What to do?

[Joe Porter]

I have some 2" cherry that I want to cut out some parts, etc. All the cuts are going to be profile cuts, I ordered a 2 1/8" .5 dia. UPshear end mill because I thought this would keep the kerf clear during the cut. I don't care about surface quality at this time. The bit company sent me a DOwnshear bit by mistake. They will exchange it, but they don't have the correct bit in stock and will take a week or so to make one.
My question is, will the downshear bit work OK? Should I take light cuts (I do anyway), and make my toolpaths where I can stop the file and clean out the kerf? I am not interested in speed, and this is a one time project. Should I just go ahead and do a regular toolpath with several light cuts and leave the kerf alone?
I have a Buddy Standard and I always have a good hold-down strategy. I would rather just keep the downshear bit and forge ahead and not hassle with the return. Any help in this matter would be greatly appreciated...joe

[adrianm]

I only every use down bits and, apart from when I was cutting recycled plastic, I've never had an issue with the chips staying in the kerf.

In fact I find it beneficial for some jobs as it means I can go for a thinner waste section between parts.

[Joe Porter]

Thanks for the reply, Adrian...joe

[scottp55]

Joe, Keep it!
It holds the part down better and eliminates a lot of chatter, And IF i can use it leaves a better edge quality.
Just saying with a "Teeny Machine"!
I prefer downcut for "Cutout" toolpaths as it has saved me a few times:)
Using ONsrud,WHiteside,.
On cherry , have a piece of scrap?
Never Dealt with cherry in those sized bits, BUT- (Deleted exceptions as they were weird) Shallow passes fast were much better than "normal" passes slow.

[Joe Porter]

OK, thanks, Scott. In my delusional un-experienced mind, I see these 2" worth of cherry shavings causing my stepper motors to lose steps and start a fire!. Oh well, I will be on hand with the kill switch and a fire extinguisher any way..joe

[gc3]

i use straight flute bits for cuts like this with a spiral ramp...cut a lot of hard tropical woods. set your feeds/speeds for proper chip load and there should be no problems

[bleeth]

No problem with a downcutter for this at all. I have always used either downcutters or compression bits for solid wood. For me, upcutters are for some plastic and aluminum only.

[Ajcoholic]

I have some 2" cherry that I want to cut out some parts, etc. All the cuts are going to be profile cuts, I ordered a 2 1/8" .5 dia. UPshear end mill because I thought this would keep the kerf clear during the cut. I don't care about surface quality at this time. The bit company sent me a DOwnshear bit by mistake. They will exchange it, but they don't have the correct bit in stock and will take a week or so to make one.
My question is, will the downshear bit work OK? Should I take light cuts (I do anyway), and make my toolpaths where I can stop the file and clean out the kerf? I am not interested in speed, and this is a one time project. Should I just go ahead and do a regular toolpath with several light cuts and leave the kerf alone?
I have a Buddy Standard and I always have a good hold-down strategy. I would rather just keep the downshear bit and forge ahead and not hassle with the return. Any help in this matter would be greatly appreciated...joe

Joe, I have cut a LOT of hard maple, birch, walnut, cherry and other hardwoods, with an 1/2" Onsrud two flute down spiral bit(s) - of a few different designs. Some smooth, some with the chip breaker design.

Both worked just fine - and yes, some of the chips do get sucked up the DC, some stay put in the groove. But there wasnt any issue in cutting.

I have pushed my Alpha buddy to take a full 1 1/2" (not recommended) cut to try. I now generally do multiple passes at about 1/2" deep to 3/4" per pass, IE, 3 or 4 passes to cut out an 1 3/4" part.

I do have some upcut spirals, but you know I seldom use them. I find the quality of cut with the down spiral bits (or a compression spiral) better overall.

[Joe Porter]

OK, thanks for all the replies, Guys. This makes me feel a lot better. I am starting a new project that requires 2" stock and have never cut that deep before. I have decided to try a Hal Taylor version of the Maloof style rocker. If it starts to work out, I will post some pictures. If not, .....joe

[ckurak]

Just a suggestion...

When I cut solid stock that thick I make multiple passes. And, in a particular order.

I have routed a curved profile on 1.5" hard maple successfully by routing about 1/2" at a time with a CLIMB CUT leaving an onion skin layer at the bottom. The skin is about 1.5 mm (0.06") thick.

Then, I do a single final pass that cuts through, and smooths the routed face, with a CONVENTIONAL CUT.

If you have small parts, consider using TABS to hold the part in place. After the final cut, I use a very sharp blade (scalpel works well) to cut the part loose from the scrap.

Be sure to NOT try to break the part loose by pulling the part UPWARDS from the scrap. There will be a good chance that the wood fibers will tear off the good piece and ruin your work. This is especially true of veneer plywood, but solid wood may sometimes do the same thing.

What I do, with my PRT and MDF spoilboard, is to screw the original wood to the table. Then, after routing, I remove the screws, hold the good piece down to the MDF table top, then lift the scrap upwards until the part breaks free. If the tabs are really thick and strong, you may need to use the sharp knife trick.

Finally, carefully sand the tab off by using a file or rasp. Be sure to sand in the direction of keeping the fibers intact. If you do this wrong once, you will probably remember what not to do again. :)

By the way, to answer your original question, I use one of three types of bits: compression (great for plywood), straight flute, and downward spiral (helps to hold the workpiece down to the table). I have never had a problem with chips in the way.

Of course, I never leave the building when the router is running, and I always am listening to the sound of the router. If something sounds different, I check it out immediately. With some experience, you will learn to "hear" the problems. I have heard a number of broken bits (actual pieces of metal embedded in the plywood core) over the years suddenly get quiet. That is even with the dust collector running.

Having a fire extinguisher available, and knowing where the STOP button is, is smart. On my machine the STOP button only stops the stepper motors, but not the router. So, I need to remember how/where to power off the router as well or the router may spin in place in the wood and will start a fire.

[Joe Porter]

Thanks for the helpful information, Charles. I have had my ShopBot for several years now, but never used it on hardwood this thick before, so yours and all others suggestions will be taken to heart. Not only am I breaking new ground on the depth of cut, I have a Buddy with a 24" wide table in the X direction and am going to be cutting some parts up to 44" long. So, will have to handle the stock more than usual. Thanks again for the replies..joe