# understanding "dropping on"



## steamingbill (Jan 13, 2013)

Hello,

I accept the advice given in another thread that "dropping on" is a dangerous practice and should be avoided and I will do so. The words "trapped cut" were mentioned.

Is it dangerous because when you push the timber down onto the spinning bit there is suddenly too many things (router bit, newly created shavings and original blank) trying to fit into a limited volume and something has to "give" and the results could be the blank splitting and timber fragments going everywhere ?

Am curious about the physics of it ..........

Tried searching dropping on but didnt find much - what other keywords should I use please ?

Regards

Bill


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## Dmeadows (Jun 28, 2011)

It's just my opinion, take it for what it's worth...

1. I don't really like the term "dropping on". Of course "dropping" anything on a spinning bit(or blade for that matter) is dangerous!

2. The method of pushing the work piece onto a spinning bit has been recommended by many sources that I trust. I personally have used the method many times. I always use a stop block both to control the start and stop points of the cut, and to prevent the work piece from kicking back. I also usually make the cut in several shallow passes.

3. Unless you are fortunate enough to have a power lift on your router table, I don't know of a better way to make some cuts.

4. Any operation can be dangerous if you are not paying close attention to what you are doing, don't plan carefully, or get distracted during the operation.

5. If _*you*_ don't feel comfortable with it, don,t do it. But personally I am quite comfortable with this particular operation. In many cases, doing the cut with a hand held plunge router may be more dangerous!

6: I know that there will be disagreement on this.

Just my opinion.

"Trapped cuts"(cutting with the work piece between the fence and the bit)on the other hand are a no-no.


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## OPG3 (Jan 9, 2011)

"Dropping on" is a quite vague terminology. As Duane has said, make deeper cuts in multiple passes. To me the term dropping sounds like you're turning loose - but with routing, it is anything but turning loose. If you need to make a non-continuous cut with a router, use start and stop blocks, which is easily done via clamped parts on a fence.
Stand on a bridge (over a river) and drop a football - it will float away at the speed of the current, the faster the currect - the sooner your football will disppear. Rivers don't move at router speeds, but unlike the football; you are not supposed to drop & watch - you must be prepared for the sudden applied torque on your workpiece. Attempting this properly on a piece of wood, requires experience of expectation; but none of us can hold-on to a piece that is being cut too deeply in one pass. My suggestion (and I completely agree with what Duane has told you) is to get some hands-on training. Without this, you may find yourself getting hands-off training which is very bad.
Being safe is SMART! Most men missing fingers have very good safety hints - make sure you are a learner versus a teacher. Start-off like you learned to ride a bicycle, slow and cautious. Otis Guillebeau from Auburn, Georgia


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## MikeMa (Jul 27, 2006)

Are you talking about doing a plunge cut on the router table? This often necessary when doing stopped dado's and grooves, and there is a right way to do it. Like any time when easing a work piece into a spinning bit, it is a pivot action, with part of the work piece against a solid surface. For doing a plunge cut, the edge furthest away from the start, should be to the right of the bit and on the router table and against the fence. For more of an edge to hold the piece in place while plunging a stop block clamped on your fence is good, and will also make sure you are in the right start position. This will take out all other variables you mentioned earlier. To actually make the plunge, bring the piece down like a draw bridge gradually on to the bit. The real risk if not done properly is the bit grabbing the piece and shooting it across your shop, potentially bringing your hand and fingers into the spinning bit. By using the table surface, fence and a stop block this will go a long way in doing this operation safely. As always, make sure you use feather boards and push blocks to keep your hands as far a way from the bit as possible. Also make sure your depth of cut is appropriate for the bit. If it is for a really small piece, look at either coming up with some jigs to hold it, or consider using hand tools.


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## denniswoody (Dec 11, 2011)

One technique I have used is to drill two holes in a line at the start point. The holes should be to the final desired depth.This gives the bit an opening that is not fully engaging the wood. From the start push forward as in a normal cut.


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## Mike (Nov 22, 2004)

Bill, This method can be safely used by someone who has experience with their router. It is not something to try when you first start out. Over time you develop a feel for how fast a bit is cutting and listening to your router will tell you to speed up or slow down. Dust collection is important because trapped chips and dust get recut which causes your wood to buck a little bit; you can hear and feel this happening. It requires awareness of keeping your wood tightly to the table and against the fence. Featherboards handle this in many situations but not for this type of cutting. And above all you must keep your hands and fingers well away from the bit.

