Harrison Milling Machine

[hermetic]

Pictures and dimensions as promised. Handle is 5" between shaft centre and handle centre and about 6" measred from the boss on the shaft to the handle boss diagonally down the shank.

[Zoot Suit]

Thanks Phil that is a big help.

Your dimensions correlate with what I measured just before I took my machine apart.

John

[Zoot Suit]

Hi folks, I haven’t been idle although it was SWMBO's birthday last weekend so not a lot done on the mill or any of my other projects however I have been cleaning stuff off during evenings after work.  I will do a proper update when I get to a reasonable milestone but in the meantime I have a question.

The cross slide is locked by a pin with a notch in it and when I took it out it seems to have been overtightened and bent and it is starting to fracture.  I will make a new one but my question is what material should I use?  Mild steel, tool steel or something else?  I was thinking something like EN8 (I think the US equivalent is AISI 1040).  What do you think?







John

[awemawson]

My money would be on EN8, a good 'machine steel' - it's not exactly under huge stress

[Zoot Suit]

Thanks Andrew.

John

[Vinny]

Not familiar with EN8 or 1040, but my go to for something like that would be 1144 Stressproof.

[EdK]

I'm also unfamiliar with 1040, although I've heard of it. Here are some characteristics of 1040:

Principal Design Features - 1040 steel has a higher (0.40%) carbon content for greater strength than the lower carbon alloys. It is hardenable by heat treatment, quench and tempering to develop 150 to 250 ksi tensile strength.
Applications - Used for crankshafts, couplings and cold headed parts.
Machinability - Machinability is good, rated at 60% that of the 1112 alloy used as a 100% machining rated steel.

Sounds like a good choice to me.  

Ed

[Zoot Suit]

Hello folks, I have made a bit of progress on the mill.  The main parts are painted, they took a bit longer than planned because I thinned the paint (Alkyd Enamel) as per the instructions, 20% thinners for spray application, and it turned out to be way too thin and I got loads of runs so i had to leave it to harden off and then flat the runs off and then paint it agin but this time at 10% thinners. In the picture it looks a bit bluer than it does in the flesh.  The colour is RAL 7000.



The small motor that drives the table is off being rewound at 230v three phase, hopefully it will be back soon.  I still need to order new thrust bearings for the various acme threaded shafts which I will do on Monday along with a few replacements for a few missing screws.  The plan is to try and get it more or less together next weekend.

I still have a couple of small parts to make and I need to sort out a crank for the knee.  It is a spline fitting but all of the cranks I have seen are a different fitting so i will have to get something of the right size and then adapt it to fit this machine.

I have a question for hermetic if you are reading this?

I fitted the knee back on today but I realised that I had not noted which clamp for locking the knee was at which side of the machine.  The user manual and parts book does not tell me either.  My question is which side does the left hand thread clamp fit, right or left?  At the moment I have the left hand thread on my left when stood in front of the machine, the same side as the knee handle.  

Here is one of the clamps that I am talking about.  This is where I have fitted the one with the right hand thread.



John

[TomG]

(06-10-2017, 03:17 PM)Zoot Suit Wrote: Hello folks, I have made a bit of progress on the mill.  The main parts are painted, they took a bit longer than planned because I thinned the paint (Alkyd Enamel) as per the instructions, 20% thinners for spray application, and it turned out to be way too thin and I got loads of runs so i had to leave it to harden off and then flat the runs off and then paint it agin but this time at 10% thinners. In the picture it looks a bit bluer than it does in the flesh.  The colour is RAL 7000.

John

It's coming along nicely, John. Alkyd enamel runs easily even when properly reduced because it dries so slowly. It does make nice machinery paint though.

Tom

[f350ca]

Nice paint job John. The amount of reducer is a fine line, too much you get runs easily, to little it won't flow and you get over spray laying on the surface. Metallic is worse.