• Scam Alert. Members are reminded to NOT send money to buy anything. Don't buy things remote and have it shipped - go get it yourself, pay in person, and take your equipment with you. Scammers have burned people on this forum. Urgency, secrecy, excuses, selling for friend, newish members, FUD, are RED FLAGS. A video conference call is not adequate assurance. Face to face interactions are required. Please report suspicions to the forum admins. Stay Safe - anyone can get scammed.

"Blanchard Grinding' or surface grinding

C

calgaryguy

Chris
I've got a cast iron 'platen' from a large belt sander with a .030 worn side-to-side 'dip' in it. Nominal thickness of the casting is about .250 across the wide platen surface.

Similar to the low-looking spot in this pic

GetFile.aspx


The face with the bolt holes facing the camera is ground at a 90deg angle to the large platen surface. I assume someone would have to use this surface to clamping as the unseen edge away from the camera has no edge.

I am, of course, looking to have this done cheaply. I've been told about, and read about 'blanchard grinding' like is used for resurfacing flywheels. etc.

Anyone in the forum know a place in Calgary that might do something like this for a reasonable price? REasonable being $50 or under - similar to a flywheel grind/resurface.

My other option is to attempt to do this with a friends mill/drill and a cutter.

Some people online have 'fixed' this with JB weld and then sand it smooth after, but the repair doesnt hold up very well from what I've read
 
Picture works fine.

0.030 is a lot to grind - especially on a lightweight surface grinder. Would be fine for a big industrial grinder, but they are most likely not going to do it for the price you are comfortable with.

Better to fly cut it flat and then grind it (if required).
 
RobinHood said:
Picture works fine.

0.030 is a lot to grind - especially on a lightweight surface grinder. Would be fine for a big industrial grinder, but they are most likely not going to do it for the price you are comfortable with.

Better to fly cut it flat and then grind it (if required).
Click to expand...
Dont automotive flywheels regularly have this kind of wear? I know I've sent flywheels in for resurfacing/grinding that had alot more than .030 to get them flat again. And its usually cheap, but it admittedly has been a few years.

^^^ That is a 'blanchard grinder' from what I can gather.
 
A flywheel grinder is for flywheels. It may work if it can be fixtured though. That would be the issue. Could also be done in a lathe.
 
I’ve been following a “sharpening tools” thread on Hobby Machinist. They seem to be talking about upgrading platten’s with some form of glass for more wear resistance.
 
now that the pic loaded for me, i can see that a lathe might not be the best. What about adding a wear plate that could be changed in the future when it wears?
 
Tom Kitta said:
Mill it flat. If you want more grind it afterwards. How big is the part? I am guessing about 18 x 6 in?
Click to expand...
YEah I think thats what we'll do. Mill it flat on the mill drill and then 'stone' the surface by hand once over.

Its about the 18x6" size you guessed.
StevSmar said:
I’ve been following a “sharpening tools” thread on Hobby Machinist. They seem to be talking about upgrading platten’s with some form of glass for more wear resistance.
Click to expand...
The threads at Vintagemachinery.org says to use graphite paper of some sort on the platen and change it when it wears out. KMS seems to carry it;

www.kmstools.com

SIA 6" Wide Graphite-Canvas Backing (Per Foot)

Price per footCut to size
www.kmstools.com www.kmstools.com

I assume I'd just use some spray adhesive to attach it.
 
@StevSmar I bought graphite material to upgrade both of my 6X48 sanders. I'll be applying them in late spring. They considerably reduce friction (and therefore heat) while being a sacrificial surface that can be easily replaced. They are reputed to be long wearing, but we'll see.
 
Interesting. Never heard of that graphite material. Is the graphite embedded into a kind of cloth or is it more solid sheet? I would have thought something rigid like UHMW or G10 or some of the Kevlar based type epoxy boards would be good in this application. Obviously friction must be a big deal, the web link said the cast iron had 1/8" saddle worn. That's a lot-o-rubbin!
 
I built a 2x72 belt grinder and use it a lot. I did consider a carbon sheet or carbon clothe for static control and wear, instead I used a piece of HR steel (to be replaced when needed), so far I've worn out about 10 belts and see little wear on the platen.

Based on that I might suggest a hard coat weld to build up your platen, grind flat and you are good to go for the next 20-30 years.
 
Update

I used my neighbours RF40 mill/drill and a 3 head carbide cutter to 'flatten' one of the two platens I needed to deal with

What you cant see in the pic is 2 angle plates farthest away from the camera that the platen is bolted to. https://www.busybeetools.com/products/angle-plate-4-5in.html

total cut was .030, and @RobinHood the results were quite good. I checked for flatness with a machinist straight edge end to end and corner to corner and I couldn't detect any unexpected 'walking' of the material The last two pics show the very top edge and bottom edge corners that didnt clean up. Not concerned about these areas.

Nominal thickness remaining on the platen seems to be about ~.125 (its a casting, but .125 seems to be close)

Sander (belt anyways) runs great now.



IMG_2361.JPG

IMG_2362.JPG

IMG_2365.JPG


IMG_2366.JPG


IMG_2367.JPG
 
YYCHM said:
RF40? Lets see a few pictures of that machine please. I see a round column.
Click to expand...
Oh maybe I'm wrong. It has the number '40' on the front. I know diddly about Mill/drills.

I can say that with no power feed and taking .003-.004 cuts each pass my bloody shoulder is tired from cranking the handle.
 
You must log in or register to reply here.
Back
Top