Scraping in a straight edge

[Mill Lee farm]

It will be my honor to help you learn to scrape Rabler as I have several members here on Hobby Machinist I have taught to scrape. I will be driving out to Mechanicsburg, PA in the upcoming months to teach a class for DIPEC (US military machine rebuilding depot) to another class of their Apprentices. I have taught all there Journeymen to scrape over the last 30 years) and I can swing by your shop in Indiana to show you. You can buy me dinner ..

Maintenance Services

New Cumberland Navy Depot?!?
Mr. King, that is 45 minutes away from me in Shippensburg
Can >I< buy you dinner???

(I also didn't know DLA had a maintenance department of this caliber! I just know them for supplying us (slowly/never ) parts at our depot LOL)

 

[Richard King 2]

Not to make this a sales pitch, but if anyone wants a book, order it from me here and I'll give a forum discount. eBay charges more now then they used to.

 

[DAM 79]

That looks good on the blade radius. Hold the scraper up + in back or stand on a riser block so your handle is about 20 degrees to the table. You will get a smaller or thinner cut the higher the back is, wider the lower the back is. It looks like who ever milled the SE they head was crooked or not swept in. It happens as one of my famous students forget to sweep his mill head in and made the middle low. (Keith Rucker) Once you get one side touching all the way along the edge you can stop scraping that side and only scrape the other side and tip scrape in the SE. A trick to the trade. Less scraping mean not so sore arms....lol...you also need to buy or make a pad on the wood handle end. Many buy a rubber sanding disk and screw it to the end. Others turn a round wood handle. I'll look for a picture. Pic L to R - 1) A student who took a class in Easton MD showing an adjustable or telescopic plastic tube handle witha rubber pad on the end. He mounted a Sanvik hanle into the other end. 2) a MIT Boston class member bump scraping with his hand on a rubber pad, he is using a magnifier light to see better 3) MIT class again student is using his upper body to body scrape his practice piece. All were using carbide blades.

Easton Maryland that looks like it is at tuckahoe machine shop . Do you think you will hold another class there at some I would definitely be interested in attending?!

 

[Richard King 2]

I have a few lathes where I want to clean up the cross slide and compound, so I figured I start by making a straight edge. Got this casting from dgfoster a couple years ago. Just getting around to this, milled the faces, and just started scraping. Of course it would be nice if I had a suitable surface grinder that worked, but that's another restoration project yet to be tackled. The bottom was milled on the horizontal part of my Grizzly horizontal/vertical mill. The angle face was milled on the K&T 3k vertical with a 6" face mill. The K&T definitely left a flatter face.

I suppose if I'm going to a lot of this I'll have to invest in a power scraper. Obviously the biax are the only real name in the game but I can see trying out a demolition saw conversion before dropping the $2k+ on a biax. That way I'll appreciate the real thing But the surface grinder would probably be a better start! (And thus, he heads further down the rabbit hole)

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Have you checked your stone to see if it is flat? clean your stone in a sink and use some glass cleaner and scotch brite or put some 200 grit sand paper on your clean surface plate, squirt the sand paper with glass cleaner and rub the stone on the sand paper. If you have another plate, that would be better. Then clean of your plate and carefully set the clean stone on your plate after wiping both with a bare hand to "feel" the dirt. Then check the pivot point on the stove by hinging it. The stone could be convex or high in the middle and rubbing it back and forth on the SE it gets low in the middle. You should buy a Norton MS-24 tapered slip stone - or a medium grit Indian grit stone. Some will grind a groove around the larger stone and break it in two. also is the plate siting on 3 points? You can use 1" x 1" inner tube rubber super glued on the bottom of the plate. Located at 30% from ends, 2 -30% from the side and the other end in the middle.

 

[Richard King 2]

Easton Maryland that looks like it is at tuckahoe machine shop . Do you think you will hold another class there at some I would definitely be interested in attending?!

Yes that was in the Tuckaho museum. One of the attendee's Paolo volunteers there and does do some scraping classes there. He was a A++ student and has rebuilt some machines there. The Museum is all sorts of thinks, Steam Engines and as the pictures, the machines are belt driven. He lives in Baltimore. He is the guy in the checkered shirt.

 

[Richard King 2]

Tuckahoe Steam and Gass Association Machine Shop Museum

Visit our Machine Shop Museum

tuckahoesteam.org

 

[DAM 79]

Yes that was in the Tuckaho museum. One of the attendee's Paolo volunteers there and does do some scraping classes there. He was a A++ student and has rebuilt some machines there. The Museum is all sorts of thinks, Steam Engines and as the pictures, the machines are belt driven. He lives in Baltimore. He is the guy in the checkered shirt.

Ok yes I have talked to him several times when I stop in there when they have the antique tractor pulls etc. I have also talked to Dan who also helps out there they have a awesome set up there with all the old machines and this fall I plan to stop out on the weekends when they hold there shop classes to meet some fellow hobby machinist

 

[rabler]

Have you checked your stone to see if it is flat? clean your stone in a sink and use some glass cleaner and scotch brite or put some 200 grit sand paper on your clean surface plate, squirt the sand paper with glass cleaner and rub the stone on the sand paper. If you have another plate, that would be better. Then clean of your plate and carefully set the clean stone on your plate after wiping both with a bare hand to "feel" the dirt. Then check the pivot point on the stove by hinging it. The stone could be convex or high in the middle and rubbing it back and forth on the SE it gets low in the middle. You should buy a Norton MS-24 tapered slip stone - or a medium grit Indian grit stone. Some will grind a groove around the larger stone and break it in two. also is the plate siting on 3 points? You can use 1" x 1" inner tube rubber super glued on the bottom of the plate. Located at 30% from ends, 2 -30% from the side and the other end in the middle.

I'll work on those steps. I've hit my limit for hand scraping for a couple days so its time to take a break, too sore.

I've been using the bare-hand dirt check on the plate, and checking the pivot points. I need to put that surface plate on some feet and clean the stone. I can see the stone is only polishing the outside edge of the straight edge casting, same area as the surface plate blues it, so I don't think the stone is causing a depression issue. Rather, I think it is like you pointed out w/ Keith Rucker, I didn't have the horizontal mill trammed right. The other face of the straight edge is much flatter. I did the two faces on different mills, quite some time appart. This experience will make sure I do it right the next time too.

Thanks for taking the time to make all of these suggestions!

 

[Richard King 2]

Some folks slide a coolant hose up the handle or wrap it with rubberized electrical tape or wear leather gloves. I have also had students drill and tap holes in the steel handle so they can put a vertical handle on the scraper handle. Use a round rubber bike steering handle.. Once you put a rubber sanding pad on the wood end and push with your body and not your hands and arms you will feel better. Learrning to scrape especially when the blade is dull or lapped wrong it makes hand scraping a real "pain".

 

[Janderso]

I was actually looking at purchasing the "Machine Tool Reconditioning" book on Ebay. Went back and looked and it was from you.

Small world.

As I recall, Richard has a colorful opinion of Mr. Connelly.