Recent Posts

Pages: 1 ... 8 9 [10]
91
Composites & Plastics / Re: Resin Casting, a favour
« Last post by Joules on May 17, 2018, 01:35:22 PM »
John, I got it from an outfit in Sheffield.

http://www.mouldcraft.co.uk/shop/4572905647/mouldcraft-a3000-black-fast-cast-polyurethane-liquid-plastic-casting-resin-kit/9474394

Really like this stuff and it seems strong, be great for plastic model parts, trains and boats.
92
Project Logs / Re: Lathe build project
« Last post by NormanV on May 17, 2018, 01:29:27 PM »
Thank you for the suggestions. I don't think that it is worth my while making one of the linkages for thread following as my requirements are very rare and I am more interested in fitting it with a fine feed to save me from having to wind the handle all the time. If I have fine feed it is just a step away from thread cutting abilities. The Knaell device is enough information for me, it is practical to do it with timing belts.
I need to do some measuring and sit over a list of timing pulleys to see if I can fit it all in. I also want to incorporate a dog clutch on the end of the leadscrew, this lathe does not have half-nuts to disengage the drive.
93
Composites & Plastics / Re: Resin Casting, a favour
« Last post by John Rudd on May 17, 2018, 01:28:36 PM »
Nice job Joules.. :thumbup:

Where'd you get your resin from?
94
Composites & Plastics / Resin Casting, a favour
« Last post by Joules on May 17, 2018, 01:16:41 PM »
I have just completed a pair of MORRIS badges for a friend.  He is restoring a 1930's Morris, the badge for the grill cost a tidy sum and really too valuable to risk on the open road.  I said I would have a go casting some replicas for road use and the original can be used for shows and judging.   First job clean up the badge and mount it, in this case on some adhesive tape to seal the rear as they seem to be stamped from brass sheet.  I will be making the mould from a material called Gelflex, it's a reusable moulding material made from Vinyl.  My mould used some waste steel banding fixed with masking tape and weighed down to form the dam for the Gelflex, the stuff is poured at around 160℃ so this does some what limit it's use to items that can stand the temperature.  I managed to burn this batch hence the dark spots in the rubber, it will still work, just throw it away when done rather than remelt, and take more care next time.

Once the rubber has set remove the dam and flip the mould over.  The masking tape did its job of keeping the rubber out of the back of the badge, it's then a fairly simple job of teasing out the original.  Gelflex is self releasing and will pick up very small details and defects.  The resin I am using is a polyurethane two part, my first time with this, it's very fluid when mixed and easy to pour but you only have about 7 mins working time including mixing.  The first one I overestimated the amount needed and it over filled the mould slightly, the next pour I got the volume spot on.

The cure time is very quick, but best to leave them on a flat surface once removed from the mould to cure overnight.  Once that was done I could clean up the edges with a scalpel and clean off any residue from the Gelflex using isopropyl alcohol.  Next, outside and spray them...  OK the original is brass, the only spray I had was chrome, I figure if the paint works I can use a yellowish lacquer to seal them and give a slight chrome colour to them.  The results are OK, I could have done a better job cleaning up the castings and maybe mix up some more resin to fill small pin holes, but again, these badges are for rally use not showing.   The whole process was easy with the great benefit of the polyurethane resin having virtually no odour.  I will be using this stuff more often for short runs of plastic parts and even light duty gears as I can make the masters in aluminium.  Hope this is useful information for someone.
95
Electronics & IC Programing / Re: Harrison 140 3 phase motor information wanted.
« Last post by seadog on May 17, 2018, 11:54:32 AM »
Hi Joe, did you see my last message?
96
How do I?? / Re: Anyone Ever Shortened a Shahe DRO Scale?
« Last post by awemawson on May 17, 2018, 06:27:48 AM »
So no more procrastinating - get on with it !

I carefully measured up, and came to the conclusion that if I shortened the scale by 60 mm it would give me sufficient wiggle room to pre-set the DRO but still allow the full 9" of Thicknesser travel unimpeded.

So a simple job of unbolting the end mount, clamp it in the vice, attack it with a hack saw, make it pretty with a file, and re-fit the end mount. All unexciting and nothing to be concerned about. As others have said, the scale comprises a PCB supported by an aluminium beam to which it is bonded.

I tried to get a picture of the cross section, but it isn't the best quality photo.


So the procedure is:

a/ Fix the scale to the cast iron body of the machine with super magnets

b/ Slide the sensor head down until it's  attached magnet contacts the original machine pointer and firmly fixes both together

c/ Adjust the thickness wheel to give as near to zero thickness as possible

d/ Zero the DRO

e/ Adjust the thickness wheel to approximately the desired thickness

f/ Plane a bit of timber at this setting and measure it

g/ Slide the fixing magnets and hence the scale to give the same reading

h/ Do a trial planing to check the results.

Now with this particular DRO the setting will be retained even when powered off, so as long as you remember NOT to press the zero button and nothing else is disturbed there is no need to go through the above procedure - the machine is ready to use  :thumbup:

97
Wood & Stuff / Re: Danckaerts Mortiser Clean Up
« Last post by awemawson on May 17, 2018, 06:13:24 AM »
Opening the back of the machine up reveals that although there are counterweights built in for each of the mortise chisels there in no provision for counterbalancing the  work carriage, nor would it be an easy job to fit a weight.  :(
98
Wood & Stuff / Re: Danckaerts Mortiser Clean Up
« Last post by awemawson on May 17, 2018, 05:27:42 AM »
The Handwheel Handles arrived in today's post so I set too fitting them. Handwheels fixed using taper pins, so a simple job of knocking out the pins and pulling the handwheels off.

Then the usual centre drill, tapping drill, start the tap in the mill to make sure it's perpendicular, finish tapping at the vice. A nice bit of cast iron to work on.

Having screwed the handwheel handles onto the handwheels, then just a case of pushing them back on, re-seating the taper pins, and 'job done'

I strongly suspect that there may have once been a counter balance weight to counter act the weight of the carriage vertically, as it's a mighty lump to raise and lower  :bugeye:
99
How do I?? / Re: Turning a bearing
« Last post by Pete49 on May 16, 2018, 11:52:15 PM »
Going from what I see lathes will only be seen in museums and brains?? well maybe rent them out once more than motor functions are needed  :)
100
How do I?? / Re: Turning a bearing
« Last post by vtsteam on May 16, 2018, 09:33:52 PM »
Would there likely be enough miles on it again to ever replace the bearing, in the coming era of autonomous vehicles? And if there were that much wear, won't there still be people with lathes and brains to fix it again? Hmmmm. Maybe I shouldn't ask...... :wack:

Nice job of work!  :beer:
Pages: 1 ... 8 9 [10]