We follow a rule for removing no more than 1/4' of material for the cleanest cuts and best results. When cutting through slots you must use a slower feed speed to allow the bit to do it's job and yet be fast enough to prevent burning. Building the plywood ski jigs requires through slots. In this situation I have the wood against the fence and slowly lower it onto the spinning bit until it cuts through. I then slowly feed the wood over the bit so it has time to cut and evacuate the chips. I keep my hands well away from the bit and change positions many times making sure to keep the wood down against the table and against the fence. When possible it is best to use start and stop blocks on your fence to limit board travel. Some pieces are so long that you must use reference marks on the fence. Note that the bit is set just high enough to come through the wood.

This is a method taught by The Router Workshop show and I highly recommend watching it.


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## bobj3 (Jan 17, 2006)

Hi Bill

" what other keywords should I use please ?"
Try what I should NOT do on a router table.

Most have a hand plunge router,it will do it the safe way ,you can clamp the lumber to the work bench or better yet make a ski jig..that's why I started using a ski jig..

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steamingbill said:


> Hello,
> 
> I accept the advice given in another thread that "dropping on" is a dangerous practice and should be avoided and I will do so. The words "trapped cut" were mentioned.
> 
> ...


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## Marco (Feb 21, 2009)

A question for all, when cutting key hole slots do you use the router table or a plunge router?

I recently made a bunch of plaques and when it came time for the key hole slots I used the router table. I did question the safety aspect but with start and stop blocks, pressing the wood firmly to the start block making the cut to the stop block and then back to the start block it seemed like a safe cut.


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## bobj3 (Jan 17, 2006)

Hi Jim

Not a safe way,you can buy or make a jig to do it the safe way,the error comes into place when you back the bit up to get it out of the hole, as I'm sure you know..the chips fill the slot up and can jam the bit or take the part for a little ride or make a real mess of the slot...

http://www.routerforums.com/jigs-fixtures/7276-hanging-slot-template.html

===



Marco said:


> A question for all, when cutting key hole slots do you use the router table or a plunge router?
> 
> I recently made a bunch of plaques and when it came time for the key hole slots I used the router table. I did question the safety aspect but with start and stop blocks, pressing the wood firmly to the start block making the cut to the stop block and then back to the start block it seemed like a safe cut.


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## steamingbill (Jan 13, 2013)

Thanks very much for replies.

Regards

Bill


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## bobj3 (Jan 17, 2006)

Hi Mike

I'm surprise you are not using a push pad on that type of job on the router table,looks like you are making a rail for your ski fixture..


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Mike said:


> Bill, This method can be safely used by someone who has experience with their router. It is not something to try when you first start out. Over time you develop a feel for how fast a bit is cutting and listening to your router will tell you to speed up or slow down. Dust collection is important because trapped chips and dust get recut which causes your wood to buck a little bit; you can hear and feel this happening. It requires awareness of keeping your wood tightly to the table and against the fence. Featherboards handle this in many situations but not for this type of cutting. And above all you must keep your hands and fingers well away from the bit.
> 
> We follow a rule for removing no more than 1/4' of material for the cleanest cuts and best results. When cutting through slots you must use a slower feed speed to allow the bit to do it's job and yet be fast enough to prevent burning. Building the plywood ski jigs requires through slots. In this situation I have the wood against the fence and slowly lower it onto the spinning bit until it cuts through. I then slowly feed the wood over the bit so it has time to cut and evacuate the chips. I keep my hands well away from the bit and change positions many times making sure to keep the wood down against the table and against the fence. When possible it is best to use start and stop blocks on your fence to limit board travel. Some pieces are so long that you must use reference marks on the fence. Note that the bit is set just high enough to come through the wood.
> 
> This is a method taught by The Router Workshop show and I highly recommend watching it.


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## Phil P (Jul 25, 2010)

steamingbill said:


> I accept the advice given in another thread that "dropping on" is a dangerous practice and should be avoided and I will do so.


Hi Bill

Despite the misgivings of another poster "dropping-on" is the correct wood machinists term to describe a situation where the mould(ing) starts part way along the timber and terminates short of the end, i.e. where the timber has to be "dropped-on" to the cutter make the cut. The term derives from spindle moulder (shaper) practice and is I can find its usage back to pre-WWII in texts (very few detailed wood machining texts were written prior to WWI). 

