Raised Panels

[Freetochat]

I am constructing kitchen cabinet doors in American White Oak, and have bought a set of panel raisers for the spindle moulder. The rails/styles are 20mm thick with a 5mm groove to hold the panel. I was going to raise the panels out of 15mm thick stock so that the back face of the panel is flush with the back face of the housing groove. Is this the correct method that is used? and Is the thickness of the panels too thin for this application?

Regards

John

 

[Scrit]

The rails/styles are 20mm thick with a 5mm groove to hold the panel. I was going to raise the panels out of 15mm thick stock so that the back face of the panel is flush with the back face of the housing groove. Is this the correct method that is used?

Yes

Is the thickness of the panels too thin for this application?

No. 15mm is thick enough for a flat-back panel. To avoid break-out machine the cross grain first and use a scrap block to further minimise break-out on the back edge. If you can reverse the block out through a sacrificial fence (or raise it up through the fence) whilst the machine is running (to create a sort of zero clearance fence) you should get a better quality of cut, too.

Scrit

 

[Freetochat]

Thanks Scrit, advice really appreciated.

 

[Scrit]

Is your cutter an overcut opr an under cut? (i.e. does it run above or below the workpiece)

Scrit

 

[Freetochat]

Here are pictures of the tooling. My understanding from sales were that they can be used over or under. On test cuts, I used the tool over the timber and held the panel on a sliding table using a hold down. I was looking for better accuracy in this setup as opposed to having the tooling under the timber.






Regards

John

 

[Scrit]

I was looking for better accuracy in this setup as opposed to having the tooling under the timber.

:-s The table of any woodworking machine is normally the reference surface and for profile work it is normal to use the visible face of the timber as the reference face, as in hand woodworking. That being the case you are referencing off the back face of the timber and might be storing up an accuracy problem for the future. The reasons are as folows:

- it is possible that the timbers were planed in more than one session and has slightly different thicknesses, or has even swelled between sessions on the spindle. Even 0.5mm difference can be very noticeable in an intricate cut. It can play havopc when jointing timber

- when running timber underneath a profile cutter there is a slight chance of any warp in the timber resulting in a deep cut in the middle (up-bowed)or ends (down-bowed) of the panel - much reduced by using the hold down, but nonetheless it's there. Conversely an undercut will potentially undercut in the centre (bowed upwards) or at the ends (down bowed), however this can be corrected by making a second, hand pass with something like a short Shaw guard in place rather than a hold-down cramp. You can always take material off, sticking it back on again, however......

- the further "out of the water" the cutter is raised the greater the amount of guarding you need around it. An undercut leaves the timber actually covering the block for much of the pass, so a broken tip will simply fall into the chamber below the table rather than possibly being ejected at arm height.

As you can probably tell I'm an undercutter. The problems I've mentioned don't occur very often, but they do occur. Choose a working method which avoids the problems to start with and you'll never have to cope with the issues.

May I take this opportunity to recommend Eric Stephensons' excellent book on the spindle moulder, "Spindle Moulder Handbook" [publ. Stobart-Davis, ISBN 0-85442-031-2 reprinted 1999)? Simply the best book ever published on the subject by an author who was at one time design engineer for Thos. Robinson & Sons of Rochdale, although the previous edition is now a bit out of date about tooling standards. Failing that there is some excellent free information about guarding and safety in publication 18 on the Spindle Moulder at the HSE website which might be worth looking at.

Regards

Scrit

 

[Freetochat]

Scrit - as usual you are a mine of good information. Thank you very much. When I make up a sample, I will take on board all your advice.

Regards

John