Increasing Z?

[amowry]

I'm curious if there are any ways to squeeze a bit more Z height out of this machine? I understand that the table is removeable, so I could replace it with an MDF table/spoilboard which would help me maximize the height. I've heard that with some of the other Shopbots the router or router mount can be moved upwards somewhat. I haven't seen the machine in person, so I'm not sure of the possibilities.

[steve_g]

Andrew...

Do you know which model we're talking about?

SG

[amowry]

I'm wondering about the Desktop specifically.

[steve_g]

Andrew...
Hopefully someone with better knowledge of the desktop will chime in here. I was able to squeeze a bit more Z from my PRT Alpha...

SG

[Max Girouard]

I just looked at mine, and you may be able to get another 1/8 inch if you slide it up a bit. I've started using stub length end mills to gain a little more Z and using jigs that bolt directly to the aluminum bed rather than having a spoil board.

[scottp55]

Max, just got Desktop, and primarily working on 1.75" hard maple. had considered removing t-slot entirely ala Brady's suggestion. Do you have any pictures of your jigs to stimulate these tired brain cells? Any help welcome. Pretty much setting up for production runs of a single item. Trying to make it easy and foolproof. A machinist who is helping our project has never worked on a machine this small, but he "thinks" in aluminum. scott

[bearcat]

How much Z are you looking for? Are you running a spindle or a router?

Ed

[scottp55]

Enough to surface and profile cut 8/4 walnut and maple with .5" safe Z. Scott

[scottp55]

oops, desktop with spindle- upper Z prox switch.

[bearcat]

To get greater tool clearance without removing the t-slot table, I re-mounted the spindle with the collet nut even with the bottom edge of the Z-axis back plate. This gave me enough clearance to machine a 3 layer laminate of MDF superlight 2.2" thick for a client's project. The block was registered and clamped to a 15mm (0.6") thick plywood jig mounted on the t-slot table. After surfacing to 2", the internal full depth holes were opened up with a 1/2" diameter 2.25" CEL 3 degree end mill. The safe Z was set to 0.125"

This change does limit the Z axis travel to the t-slot table surface but is no loss as I always use a 3/4" spoilboard on the DT.

Ed

[scottp55]

Ed, I just looked at it and it would gain me the entire thickness of the collet nut.Thanks scott

[Max Girouard]

Hi Scott,

Here is a photo of one of my jigs I use to carve mandola tops. The tops are not very thick but this is the same principle I use to carve the necks on our mandolins which are carved from stock that is two inches thick. I make the vacuum fixture out of phenolic and have a similar zero ring that I install in the phenolic. The phenolic is .25 thick, and the vacuum gasket channel is cut in about .187. I drilled a hole in the center of the vacuum grid lines and have the hose running out through one of the aluminum slots rather than out front as shown in the pictured jig. I recently cut some blocks that were 2.125 thick, using an extra long .25 end mill. My strategy there was not to use a vacuum jig but clamp it down directly to the aluminum t tracks with some clamps I purchased from another member here on the forum. The wood was actually 2.2, and cut the profiles to 2.125 thick leaving the blocks in the board. When done with the profile cuts I took it off the bot and flipped it upside down and passed it through the thickness sander to free up the blocks. They came out nice and clean. Eventually I plan on cutting necks that are about 3 inches thick. For that I'll slice the model and cut the first part with a stub end mill, then run the second part with a longer mill. Let me know if that helps, and I can get a better picture of my neck jig tomorrow.

[scottp55]

Thanks Max, like the zero-ring. thanks for the image and info, very helpful. You have pics of finished work? scott Never mind I'll check.

[rawhide]

hi max,your table design is great.what type of pump do you use?

[Max Girouard]

Thanks! I use one of these.............

http://www.veneersupplies.com/products/Vacuum-Pump---Rietschle-Thomas-315-CFM-120-VAC-Condition-Rebuilt.html

I didn't seal the mdf and I'm still pulling around -20 bar on mandola and mandolin sized plates made of spruce and maple.

[Hoytbasses]

Hi Max:

do you think that vacuum pump would have any problem with an acoustic archtop top/back plate?

thanks

Karl

[Max Girouard]

I think it would no problem. I would however seal the mdf or other substrate if it is porous. Mandolins are so small that I didn't need to, but for a full size archtop guitar I would.

[Hoytbasses]

I think it would no problem. I would however seal the mdf or other substrate if it is porous. Mandolins are so small that I didn't need to, but for a full size archtop guitar I would.

Thanks...... I'm not there yet... but inching closer......

kfh