Dropping on is a _potentially hazardous_ process unless specific steps are taken to control the movement of the material, hence my earlier comments. The issue is that if done wrong the material, unconstrained, can be grabbed out of the operators hands by the cutter and turns into a projectile. In routing terms taking the router out of the table and making multiple passes with the router hand held with either the fence or cut depth adjustments used to control the amount of "bite" per pass is therefore preferable, but the approach taken with spindle moulders (shapers) can be applied to the router table

As nobody appears to have published full detail of the process I've made up some diagrams to show the way in which a trained wood machinist handles this on a spindle moulder (shaper). All views are meant to represent a conventional edge profile or grooving cutter and viewed vertically (from above)

*Fig.1* - A back stop (to the right) is firmly secured to the infeed end of the table. This has two functions; to control a kickback should one occur, and to act as a pivot point for the drop on. The back stop must be firmly fixed and of sufficient size, at least as tall as the material being worked - remember it needs to be able to withstand a kickback. It needs to extend well away from the fence so that the material can remain in full end-contact with it when starting the drop-on. There should be a gap between the back stop and the fence to prevent chips from becoming trapped between the material and the fence. Ideally some form of pressure pad, such as a Shaw guard, should be fitted above the cutter with a bevel-edged pad although a simple acrylic or polycarbonate cover should suffice in many cases because the material sizes used are not massive (shown on the drawing in purple)










Throughout this operation the material or jig needs to be held firmly _with both hands_ - this is one reason that trying to operate a power rise and fall unit at the same time is probably unsafe - you really do need both hands to control the cut adequately, placed on the material/jig *to the right of the cutter.* This position ensures that your hands will be thrown clear should a kickback occur - if you place one hand to the left of the cutter a kickback can result in that hand being drawn into the cutter. Pivot the material/jig into the fence on the leading corner keeping the trailing end in contact with the back stop. Continue until full contact with the fence is achieved. 

*Note: *If contact with the fence is made with the fence but there is a small gap between the trailing end of the material/jig and the back stop DO NOT ATTEMPT TO DRAW BACK THE WORK because you'll possibly get a kickback. Instead move the material out and drop on again










*Fig.2* - Once the material is in full contact with the fence it can be pushed forwards until it meets the front stop










*Fig.3* - At the end of the cut










*Fig.4* - Having completed the cut draw out the trailing end of the material/jig pivoting the leading corner of the material/jig against the fence

Done properly this cut is controllable. Without end stops and correct hand positioning this type of cut is known to be dangerous. 

The above notes and diagrams were taken from my original bench notes made some 40 odd years ago and just to be on the safe side before writing this and transcribing my original sketches I went and cross checked my notes with both the UK HSE (OHSA equivalent) web site and with the current City & Guilds (examining body) training text for wood machinists. My original notes proved to be spot-on which I think speaks volumes for the guy who taught me as training texts of that period were somewhat lacking in detail on this subject (and many others). He gave me sufficient training to ensure that I still have all ten fingers, although like many joiners I've got a few nicks and scratches here and there!

If you want chapter and verse on this, Bill, I can happily supply you with details of the relevant books to borrow from the library (I say borrow because only parts of the contents are all that relevant to routing)

As to blind routing (where you cannot see the cutter and it does not exit the sides of the material) there are a number of issues. The best known example of a manual machine which raises a cutter up into the work to cut recesses and profiles is the Onsrud Inverted Pin Router. In this machine the material to be routed is attached to the _underside_ of a template. The cutter is by default withdrawn below the table surface and the guide pin is withdrawn upwards (to enable "trapped cuts" to be made - a trapped cut in this case is one which does not exit the sides of the work, hence "trapped"). To make a cut an opening in the template is placed below the guide pin and whilst holding the jig in both hands the operation foot pedal is pressed. The guide pin is then lowered into the opening in the template and after a short delay (about 1 second) the cutter is plunged upwards into the work from beneath the table. The operator then moves the jig around until the recess is fully cleaned out. The foot pedal is operated again making the cutter withdraw below the table surface first and after that the guide pin withdraws allowing the jig to be moved to the next recess to be cut or removed from the table altogether. I'm trying to fins a video of this on the web - I have it on VHS somewhere, but I no longer have a player!

