Needs Pictures: 0
Picture(s) thanks: 0
Results 1 to 12 of 12
Thread: Flattening a cast iron plate
-
6th May 2017, 08:29 PM #1GOLD MEMBER
- Join Date
- Mar 2008
- Location
- Townsville, Nth Qld
- Posts
- 4,236
Flattening a cast iron plate
Hello, I am flattening a couple of cast iron plates 63 x 200 surface dimensions. I have tried, over several hours, 80 grit W&D on glass, 80 grit of a belt sander belt on glass, and the Extra Coarse side of a DMT DuoSharp diamond plate, as used to rapidly repair damaged or real rough edge. (220 mesh, 60 mircron), without getting too far, as shown in the attached photos below
Can anyone please suggest a better way of flattening these plates, to a surface finish much the same as using 320 grit W&D?
All suggestions and ideas gratefully received
P1690269 (Large).jpg P1690270 (Large).jpgregards,
Dengy
-
6th May 2017 08:29 PM # ADSGoogle Adsense Advertisement
- Join Date
- Always
- Location
- Advertising world
- Posts
- Many
-
7th May 2017, 07:57 AM #2
Without having access to a surface grinder pretty much W&D is your only real option. One thing that might help would be a wooden carrier with a handle so you can really bear down when rubbing over the W&D. I made a surface plate a couple of decades ago using the traditional methods of filing and scraping with a reference surface but that is a whole different skill set to learn.
You could go on the Metalworking Forum and ask if someone would be willing to grind them flat but naturally there would be a cost involved; it will be much cheaper than asking a local engineering shop to do it though.
Are they for sharpening with diamond lapping pastes or something totally different?Nothing succeeds like a budgie without a beak.
-
7th May 2017, 08:06 AM #3GOLD MEMBER
- Join Date
- Mar 2008
- Location
- Townsville, Nth Qld
- Posts
- 4,236
Are they for sharpening with diamond lapping paste ?
Thanks for this reply, Chief. I use the magnetic stand from my dial gauge setup to grip the plates and it allows me to use downward pressure, although not evenly spread over the whole length of the plate.
-
9th May 2017, 04:48 PM #4GOLD MEMBER
- Join Date
- Mar 2008
- Location
- Townsville, Nth Qld
- Posts
- 4,236
Thanks for the tip about using a surface grinder. Found our local blade sharpener had one, and would flatten both sides of the cast iron plates for $15 each. He said they would have a glass finish. Looking forward to getting them done
regards,
Dengy
-
9th May 2017, 06:08 PM #5
That's an excellent outcome and sounds pretty darn cheap also. Looking forward to the photos...
Nothing succeeds like a budgie without a beak.
-
30th September 2017, 09:41 AM #6Hewer of wood
- Join Date
- Jan 2002
- Location
- Melbourne, Aus.
- Age
- 71
- Posts
- 12,746
Way to go.
If approaching that with some kind of powered setup I would rough them out on a linisher (the Sorby ProEdge in my case) or even Worksharp discs mounted on an arbour in a lathe or drill press.
Lapping can be done manually. Just takes time . I did a #8 plane base once. Loose 80 grit SiC grains on plate glass is probably the best option. That starts to work when the glass becomes abraded enough to hold the grains. Use kero for lubrication and regularly wipe off the abraded metal and broken grains.Cheers, Ern
-
30th September 2017, 09:54 AM #7Hewer of wood
- Join Date
- Jan 2002
- Location
- Melbourne, Aus.
- Age
- 71
- Posts
- 12,746
BTW one alternative to DIY cast iron plates is solid diamond plates at end of their life.
Cheers, Ern
-
30th September 2017, 12:48 PM #8
Start with 80m grit trizact belt glued to glass. This lasts longer and cuts better. Then move to a 120 grit trizact belt. After this you can use wet and dry. Wet and dry does not last long enough in the low grits to do the work you want.
Regards from Perth
DerekVisit www.inthewoodshop.com for tutorials on constructing handtools, handtool reviews, and my trials and tribulations with furniture builds.
-
30th September 2017, 02:04 PM #9Hewer of wood
- Join Date
- Jan 2002
- Location
- Melbourne, Aus.
- Age
- 71
- Posts
- 12,746
Glued sheet abrasive leads to the corners getting overworked.
When rehabbing a chisel or plane blade you can leave the bevel till last and then grind the drop-offs away.
When metal workers need a flat surface by hand they scrape or lap. They don't sand.Cheers, Ern
-
30th September 2017, 03:07 PM #10
Hi Ern
The issue with the corners is down to technique, don't you think? How one centralises down force is very important. Do not "wipe" the plate back-and-forth. I have had very good results, with no dubbing I can measure (good enough for the purpose). Certainly, scraping can bring a higher level of flatness. This may be done at the end, if needed. Do you find scraping faster than sanding?
Regards from Perth
DerekVisit www.inthewoodshop.com for tutorials on constructing handtools, handtool reviews, and my trials and tribulations with furniture builds.
-
30th September 2017, 05:40 PM #11Hewer of wood
- Join Date
- Jan 2002
- Location
- Melbourne, Aus.
- Age
- 71
- Posts
- 12,746
I never got past it I'm afraid. Tried figures of 8. It also happened with the WorkSharp discs and the ProEdge linisher but to a lesser extent. My generalisation was that the leading edge gets more abraded than the trailing. My speculation was that sheet abrasive allows some compression and some stretching and bunching - very minor but over thousands of strokes...
As for scraping, with the kind help of forum members I got kitted up to do it but ran out of motivation.Cheers, Ern
-
20th October 2017, 09:00 PM #12Novice
- Join Date
- Oct 2012
- Location
- Gosford
- Posts
- 15
Similar Threads
-
Large Cast Iron Plate - What for?
By DSEL74 in forum METALWORK FORUMReplies: 14Last Post: 28th July 2015, 12:21 PM -
BBQ cast iron plate for sharpening?
By Dengue in forum METALWORK FORUMReplies: 4Last Post: 24th August 2014, 08:33 PM -
Machining a Cast Iron back plate
By Dingo Dog in forum METALWORK FORUMReplies: 15Last Post: 16th September 2012, 07:40 PM -
Cast iron for diamond paste plate
By derekcohen in forum SHARPENINGReplies: 13Last Post: 28th April 2011, 10:22 PM