Making A New Tool: A Scraper

[Cliff]

I wanted to try one of those fancy pants carbide insert negative angle scrapers

 But the  bloody stinking things are like a hunnert dollahs and I didn't want to throw a C note at an unknown.

 

 

So I got me an  $11  carbide insert and a hunk of 5/8 bar stock

I threw the bar stock on my Makita chop saw with an abrasive blade, clamped it at a rakish angle with a big C clamp and cut the negative rake. No, I haven't a clue what angle I used  - - It just looked right.

 

Then it was onto my right angle hardened steel block I made when I was a toolmaker by trade and onto the drill press for  drilling and tapping.

LEMETELLYA I hate A36 Steel for tapping fine small threads but that's what the borg sells so it's what I used.

 

 

No I made not one single one of those drill point divits on my DP table.  That was the prior owner/drooling-morons.

But I did get the DP cheaply.

 

But I digress.

Not I gotta make a handle.

If I don't like the angle I can re cut it.

What a lovely excuse to turn a handle.

[Gene Howe]

Looks like a first class job, Cliff.

Let us know how it works out. 

[Ron Dudelston]

I'm with Gene....Keep us posted.  That has some real potential.

[lew]

Now that you have the angle already cut, I found this-

You can thank me later.

[Cliff]

HA HA HA HA   Well I didn't do any research on the angle.  I just Eyeballed it and  well we;ll see how it works out.

 

Truth be told the actual work took no longer than an hour.  The chop saw is fast fast fast. The drilling of a #29 through hole was fast and the tapping was the slowest taking maybe 5 minutes. 

I started it in the drill press just to get it true and finished by hand.

In A-36 steel, like 316 SST, when tapping small fine threads  ya gotta go in like maybe  a tenth of a turn and then back it out to break the chip. and that's the drill over and over again till you are through or at depth.

 

So if I don't like the angle or want to try another: All I gotta do is repeat the process.

[Cliff]

well I took lew's input seriously and  cut drilled and tapped the other end of the bar to 6-Degrees. Then mounted the cutter and gave it a whirl.

It scrapes really well and I can turn it on it's side and take a sharp slicing cut.   This is way far better than squandering a hunnert smackeroos on nothing more than a bar of steel with a cut end and a tapped hole.

[Cliff]

Here is is with it's handle

 

Works GREAT~!!!

 

 

[lew]

Sweet!

What did you use for the ferrule?

[Cliff]

The ferrule is 1.380" ID steel pipe wall thickness  a little more than 1/16".

 

I just looked at the image you linked to.

 It's kind of funny  titling it a HSS scraper with a carbide insert and then calls for 316 SST bar. Why Stainless ?  I can't guess but it's a beast to tap for small threads and brings nothing to the party by way of strength. .

[lew]

The ferrule is 1.380" ID steel pipe wall thickness  a little more than 1/16".

 

I just looked at the image you linked to.

 It's kind of funny  titling it a HSS scraper with a carbide insert and then calls for 316 SST bar. Why Stainless ?  I can't guess but it's a beast to tap for small threads and brings nothing to the party by way of strength. .

Not sure either why they used SS. If I remember, it was from a turning forum. Maybe it is just what the maker had on hand.

[John Morris]

The stainless bar won't rust with moisture from turning wet wood. But as long as you stay on top of the care of your tool and wipe it down after each use, it should be fine. Perhaps even keep a very light coat of oil on it. You'll want to disassemble the cutter from the bar after each use with wet wood to clean the threaded hole out at the bar, any moisture gets in there that cutter screw will rust solid in place.

[John Moody]

Very nice Cliff.

 

I made a couple of those a few years back. They are fun and easy and do a really nice job.

[Cliff]

Well 316 is what you use when  the  corrosion resistant Chrome in other grades of SST are insufficient to the task and you don't want the incredible  cost of Inconel.  316 is a very spendy metal with high chrome and nickel for corrosion resistance.

 

Maybe  the author simply had not a tiny clue what he was using but knew it was shiny and the only grade of SST he knew about was 316?  So - - - that's what he called it.   I've seen  lots and lots  of folks just default to the limited knowledge they have on hand and broad brush that  upon the whole world around them.

 

Any one with even a glancing knowledge of metals would be unlikely to first specify High Speed Steel and then later call it 316 SST and any one who knows metals would not bother to call for any grade of stainless at all where the  expensive alloy is not going to  bring anything to the party.

I used A36 which is the crud they sell at the borg.  They sell that because it is the cheapest steel in America,  even the whole world for that matter.  It's the alloy used in all forms of construction from bridges to buildings to  re-bar.   So it's plentiful and cheap.

But it's also strong, welds well, and rebounds nicely from being flexed and does not stress crack from bending (good Young's modulus).