For the router table a similar system can be used - something like the MLCS Daisy Pin Router. In this system a recess should be made when making a trapped inner cut to allow space for the router cutter. This recess must be bigger and slightly deeper than the depth of cut of the router because if the cutter catches on the work at startup the operator will only have one hand available to hold the template/material (the other will be on the power switch). Similarly if anything were to go wrong when making the cut an emergency stop button which could be used with either the foot or knee would be, I'd think, essential. Making an up-plunge cut with a powered router lift is, in my opinion, another hazard because you need one hand on the switch to control the rise/fall leaving you only one hand to hold the workpiece. Hit a knot, thundershake, split or inclusion (anything from a piece of stone to a length or barbed wire or a bullet trapped, invisible, in the timber) and it's potentially going to get hairy - without the control pin and template it will get very hairy as there is nothing to prevent the material from being ejected. One point about trapped cuts such as this - dust extraction is absolutely essential if you are not to overheat and burn both the cutter and the workpiece - without it you get "churning" of the swarf which raises the temperature rapidltto scorch point. The safety differences between this DIY system and a commercial machine are obvious: commercial machinery always has easily accessible emergency stop buttons AND the all commercial pin routers (inverted or overhread) utilise foot controls for the rise and fall leaving BOTH hands free to control the workpiece. In terms of safety these are significant differences when making trapped internal cuts - for outside edge routing they are much less significant

It's possibly best to understand that when things go wrong on a router at 20,000 rpm or more human reaction time is just too slow to do anything at all before an injury occurs (I have the scars to prove that - 10HP Wadkin overhead pin router). It therefore makes sense to plan cuts properly and not to depend on "common sense" because it isn't that sensible

Hope that clarifies things

Phil

PS Sorry for the lateness of this reply, it would have gone on last night had my Broadband gone phut for a few hours (something to do with planned maintenance at the exchange.....) and I've had to work this morning


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## Phil P (Jul 25, 2010)

Marco said:


> A question for all, when cutting key hole slots do you use the router table or a plunge router?


Hi Marco

That sort of cut is performed much more safely with a plunge router, template and guide bush as others have intimated

Just because someone has a router table doesn't make it necessarily suitable for all cuts



bobj3 said:


> " what other keywords should I use please ?"
> Try what I should NOT do on a router table.
> 
> Most have a hand plunge router,it will do it the safe way ,you can clamp the lumber to the work bench


That must be a first, Bob, I'm in total agreement with you there :yes2:

Regards

Phil


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## OPG3 (Jan 9, 2011)

*Sorry guys:* It appears now that y'all are speaking of _horizontally_ dropping-on, my comments were referring to _vertically_ dropping-on. I often make both types of cuts, but have never personally thought of the horizontal aspect as "dropping-on".
Obviously, I need to learn more terminology.
Otis Guillebeau from Auburn, Georgia


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## DaninVan (Jan 1, 2012)

Otis; I think Phil's description would apply in either case...but he was illustrating the shaper technique. I don't believe you can 'vertically' drop-on to a shaper(?).
In any case, the thought of putting my 10 fingers that close to a router bit scares the bejesus out of me, especially when the expectation is that things_ are_ going to go pear shaped. Likely why I still HAVE 10 fingers.


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## Phil P (Jul 25, 2010)

OPG3 said:


> *Sorry guys:* It appears now that y'all are speaking of _horizontally_ dropping-on, my comments were referring to _vertically_ dropping-on. I often make both types of cuts, but have never personally thought of the horizontal aspect as "dropping-on".


I believe that either is classed as "dropping-on", but dropping on to a vertical bit set out from the fence is something that I've never seen permitted anywhere I've ever worked on grounds of safety so I'm hardly going to illustrate it, am I? If you needed to do that sort of cut I was always taught that you went off and used a pin router (back in the days when plungers were uncommon here). Obviously if your trade schools, wherever you are, are teaching that process as a safe procedure then their standards are somewhat different to ours where it has for a long time been regarded as a problematic cut to make safely on a router table. Either that or you folks can grow new fingers! :fie:

The need to make plunging cuts set-in from the edge SAFELY is exactly why recessors were invented, and from them overhead pin routers evolved in the 1920s. In due course the need of carpenters to do this sort of cut on site (mortises) resulted in Elu creating the world's first portable plunge router in 1949 and is why European carpenters and joiners are almost unanimous in choosing plunge routers over fixed base ones even when there is a choice available.

