Repairing Startrite fence casting

[apreston]

Hi all,
My first post on this hallowed forum. I've been watching for a few weeks and picked up some fantastic tips. I've just started to tool-up, and it seems every google search I did for info on specific models ended up in this forum somewhere. I'm amazed at the wealth of info on here.

I've picked up a Startrite 275 table saw, which is in very good condition. I've stripped cleaned and reassembled the rise/tilt mechanism and it runs sweet-as-a-nut. So I reckon worth investing a bit more effort to get it all perfect. The only problem is the rip fence. The front guide was jammed on the bar, and I had to tap it out with a hammer. On closer inspection the casting is badly cracked I've tried to attach photo. That explains why it was jammed, and yes I probably did make it worse by hammering it off . So I'm looking for advice on how I might repair it. I've researched into welding cast iron on the web, and it looks do-able, if a little 'tricky'. My best bet would seem to be MIG welding with stainless wire as I have the right tools/consumables.

So, first question - has anyone tried repairing iron castings? Any advice?

Secondly - how accurate will I have to be on the repair? These saws don't seem to have any adjustments to correct any misalignment of fence, trunnion assembly and table top. There's no screw to adjust the angle of the fence, like I have seen on aftermarket designs. And the table is dowelled onto the trunnion assembly. I'm starting to wonder if everything was precision machined, or even individually machined by a very skilled fitter, such that any repair might need similar skills and machinery to get it to fit accurately again.

Thirdly - any suggestions for repainting? Where might I find some authentic Startrite green? And how did they get what looks like a deliberate orange-peel effect?

Andrew

 

[heatherw]

Could you post a picture of the fence as well? I have the Startrite Robland combination machine, and with that the casting is fixed, but there is adjustment for right angle on the fence itself, which is aluminium. The fence casting looks very similar to yours, though.

 

[wallace]

Hi Andrew I have had some success with welding cast, like you said it can be done with a mig. My only advice would be to V out the crack slightly and then pre heat the piece to 400 degrees. This reduces the thermal shock of using the mig. When welding don't try and do the whole run in one go, take it a bit at a time. Afterwards let the piece cool really slowly. The best way to weld cast is with a stick welder and nickel rods.
HTH
Mark

 

[SammyQ]

Wot Mark said. Sage advice. Little and often for the welds. Try OWWM.org for pikkies and tales of derring do in this respect.

Sam

 

[apreston]

Thanks for the replies.

heatherw - here's a photo of the complete fence assembly. There is a very small amount of play between the fence and castings, by virtue of the screw holes being a little oversize. Maybe this play is all that is needed? Actually, somebody has bashed the front end of the fence with a hammer (not me!!) so much so that it's a very tight fit on the casting- I'll need to tidy this up so that I can get the benefit of the play in the screw holes.

 

[heatherw]

Yes, I think you're right, just a little play at one end would make a lot of difference at the other end, and you have the end hook to hold it in position, I assume, mine hasn't got that and you can easily put it out of square with an overzealous movement of the timber.

 

[apreston]

Thanks Mark, I followed your advice and seem to have made a strong (if untidy) repair. It took me a while to figure out how to preheat to 400C, then I remembered that every good DIY job uses the kitchen at some point - so I put it on the gas hob for ten minutes and quite easily got it to 400 as measured with a thermocouple. It was amazing how much easier the weld was after preheat. The cold weld was very stuttering, but the preheated weld flowed very nicely. The hardest bit was waiting 24 hours hours while it cooled slowly in a bucket of sand.

Now I need to figure out how to get some green paint of the right type - perhaps hammerite would give the right finish, but they don't do a light green colour - any suggestions?

 

[wallace]

I'm not sure but good motor factors might do hammered paint. I know you can take a piece with the colour you want and they will match it. That's how I got the colour for my wadkin stuff. I just found a piece that was under a badge and they matched that colour. You can get a litre of quick dry enamel for a tenner.