Jr. Gent and Jr. Statesman Concerns

[Jim in Oakville]

<<<frank, the guys are correct about being able to get different sized holes from a given bit.....but for such things as pilot holes, clearance holes, dowel holes,ect. in wood it`s not really relevent.....doing a "test" on a woodshop grade drillpress(under 5k) and testing with a set of calipers you`re most likely not going to see a difference in hole diameter.......if you do wait an hour the check again, you`ll get a different reading......if like bruce you`re building rocket ships out of weird alloys then it`ll matter but for joe building cabinets or furniture no>>>

Good post Frank,

A few years ago I conducted a Design of Experiment (DOE) on hole drilling (aerospace application). The results indicated that the most important factors were Feed, Speed, Drill Sharpness and Coolant.

While this experiment was conducted on 7071 aluminum it's lessons were consistant with any material. We measured our critical quality features of hole drilling, surface finish quality of the drilled holes and hole diameters.

We found a strong interaction between Feed and Speed of the drilling process on hole diameter and surface finish. We also found in 7071 coolant was critical.

What I will take away from this DOE in wood is also just that, the interaction of feed and drill speed are important, so is the effect of heat on materials. Some materials respond differently to heat, and as you mentioned given time for some materials to cool after drilling you will get different diameters.

We also noted as a drill dulled that holes became larger and our heat sensors measured up to 30% greater hole temperatures.


So, Feed and Speed have an impact on hole quality as does Heat and Drill Shapness also has an impact on hole quality and heat generation. So what are the right Feeds and Speeds for Wood, what is the definition of Drill Sharpness? I don't know, but a repeatable and controlled process has a better chance of reproducing a hole of a quality that meets what you want, if you know how to control the input drilling factors.

Overkill perhaps for pen making[], but useful to know... given pen making a hole that is sufficent to allow a tube to be bonded is fine.


I have been using the CSUSA recommended drill for this size, I use epoxy for the bonding and I have made 25-30 of these pens (mostly stabilized wood and some acrylics)...I have not had a single failure...Just what I know, Just what I have experienced.[]

 

[DocStram]

I hate to sound "harsh" (as The Designer Guys would say on HGTV .... ask your wifey) but the reality is that we can't worry about whether or not CSUSA or any other retailer worries about what we think. Nor can we fret about whether they value our opinion, or our input or our thoughts. The hard cold reality of a capitalist society is that retailers worry about their profit margins.

Gotta go add my order to that Baron group buy. []

 

[PenWorks]

Not one to kick a dead horse around or kick a guy while he is down, but.....
A. The clip you get on the Havana is not the one pictured, and it is not for the better.
B. The woodworkers pencil is clearly a 1/2 shorter than the original version, it is now the same size as
the Sketcher pencil, no news or mention of this change, you find out when you recieve your order.
C. The same thing happened when they changed from the black thread coupler to the all platinum coupler.
There needs to be a disclaimer on the website site or a better attempt to have accurate photos or keep turners informed of these changes.
It doesn't take much, just another little heading to click on the left hand side bar that may say production changes.
I have always enjiyed the quality of products and service from CSU, but what has been coming down the pike lately leaves me pondering alternative sources.