What I was trying to put across was the dynamics of the situation and the need to have back and front stops and ideally a side or top pressure as well. In the case of a vertical drop on cut you'd absolutely need to set-up a horizontal Shaw (SUVA) pressure guard like this:










_Above: Router table with horizontally acting Shaw (SUVA) type pressure guard to support thin workpieces. For vertical dropping-on this set-up would require end stops and the top edge of the hardwood fance plate would need to be chamfered-off._

to force the workpiece in against the router fence. In that case the stops would be set vertically, but you could only safely make a cut the same width as your cutter. It's the same principle. Just a different axis

Phil


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## Phil P (Jul 25, 2010)

DaninVan said:


> ...but he was illustrating the shaper technique. I don't believe you can 'vertically' drop-on to a shaper(?).


Hi Dan

Difficult. The inibility of the spindle moulder (shaper) to do such cuts was why the recessor was developed in the 1880s or 1890s:










_Above: Wadkin LQ Recessor - a sort of mult-speed drill press with side thrust bearings (to permit the use of profile cutters - woodworking "equivalent" to an engineers mill/drill machine) and a 3-axis table designed for patternmakers in the beginning. This machine was first produced in the late 1920s but was fundamentally similar to machines which had been made before the turn of the 20th Century in several countries apart from an electric motor replacing the overhead line shaft and flappy belt drive_

in that machine you can pretty much see the origins of the modern overhead industrial pin router (which developed from this with the availability of high speed bearings from the late 1920s onwards) with foot operated rise and fall allowing both hands to be used to control the jig or workpiece, facilities for drills as well as shaper-type cutters and even (in the case of the LQ) a special recess in the table to hold a guide pin for template routing. Note the same principle- leave the operator with both hands to hold/guide the work whilst the foot raises and lowers the cutter 

About the only time I've ever seen a traditional spindle moulder (shaper) used with a cutter on top was when using one of those aluminium stair housing jigs in conjunction with a guide arm or the box/dovetail joint cutter jigs sold from the early part of the 20th Century until the early 1970s (I'll dig up a couple of shots and post later if I can) - even there they are designed to feed in from the side

Regards

Phil


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## bobj3 (Jan 17, 2006)

Hey Phil 

Who makes that Mickey Mouse router table.. ?

==



Phil P said:


> I believe that either is classed as "dropping-on", but dropping on to a vertical bit set out from the fence is something that I've never seen permitted anywhere I've ever worked on grounds of safety so I'm hardly going to illustrate it, am I? If you needed to do that sort of cut I was always taught that you went off and used a pin router (back in the days when plungers were uncommon here). Obviously if your trade schools, wherever you are, are teaching that process as a safe procedure then their standards are somewhat different to ours where it has for a long time been regarded as a problematic cut to make safely on a router table. Either that or you folks can grow new fingers! :fie:
> 
> The need to make plunging cuts set-in from the edge SAFELY is exactly why recessors were invented, and from them overhead pin routers evolved in the 1920s. In due course the need of carpenters to do this sort of cut on site (mortises) resulted in Elu creating the world's first portable plunge router in 1949 and is why European carpenters and joiners are almost unanimous in choosing plunge routers over fixed base ones even when there is a choice available.
> 
> ...


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## Phil P (Jul 25, 2010)

Hi Bob

Well it's not Disney! It's an old Elu design still being sold by deWalt. I used it as an example because the Shaw (SUVA) guard supplied is probably one of the best available over here - much better than shop-bought plastic ones (and I also have the piccy on file). In any case didn't you realise that we don't have wide open spaces in the EU? and that our houses are, to quote the song, "little boxes, little boxes, and they're all made out of tickey tackey" (a bit like some older bits of California I've been to....)

Regards

Phil


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## Marco (Feb 21, 2009)

bobj3 said:


> Hi Jim
> 
> Not a safe way,you can buy or make a jig to do it the safe way,the error comes into place when you back the bit up to get it out of the hole, as I'm sure you know..the chips fill the slot up and can jam the bit or take the part for a little ride or make a real mess of the slot...
> 
> ...


Well I got lucky. I did check on the linked template and did find Daves site on Ebay. Got it in the works.


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## Mike (Nov 22, 2004)

BJ, I know you are asking tongue in cheek. This method is taught by Bob and Rick and is the easiest way to make this type of cut. As I mentioned I change my hand positions and am careful to keep well away from the router bit.


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