Trent Bosch hollowing scrapers feedback?

[Alan Heffernan]

I am planning to order a T. Bosch stabilizer/system and some tooling. I am considering including some of his hollowing teardrop scrapers in the order. At the moment I have 5/8" set (straight, bent, & extreme bend) and a straight 3/4" in my cart. I am leaning toward the negative rake grind.

From those of you that use them, feedback and insights on their performance would be appreciated.

 

[Richard Coers]

Personally, I'm the kind of guy that doesn't worry about having a perfectly smooth interior. I've found that not one general public person that sticks their finger inside to check my work. If someone does, they are a woodturner. I don't have any Bosch tools, but I do have a tear drop scraper. Since I went to my DIY camera system, I'm very confident using my 1/8" tool with a very light touch to knock down ridges. All the way down to 3/32" wall on some small hollow forms.

 

[Roger Wiegand]

I have and have used the TB scraper. Since pretty much the only audience for my work is the other guys at the turning club they are all going to stick their fingers in, so I try to be sure the sides are smooth at least as far as they can reach.

It works quite nicely, but I'm not aiming for a perfect interior finish so I haven't gotten in there with a boroscope to look for tearout.

 

[Alan Heffernan]

I have and have used the TB scraper. Since pretty much the only audience for my work is the other guys at the turning club they are all going to stick their fingers in, so I try to be sure the sides are smooth at least as far as they can reach.

It works quite nicely, but I'm not aiming for a perfect interior finish so I haven't gotten in there with a boroscope to look for tearout.

Thanks Roger, do you use the regular grind or negative rake? Do you use both straight and bent shaft tools?

BTW, my wife sticks her fingers in them and as my banker, she likes perfection as much as I do.

 

[hockenbery]

I do mostly face hollowing
I have the Bosch straight, bent, & extreme bent
I scrape the inside of my forms with a teardrop scraper on a Dennis Stewart bar
Basically the Same tool as Trent’s
Never tried a negative rake.

I don’t sand inside the forms a scraper makes them look smooth

 

[Dave Landers]

I have a number of Trent's hollowing tools. I have 2 of the bent teardrop scrapers (1/2 and 5/8, don't have a straight, haven't really needed it as the bent tool can get nearly to the bottom and taking light cuts the bend isn't a problem for me).

They do help with smoothing the surface - not just for when someone sticks their finger in, but to smooth over bumps and ridges left by the more pointy/regular tools. The teardrop shape just helps achieve a more even wall thickness.

The other thing is they are better at getting around the corner near the mouth of a form. I make some forms with a fairly flat top around the opening, and the regular bent tools won't do the job for me - the body of the tool bar gets in the way and the cutter can't engage the wood where I want it. But the teardrop can be rotated around till so that it'll access places the regular tool won't.

I have the regular (not negative rake) and find them just fine - haven't had any issue with them being too aggressive. Course, you could always buy extra teardrops or the other kind...

 

[Isaac Davis]

Off topic, but whenever I use my scraper inside a HF I always get so many snags, and it's just really difficult to get a good finish. I'm sure it's a me problem, but it sure is frustrating.

 

[Randy Heinemann]

If you're buying the stabilized from Trent, just be sure all the tools you're ordering are size compatible with the Stabilizer (although he might comment on that if you order something not compatible); 5/8" tools for the 5/8" Stabilizer. With the 3/4" Stabilizer you can use either size tool but with an adapter for the 5/8". I have the Stabilizer and Trent's hollowing tools, including the scraper. I don't have the NR scrapers since they weren't offered yet when I bought my tools. I have never had a catch with them so am not sure that it makes a difference. You could modify them yourself if the regular don't work for you. The Stabilizer is a great aid for hollowing and takes a lot of the abuse on shoulder and arms out of the process. It just makes hollowing more "fun".

 

[John Hicks]

With the regular scraper, you can tilt it and get a more controlled scrape. I have the negative rake also, but rarely use it.

 

[Norm Marentette]

Works great. I grind a negative rake and touch it up and take light cuts. Adjust the angle as Dave said. Produces a nice smooth finish and then light sanding to finish.

 

[hockenbery]

Off topic, but whenever I use my scraper inside a HF I always get so many snags, and it's just really difficult to get a good finish. I'm sure it's a me problem, but it sure is frustrating.

The scraper must be level or tilted down left to right but not tilted front to back. Used at center or higher you can’t get a catch.

When the scraper bevel contacts the wood you get a catch.

A common handheld catch occurs when tip the tool is down off level and the tool angle works pushing forward because there is no bevel contact.
Then you pull the tool backward either on the wood or to a point where you want to make another pass. Now the bevel makes contact on a curve or the upward pointing edge digs in.

If you use something like Jamieson or other trapped or articulated system be sure the bar is level. This will keep the the teardrop level front to back. Also lock to tool in so the scraper is level left to right.
Set the tool rest to be on cut on center. This avoids catches and bumps in the bottom center.

I routinely use the teardrop to cut the last 1/8” or a little more off the wall thickness.
The Bosch Visualizer makes this easy

 

[Roger Wiegand]

Mine has a regular grind, not a negative rake.

 

[Dave Landers]

A common handheld catch occurs when tip the tool is down off level and the tool angle works pushing forward because there is no bevel contact.

Another way to get something like a catch is if you have the tool rest too far forward. The straight portion of the bent tool needs to be on the tool rest - so that the cutter is in-line with the handle. Otherwise, with the bent portion of the tool on the rest, it'll want to torque around when the cutter touches the wood - the tool spins and might bang into something in there.

 

[Brian Gustin]

One technique I learned from using my Ellsworth hollowing tools, you start with the tool cutting edge pointing straight down and not touching wood, then rotate your wrist until your cutting tip starts making contact and then starts scraping - hard to get a catch that way except deeper in when you're getting near the bottom transition.... Don't know if it would work with those curved hollowers though , never tried those yet (don't have any)

 

[robo hippy]

Talking about how smooth you want the inside.... Flashback. I made a hollow form, and was sticking my fingers in to see how smooth the inside was. My daughter came up, she was 5 or so at the time, and said, "Gee dad, I can stick my whole hand inside...." I really need to try some more hollow forms.

robo hippy

 

[Randy Heinemann]

To me, the most important part of the inside of a hollow form is the surface nearest the opening. Since most people can't get their hands into the entire hollow form only the part that they can feel needs to be smooth. Smoothing the rest of the inside is really more for the turner him/herself.

Trent Bosch's scrapers do a great job of "roughly" smoothing the entire inside. To get the whole inside as smooth as the outside means finding some safe way to sand it all. Somehow, to me, it never seemed worth it.