of the aluminum types are horrible and warp with even the lightest machining cut.

Beone · « **Reply #60 on:** August 18, 2014, 11:13:23 PM »

It's worth a try to stress relieve an al casting to be machined by baking it for 5 to 8 hours at 450-500 degrees
Dave

NormanV · « **Reply #61 on:** August 20, 2014, 08:14:47 AM »

I've cast it again and this time had a bit of an 'event'. As the header and riser filled to near the top the mould opened and metal started leaking out of the side. I rapidly put my foot on top and pressed down, that stopped the leak. I poured in the rest of the metal from the crucible and waited for the metal to have a chance to solidify before I removed my foot.
To my surprise I still got a good casting, there is quite a lot of contraction at the riser end but there is enough metal there to do the job.
I think that I might take Beone's advice and stress relieve the castings in the oven. Beone it might have been a good idea to specify the units when quoting a temperature. When I made my first furnace Dave Gingery suggested curing it at 400 degrees in the oven, I did not give it a thought and set the school workshop oven at 400 degrees and nearly burnt the school down 400 degrees Celsius is very hot!

Beone · « **Reply #62 on:** August 20, 2014, 05:24:58 PM »

Oh! Yeah! That's Fahrenheit if I set my wife's oven for 500 Celsius I would burn the house down!
Dave

NormanV · « **Reply #63 on:** August 22, 2014, 03:34:43 PM »

I've stress relieved both castings in my domestic oven. I had planned to leave them in for 5 hours but fell asleep so they were in the oven for nine hours. I was a bit concerned about the cost of electricity but was pleased to find that it only used £3 worth.
I'll start machining the new one tomorrow.

NormanV · « **Reply #64 on:** August 24, 2014, 02:20:31 PM »

I've now got the second casting almost to the same stage as the first one but even this warped slightly. When I took it off the mill after milling the base yesterday it sat absolutely flat on a surface plate. By this morning it had developed a slight rock, it is not a major problem as it straightens out when I clamp it down.
You may notice from this photo that I have added mounting lugs to fit the tee slots on the milling table to enable me to mount it in either direction on the mill.
Tomorrow I will start working on the lead screw that Philf kindly sent me.

Meldonmech · « **Reply #65 on:** August 25, 2014, 08:05:52 AM »

Norman it looks much better with the mounting lugs.

Cheers David

NormanV · « **Reply #66 on:** August 28, 2014, 07:02:37 AM »

This vice is nearing completion. This morning I clamped a piece of round bar in it and was pleased to see that the jaws are parallel and it clamps evenly.
But, I did learn some useful lessons today also. I wouldn't class myself as inexperienced but most of my engineering work has been with steel, cast iron and aluminium. This morning I had to machine the bronze nut for the leadscrew on my lathe. After a couple of dig-ins using my usual tool I thought that I would grind a new one with no top rake, well, it's chalk and cheese! After that I backed off the point of a drill and it went through with no grabbing. I have always been too lazy to grind separate tools, all I can say is, "what an idiot I am!"
The second lesson was not to forget to lock the slides on the milling machine if I want to prevent the cutter from digging in.
All in all a couple of useful lessons, I knew about it but had just been in too much of a hurry.

vtsteam · « **Reply #67 on:** August 28, 2014, 07:32:15 AM »

Sounds like you're coming along, Norman. Can't wait to see the finished vise at work!

NormanV · « **Reply #68 on:** August 28, 2014, 09:00:42 AM »

Taaraaah! It is complete!
I have just finished assembling it and am delighted at how smoothly it operates and firmly it clamps.
I fitted a roller thrust bearing on the screw which must help with the amount of force needed to clamp it.
The capacity of the vice is 100 x 75 x 25mm, I designed it to be 100 x 100 x 25 but the plain section on the screw prevents it from opening further. Next time I plan to make any equipment I should ensure that I have all the parts before casting any metal.
All in all it's been a great project and not too time consuming.

awemawson · « **Reply #69 on:** August 28, 2014, 10:57:26 AM »

Excellent stuff Norman - glad it's finished and working.

Now . . . what's the next project using the milling machine and vice

Arbalist · « **Reply #70 on:** August 28, 2014, 11:18:24 AM »

Nice one Norman!

NormanV · « **Reply #71 on:** August 28, 2014, 11:44:50 AM »

Thank you Andrew and Arbalist.
Andrew, I'm thinking about a rotary table, I have a very nice 30:1 worm and wheel that could be suitable.

mattinker · « **Reply #72 on:** August 28, 2014, 12:05:09 PM »

Nice project, looking forward to the rotary table!

regards, Matthew.

philf · « **Reply #73 on:** August 28, 2014, 03:04:23 PM »

Nice one Norman.

I'll see if the other LH screw has a shorter unthreaded portion when I'm home on Saturday.

I find a dividing head more use than a rotary table.

Cheers

Phil

tom osselton · « **Reply #74 on:** August 28, 2014, 03:41:27 PM »

Nice vice

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Author Topic: Making a milling vice (Read 32926 times)